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					            NOAA POLAR ORBITER DATA
                  USER'S GUIDE

   (TIROS-N, NOAA-6, NOAA-7, NOAA-8, NOAA-9
    NOAA-10, NOAA-11, NOAA-12, NOAA-13 AND
                   NOAA-14




                      May 2007 Revision


                           Edited by:

                         Jeffrey Robel


               U. S. Department of Commerce
      National Oceanic and Atmospheric Administration
National Environmental Satellite, Data, and Information Service
                National Climatic Data Center
          Remote Sensing and Applications Division

                   Veach-Baley Federal building
                         151 Patten Ave
                    Asheville, NC 28801-5001


                   Telephone: (828) 271-4836
                      Fax: (828) 271-4328
                 Email: ncdc.satorder@ noaa.gov




                                 i        NOAA POD Guide - Jan. 2002 Revisioni
NOAA POLAR ORBITER DATA USERS’S GUIDE                                                      i
Acknowledgments                                                                           vi
Disclaimer                                                                              viii
Acronyms and Abbreviations                                                                ix
List of Figures:                                                                          xi
List of Tables:                                                                          xii


1.0     Polar Orbiter System Description 1
  1.1      System Summary                                                               1-1
  1.2      Orbital Information                                                          1-6
  1.3      Procedure for Scheduling AVHRR LAC Data                                     1-12
  1.4      Miscellaneous Parameters for the Polar Orbiter Satellites                   1-14
     1.4.1      TIROS-N                                                                1-14
     1.4.2      NOAA-6                                                                 1-21
     1.4.3      NOAA-7                                                                 1-28
     1.4.4      NOAA-8                                                                 1-36
     1.4.5      NOAA-9                                                                 1-43
     1.4.6      NOAA-10                                                                1-50
     1.4.7      NOAA-11                                                                1-57
     1.4.8      NOAA-12                                                                1-66
     1.4.9      NOAA-13                                                                1-74
     1.4.10     NOAA-14                                                                1-82

2.0     Level 1b Data Base                                                              2-1
     2.0.1     Clock Information                                                        2-2
     2.0.2      IBM Conventions                                                         2-3
     2.0.3      Level 1b Data Set Names                                                 2-4
     2.0.4     Data Set Header                                                          2-6
  2.1      Level 1b Tape Formats                                                       2-10
     2.1.1     Record and File Structure                                               2-11
  2.2      Level 1b Data Record Formats                                                2-13
     2.2.1     Packed Data Format                                                      2-14
     2.2.2     16-bit Unpacked Data Format                                             2-14
  2.3      Data Volume per Tape                                                        2-15

3.0      AVHRR Level lb Data Base                                                       3-1
     3.0.1       AVHRR Instrument Description                                           3-1
  3.1       GAC Data                                                                    3-2
     3.1.1       Data Characteristics                                                   3-2
     3.1.2       Magnetic Tape Formats                                                  3-3
        3.1.2.1     Full Data Set Copies                                                3-3
        3.1.2.2     Selective Extract Subsets                                          3-10
           3.1.2.2.1     16-bit format                                                 3-10
           3.1.2.2.2 8-bit format                                                      3-11



                                            ii         NOAA POD Guide - Jan. 2002 Revisionii
  3.2       LAC/HRPT Data                                                             3-12
     3.2.1       Data Characteristics                                                 3-13
     3.2.2       Magnetic Tape Formats                                                3-13
     3.2.2.1     Full Data Set Copies                                                 3-13
        3.2.2.2     Selective Extract Subsets                                         3-15
           3.2.2.2.1 16-bit format                                                    3-15
           3.2.2.2.2 8-bit format                                                     3-16
  3.3       Calibration of AVHRR Data                                                 3-16
     3.3.1       Thermal Channel Calibration                                          3-17
        3.3.1.1     Non-Linearity Corrections (TIROS-N through NOAA-12)               3-19
        3.3.1.2     Non-Linearity Corrections (NOAA-13 and successors)                3-21
     3.3.2       Visible Channel Calibration                                          3-21

4.0      TOVS Level 1b Data                                                            4-1
  4.1      HIRS/2 Data                                                                 4-2
     4.1.1      Instrument Description and Data Characteristics                        4-2
     4.1.2      Magnetic Tape Formats                                                  4-3
        4.1.2.1   Full Data Set Copies                                                 4-3
        4.1.2.2   Selective Extract Subsets                                           4-10
  4.2      SSU Data                                                                   4-11
     4.2.1      Instrument Description and Data Characteristics                       4-11
     4.2.2      Magnetic Tape Formats                                                 4-12
        4.2.2.1   Full Data Set Copies                                                4-12
        4.2.2.2   Selective Extract Subsets                                           4-16
  4.3      MSU Data                                                                   4-17
     4.3.1      Instrument Description and Data Characteristics                       4-17
     4.3.2      Magnetic Tape Formats                                                 4-17
        4.3.2.1   Full Data Set Copies                                                4-18
        4.3.2.2   Selective Extract Subsets                                           4-23
  4.4      SBUV/2 Data                                                                4-23
     4.4.1      Instrument Description and Data Characteristics                       4-24
     4.4.2      Magnetic Tape Formats                                                 4-24
        4.4.2.1   Level 1b Data Set                                                   4-25
        4.4.2.2   Product Master File                                                 4-25
        4.4.2.3   Historical Instrument File                                          4-25
  4.5      Calibration of TOVS Data                                                   4-25
     4.5.1      Thermal Channel Calibration                                           4-26
     4.5.2      Visible Channel Calibration                                           4-27

5.0      NESDIS Operational Products                                               5-1
  5.1      TOVS Sounding Product                                                   5-8
     5.1.1      TOVS Sounding Product (Jan. 1979 - March 8, 1992)                  5-8
        5.1.1.1   TOVS Quality Information File (Sept. 1989 - March 8, 1992      5-15
     5.1.2      TOVS Sounding Product (March 9, 1992 - May 31, 1998)             5-18
        5.1.2.1   TOVS Sounding Quality Information File (March 9, 1992 - Present)
                                                                                 5-24



                                          iii        NOAA POD Guide - Jan. 2002 Revisioniii
     5.1.3       RTOVS Sounding Product (October 22, 1997 - present)                5-26
  5.2       Sea Surface Temperature (SST) Products                                  5-27
     5.2.1       SST Field Format                                                   5-28
        5.2.1.1     Directory Record Format                                         5-32
        5.2.1.2     Field Documentation Record                                      5-33
        5.2.1.3     Field Data Record Format                                        5-37
     5.2.2       SST Observation File                                               5-39
        5.2.2.1     Seven Day SST Observation File                                  5-40
        5.2.2.2     Eight Day SST Observation                                       5-47
     5.2.3       SST Monthly Mean Archive                                           5-50
  5.3       Mapped GAC Products                                                     5-52
     5.3.1       Mapped GAC (Polar Stereographic) Product (1979 - Oct. 26, 1994) 5-52
     5.3.1.1     Mapped GAC (Polar Stereographic) Product - Oct. 26, 1994 to present
                                                                                    5-55
     5.3.2       Mapped GAC (Mercator)                                              5-61
        5.3.2.1     Mapped GAC (Mercator) Product - Oct. 26, 1994 to present        5-62
  5.4       Radiation Budget Products                                               5-63
     5.4.1       Monthly Radiation Budget                                           5-64
        5.4.1.1     Old Monthly Radiation Budget format                             5-64
        5.4.1.2     New Monthly Radiation Budget Format                             5-67
     5.4.2       Seasonal Radiation Budget Product                                  5-72
        5.4.2.1     10-Year Mercator Radiation Budget Product                       5-74
     5.4.3       Monthly Mean Radiation Budget Products                             5-75
        5.4.3.1     Monthly Mean Radiation Budget Products (Oct. 1, 1987 to present)
                                                                                    5-75
        5.4.3.2     Monthly Mean Radiation Budget Products (before Oct. 1,1987      5-77
           5.4.3.2.1 Monthly Mean Radiation Budget (2.5 x 2.5 degree Mercator Arrays
           before Oct. 1, 1987)                                                     5-77
           5.4.3.2.2 Monthly Mean Radiation Budget (Polar Stereographic Arrays
           before Oct. 1, 1987)                                                     5-78
  5.5       SBUV/2 Ozone Products                                                   5-79

Appendix A:      Polar Stereographic Earth Location                                  A-1

Appendix B:      Unpacking LAC/HRPT Data                                              B-1

Appendix C:      Field Station HRPT Data Format                                       C-1

Appendix D:    Polar Orbiter Archived TOVS Sounding Data Change and
Problem Record                                                                       D-1

Appendix E:    Historical Record of Significant Events Affecting the SST,
Radiation Budget, and Aerosol Products Produced from TIROS-N series AVHRR
Data                                                                       E-1
  E.1    CHANGES MADE TO NOAA PRODUCTS                                     E-1
  E.2    CHANGES MADE TO NAVY SST OBSERVATION PRODUCT                     E-44



                                         iv          NOAA POD Guide - Jan. 2002 Revisioniv
APPENDIX F:    Using Brouwer-mean elements from TBUS Part IV                    F-1

APPENDIX G:     The NOAA Satellite Information System (NOAASIS) Internet
Web Site                                                               G-1

Appendix H:   Conversion Algorithm for Orbital Parameters                      H-1

Appendix J:   Selected References                                               J-1

Appendix K:   Original Level 1b formats Valid to Sept. 8, 1992                 K-1

Appendix L:   Level 1b Formats Valid from Sept. 8, 1992 to Nov. 15, 1994        L-1

Appendix M:   New HIRS Calibration Procedure (NOAA-12 Only)                    M-1




                                      v         NOAA POD Guide - Jan. 2002 Revisionv
Acknowledgments

This document is the cumulative effort of many people in NOAA/NESDIS, both directly
and indirectly, to whom I am most grateful. I wish to express my appreciation to Greg
Hunolt (now of NASA/GSFC) for his direction and guidance on this document since its
inception in 1978. Users of this document have been very supportive in informing me of
errors that they have encountered in using it, for which I am very grateful. I believe that
user feedback has played a large part in keeping the errors in this document to a
minimum.

I sincerely thank Emily Harrod, Ellen Brown, John Sapper, Tom Wrublewski, Joe
Askew, Stan Brown, Charles Walton, Nagaraja Rao and Tom Snell (all of
NOAA/NESDIS) for the technical expertise and guidance in their respective areas. Also,
thanks goes to Geof Goodrum for his patience and expertise in WORDPERFECT and
supporting software, Garry Ayres for his help in understanding the SSB Level 1b
retrieval software and Jeff Robel for his help with the information regarding the Data
Services Branch (all of SSB).

My apologies to those people that I may have overlooked.

Katherine B. Kidwell

P.S. In October 1995, this document was converted into HTML and placed on the World
Wide Web. This was an enormous task which took several weeks of concerted effort. The
tables, figures and equations required special attention because they could not be directly
converted into HTML. They were made into GIF images and linked to the document. I
wish to express my sincere appreciation to Jeannette Rivera, Jeff Robel and Larry Arnold
(NODC) for all their hard work on this project.

P.P.S. In January 1997, this document was revised (for the last time for the TIROS-N
through NOAA-14 series) plus all the tables and figures were retyped and redrawn,
respectively. This was done for two reasons: to improve the appearance of the document
on the World Wide Web and to create a version which was suitable for capturing on a
CD-ROM. Special thanks go to Deanna Lallemont who carefully retyped most of the
160+ tables and to Jeannette Rivera for converting the entire document into HTML and
dealing with the many and varied idiosyncrasies of WordPerfect and HTML. I could not
have done this document without their help. Also, thanks go to Doug Ross and Axel
Graumann for their assistance on the section regarding the ordering of data products.

P.P.P.S. In June 2001, this document was made <a
href="http://www.section508.gov/">"Section 508"</a> compliant so that this website
was accessible to people with disabilities. This was a monumental task and I wish to offer
my sincere appreciation to Jeannette Rivera (NCDC/CSD/SSB) for all her hard work
inresearching this federal regulation and figuring out it's implications to the Polar Orbiter
Data User's Guide website. She diligently went through thousands of lines of html and




                                            vi          NOAA POD Guide - Jan. 2002 Revisionvi
then ran the html code through three different software packages to get the final "Bobby"
approval. This task could not have been completed without her help and guidance.




                                         vii         NOAA POD Guide - Jan. 2002 Revisionvii
Disclaimer

While every effort has been made to ensure that this documentation is accurate and
reliable, NOAA cannot assume liability for any damages caused by inaccuracies in the
NOAA polar orbiter data or documentation, or as a result of the failure of the data or
software to function in a particular manner. The software (included in the appendices)
was developed by the U.S. Government and is not intended for resale. The user should be
aware that phone numbers, fax numbers, addresses and Internet Uniform Resource
Locators (URLs) are subject to change and cannot be expected to remain constant.
NOAA makes no warranty, expressed or implied, nor does the fact of distribution
constitute a warranty.

The NOAA Polar Orbiter Data User’s Guide provides a significant source of information
for the TIROS-N through the NOAA-14 satellites. As the data processing and storage
technology has progressed over time, the machines used to process the data and the
methods of archiving and retrieving satellite data and products have changed
dramatically. The document has not been changed to reflect those changes

Questions concerning the retrieval of satellite data and products can still be directed to
the National Climatic Data Center by telephone, mail, email or the NCDC home page.
The mailing address for NCDC is:

       National Climatic Data Center
       NOAA/NESDIS
       Veach-Baily Federal Building
       151 Patton Ave, rm 120
       Asheville, NC 28801-5141

The telephone number is (828)271-4800.

The email address is ncdc.satorder@noaa.gov

The URL for the NCDC home page is www.ncdc.noaa.gov.

These documents are best viewed in Netscape 6.0, Mozilla, or Internet Explorer 5.0 or
higher.




                                          viii         NOAA POD Guide - Jan. 2002 Revisionviii
           Acronyms and Abbreviations

 ASCII    American Standard Coded Information Interface
  ATN     Advanced TIROS-N
AVHRR     Advanced Very High Resolution Radiometer
    BB    Blackbody
  BCD     Binary Coded Decimal
   BPI    Bytes per Inch
   BPS    Bits per Second
C & GCP   Climate and Global Change Program (NOAA)
   CCR    Cloud Cover Radiometer
   CCT    Computer Compatible Tape
  CDA     Command and Data Acquisition
  CDB     Coefficient Data Base
CEMSCS    Central EnvironMental Satellite Computer System
 CNES     Centre National d’Etudes Spatiales
 COST     Customer Order Servicing and Tracking
 DACS     Data Acquisition and Control Subsystem
 DCDB     Data Collection and Direct Broadcast Branch
   EBB    Electronic Bulletin Board
EBCDIC    Extended Binary Coded Decimal Interchange Code
   ECS    Electronic Catalog System
   EOF    End of File
 ERBE     Earth Radiation Budget Experiment
 FGGE     First GARP Global Experiment
   FOV    Field of View
  GAC     Global Area Coverage
 GARP     Global Atmospheric Research Program
 GELDS    Grid and Earth Location Data System
  GMT     Greenwich Mean Time (Zulu)
   HIF    Historical Instrument File
 HIRS/2   High Resolution Infrared Radiation Sounder/2
 HRPT     High Resolution Picture Transmission
  IFOV    Instantaneous Field of View
 ILABS    Image Library Browse System
   IPB    Interactive Processing Branch
    IR    Infrared
   LAC    Local Area Coverage
   LSB    Least Significant Bit
   LST    Local Solar Time
  MSB     Most Significant Bit
  MSU     Microwave Sounding Unit
   N/A    Not Available
 NCDC     National Climatic Data Center (NOAA)


                        ix        NOAA POD Guide - Jan. 2002 Revisionix
  NEdT      Noise Equivalent Differential Temperature
  NEdN      Noise Equivalent Differential Radiance
 NESDIS     National Environmental Satellite, Data and Information
            Service
   NMC      National Meteorological Center
  NOAA      National Oceanic and Atmospheric Administration
 NOAA SIS   NOAA’s Electronic Bulletin Board for Satellites
  NORAD     North American Air Defense Command
  OSCAR     Online Satellite Access and Request System
OSDPD/PSB   Office of Satellite Data Processing and Distribution/Product
            Systems Branch
  PMF       Product Master File
 POES       Polar-orbiting Operational Environmental Satellites (NOAA)
  PRT       Platinum Resistance Thermometer
  P/N       Pheudo Noise
   QC       Quality Control
ORA/ASB     Office of Research and Applications/Atmospheric Sciences
            Branch
   SAA      Satellite Active Archive
 SADDS      Satellite Archive Data Delivery System
  SAIDS     Satellite Archive Image Delivery System
   SAR      Search and Rescue
  SBBC      Solar Blackbody Contamination
 SBUV/2     Solar Backscatter Ulraviolet Radiometer/2
   SSB      Satellite Services Branch
   SEM      Space Environment Monitor
  SOCC      Satellite Operations Control Center
    SR      Scanning Radiometer
   SST      Sea Surface Temperature
   SSU      Stratospheric Sounding Unit
   TBM      Terabit Memory
    TIP     TIROS Information Processor
  TIROS     Television InfraRed Observation Satellite
  TOGA      Tropical Ocean and Global Atmospheric Project
   UEF      User Ephemeris File
   URL      Uniform Resource Locator
  USSC      U.S. Space Command (formally NORAD)
   UTC      Universal Time Code
    UV      Ultra Violet
   VIS      Visible
  WWW       World Wide Web




                            x          NOAA POD Guide - Jan. 2002 Revisionx
List of Figures:

Figure 1.1-1. Satellite Track Template- S. H.                                   1-4
Figure 1.1-2. Satellite Track Template – N.H.                                   1-5
Figure 1.1-3. Solar Zenith Angle                                                1-6
Figure 1.2-1 AVHRR Orbital SwathTemplate                                        1-9
Figure 1.2-2. AVHRR Orbital Swath Template                                     1-10
Figure 1.4.1-1. Spectral Response Curve TIROS-N AVHRR Channel 1.               1-17
Figure 1.4.1-2. Spectral Response Curve TIROS-N AVHRR Channel 2.               1-18
Figure 1.4.1-3. Spectral Response Curve TIROS-N AVHRR Channel 3.                 19
Figure 1.4.1-4. Spectral Response Curve TIROS-N AVHRR Channel 4.               1-20
Figure 1.4.2-1. Spectral Response Curve NOAA-6 AVHRR Channel 1.                1-24
Figure 1.4.2-2. Spectral Response Curve NOAA-6 AVHRR Channel 2.                1-26
Figure 1.4.2-3. Spectral Response Curve NOAA-6 AVHRR Channel 3.                1-26
Figure 1.4.2-4. Spectral Response Curve NOAA-6 AVHRR Channel 4.                1-27
Figure 1.4.3-1. Spectral Response Curve NOAA-7 AVHRR Channel 1.                1-31
Figure 1.4.3-2. Spectral Response Curve NOAA-7 AVHRR Channel 2.                1-32
Figure 1.4.3-3. Spectral Response Curve NOAA-7 AVHRR Channel 3.                1-33
Figure 1.4.3-4. Spectral Response Curve NOAA-7 AVHRR Channel 4                 1-34
Figure 1.4.3-5. Spectral Response Curve NOAA-7 AVHRR Channel 5.                1-35
Figure 1.4.4-1. Spectral Response Curve NOAA-8 AVHRR Channel-1                 1-39
Figure 1.4.4-2. Spectral Response Curve NOAA-8 AVHRR Channel-2                 1-40
Figure 1.4.4-3. Spectral Response Curve NOAA-8 AVHRR Channel-3                 1-41
Figure 1.4.4-4. Spectral Response Curve NOAA-8 AVHRR Channel-4.                1-42
Figure 1.4.5-1. Spectral Response Curve NOAA-9 AVHRR Channel-1                 1-46
Figure 1.4.5-2. Spectral Response Curve NOAA-9 AVHRR Channel-2.                1-47
Figure 1.4.5-3. Spectral Response Curve NOAA-9 AVHRR Channel-3.                1-48
Figure 1.4.5-4. Spectral Response Curve NOAA-9 AVHRR Channel-4                 1-49
Figure 1.4.6-1. Spectral Response Curve NOAA-10 AVHRR Channel-1.               1-53
Figure 1.4.6-2. Spectral Response Curve NOAA-10 AVHRR Channel-2.               1-54
Figure 1.4.6-3. Spectral Response Curve NOAA-10 AVHRR Channel-3                1-55
Figure 1.4.6-4. Spectral Response Curve NOAA-10 AVHRR Channel-4.               1-56
Figure 1.4.7-1. Spectral Response Curve NOAA-11 AVHRR Channel-1                1-61
Figure 1.4.7-2. Spectral Response Curve NOAA-11 AVHRR Channel-2                1-62
Figure 1.4.7-3. Spectral Response Curve NOAA-11 AVHRR Channel-3.               1-63
Figure 1.4.7-4. Spectral Response Curve NOAA-11 AVHRR Channel-4.               1-64
Figure 1.4.7-5. Spectral Response Curve NOAA-11 AVHRR Channel-5                1-65
Figure 1.4.8-1. Spectral Response Curve NOAA-12 AVHRR Channel-1                1-69
Figure 1.4.8-2. Spectral Response Curve NOAA-12 AVHRR Channel-2                1-70
Figure 1.4.8-3. Spectral Response Curve NOAA-12 AVHRR Channel-3.               1-71
Figure 1.4.8-4. Spectral Response Curve NOAA-12 AVHRR Channel-4                1-72
Figure 1.4.8-5. Spectral Response Curve NOAA-12 AVHRR Channel-5                1-73
Figure 1.4.9-1. Spectral Response Curve NOAA-13 AVHRR Channel-1                1-77
Figure 1.4.9-2. Spectral Response Curve NOAA-13 AVHRR Channel-2                1-78
Figure 1.4.9-3. Spectral Response Curve NOAA-13 AVHRR Channel-3                1-79
Figure 1.4.9-4. Spectral Response Curve NOAA-13 AVHRR Channel-4                1-80



                                     xi        NOAA POD Guide - Jan. 2002 Revisionxi
Figure 1.4.9-5. Spectral Response Curve NOAA-13 AVHRR Channel-5                     1-81
Figure 1.4.10-1. Spectral Response Curve NOAA-14 AVHRR Channel-1                    1-85
Figure 1.4.10-2. Spectral Response Curve NOAA-14 AVHRR Channel-2                    1-86
Figure 1.4.10-3. Spectral Response Curve NOAA-14 AVHRR Channel-3                    1-87
Figure 1.4.10-4. Spectral Response Curve NOAA-14 AVHRR Channel-4                    1-88
Figure 1.4.10-5. Spectral Response Curve NOAA-14 AVHRR Channel-5                    1-89
Figure 2.0.1-1. Typical Time Drift Δt                                                2-3
Figure 2.0.4-1. Format of the Time Code for both Start and Stop Times                2-9
Figure 2.2.1-1 Packed Data Format for AVHRR Data                                    2-14
Figure 2.2.2-1 Unpacked Data Format for AVHRR Data                                  2-15
Figure 5.1.1-1. Structure of TOVS Sounding Product Tape                             5-10
Figure 5.2.2.1-1 Structure of the Seven Day SST Observation File                    5-41
Figure 5.3.1-1. Arrangement of IR Day and VIS Data on Polar Stereographic Map.      5-53
Figure 5.3.2-1. Arrangement of Data on Mercator Map.                                5-62
Figure A-1. Earth’s Cross-section to Derive Latitude                                 A-2
Figure A-2. Deriving the Longitude from Polar Stereographic Map                      A-3
Figure A-3. Layout of Mapped Polar Stereographic Hemispheres                         A-5
Figure A-4. Layout of Mapped Polar Stereographic Northern Hemisphere                 A-7

List of Tables:

Table 1.2-1. Ascending and descending node times in LST.                           1-7
Table 1.2-2. Launch and data available dates for the TIROS-N series satellites.    1-7
Table 1.2-3. Brouwer mean orbital elements for TIROS-N on Oct. 24, 1978 at 0000 UT
                                                                                  1-11
Table 1.2-4. Orbital reference information (Ephemeris data) for TIROS-N Orbit 262.
                                                                                  1-11
Table 1.4.1-1. TIROS-N Central Wave Numbers for AVHRR IR Channels.                1-14
Table 1.4.1-2. TIROS-N TOVS Channel Spectral Response and HIRS/2 Thermal Band-
Correction Coefficients.                                                          1-15
Table 1.4.1-3. Corrected values for TIROS-N Nsp.                                  1-15
Table 1.4.1-4. Non-linearity errors for TIROS-N Channel 4.                        1-16
Table 1.4.1-5. PRT Coefficients for all Instruments on TIROS-N (from NESS 107) 1-16
Table 1.4.2-1. NOAA-6 Central Wave Numbers for AVHRR IR Channels.                 1-21
Table 1.4.2-3. Non-linearity errors for NOAA-6 Channel 4.                         1-22
Table 1.4.2-4. Corrected values for NOAA-6 Nsp.                                   1-23
Table 1.4.2-5. PRT Coefficients for all Instruments on NOAA-6 (from NESS 107) 1-23
Table 1.4.3-1. NOAA-7 Central Wave Numbers for AVHRR IR Channels.                 1-28
Table 1.4.3-2. NOAA-7 TOVS Channel Spectral Response and HIRS/2 Thermal Band-
Correction Coefficients.                                                          1-28
Table 1.4.3-3. Non-linearity errors for NOAA-7 Channels 4 and 5.                  1-29
Table 1.4.3-4. Corrected values for NOAA-7 Nsp.                                   1-29
Table 1.4.3-5. PRT Coefficients for all Instruments on NOAA-7 (from NESS 107) 1-30
Table 1.4.4-1. NOAA-8 Central Wave Numbers for AVHRR IR Channels.                 1-36
Table 1.4.4-2. NOAA-8 TOVS Channel Spectral Response and HIRS/2 Thermal Band-
Correction Coefficients.                                                          1-36



                                        xii        NOAA POD Guide - Jan. 2002 Revisionxii
Table 1.4.4-3. Non-linearity errors for NOAA-8 Channel 4.                       1-37
Table 1.4.4-4. Corrected values for NOAA-8 Nsp.                                 1-37
Table 1.4.4-5. PRT Coefficients for all Instruments on NOAA-8 (from NESS 107) 1-37
Table 1.4.5-1. NOAA-9 Central Wave Numbers for AVHRR IR Channels.               1-43
Table 1.4.5-2. NOAA-9 TOVS Channel Spectral Response and HIRS/2 Thermal Band-
Correction Coefficients.                                                        1-43
Table 1.4.5-3. Non-linearity errors for NOAA-9 Channels 4 and 5.                1-44
Table 1.4.5-4. Corrected values for NOAA-9 Nsp.                                 1-44
Table 1.4.5-5. PRT Coefficients for all Instruments on NOAA-9 (from NESS 107) 1-44
Table 1.4.6-1. NOAA-10 Central Wave Numbers for AVHRR IR Channels.              1-50
Table 1.4.6-2. NOAA-10 TOVS Channel Spectral Response and HIRS/2 Thermal Band-
Correction Coefficients.                                                        1-50
Table 1.4.6-3. Non-linearity errors for NOAA-10 Channel 4.                      1-51
Table 1.4.6-4. Corrected values for NOAA-10 Nsp.                                1-51
Table 1.4.6-5. PRT Coefficients for all Instruments on NOAA-10 (from NESS 107) 1-52
Table 1.4.7-1. NOAA-11 Central Wave Numbers for AVHRR IR Channels.              1-57
Table 1.4.7-2. NOAA-11 TOVS Channel Spectral Response and HIRS/2 Thermal Band-
Correction Coefficients.                                                        1-57
Table 1.4.7-3. Non-linearity errors for NOAA-11 Channel 4.                      1-58
Table 1.4.7-4. Non-linearity errors for NOAA-11 Channel 5.                      1-59
Table 1.4.7-5. PRT Coefficients for all Instruments on NOAA-11 (from NESS 107) 1-59
Table 1.4.8-1. NOAA-12 Central Wave Numbers for AVHRR IR Channels.              1-66
Table 1.4.8-2. NOAA-12 TOVS Channel Spectral Response and HIRS/2 Thermal Band-
Correction Coefficients.                                                        1-66
Table 1.4.8-3. Non-linearity errors for NOAA-12 Channel 4.                      1-67
Table 1.4.8-4. Non-linearity errors for NOAA-12 Channel 5.                      1-67
Table 1.4.8-5. PRT Coefficients for all Instruments on NOAA-12 (from NESS 107) 1-68
Table 1.4.9-1. NOAA-13 Central Wave Numbers for AVHRR IR Channels.              1-74
Table 1.4.9-2. NOAA-13 TOVS Channel Spectral Response and HIRS/2 Thermal Band-
Correction Coefficients.                                                        1-74
Table 1.4.9-3. Non-linearity errors for NOAA-13 AVHRR Channels 4 and 5.         1-75
Table 1.4.9-4. Non-linearity coefficients and radiance of space for NOAA-13 AVHRR
Channels 4 and 5 (Alternate method).                                            1-76
Table 1.4.9-5. PRT Coefficients for all Instruments on NOAA-13 (from NESS 107) 1-76
Table 1.4.10-1. NOAA-14 Central Wave Numbers for AVHRR IR Channels.             1-82
Table 1.4.10-2. NOAA-14 TOVS Channel Spectral Response and HIRS/2 Thermal
Band-Correction Coefficients.                                                   1-82
Table 1.4.10-3. Radiance correction coefficients for NOAA-14 AVHRR              1-84
Table 1.4.10-5. PRT Coefficients for all Instruments on NOAA-14 (from NESS 107) 1-84
Table 2.0.3-1. Data set name qualifiers.                                         2-5
Table 2.0.4-1. Data set Header Record Format for TOVS (after September 8, 1992). 2-6
Table 2.0.4-2. Data Set Header record format for AVHRR (after Nov. 15, 1994).    2-7
Table 2.0.4-3. Spacecraft ID.                                                    2-8
Table 2.0.4-4. Data Type Codes.                                                  2-8
Table 2.0.4-5. DACS Status Information Format.                                  2-10
Table 2.1.1-1. TBM Header Record Format.                                        2-12



                                     xiii        NOAA POD Guide - Jan. 2002 Revisionxiii
Table 2.1.1-2. Character Code Conversion (ASCII).                                    2-13
Table 2.3-1. Level 1b Data Record Length (Bytes)                                     2-15
Table 2.3-2. Level 1b IBM 3480 Cartridge Volume (Minutes/Cartridge).                 2-16
Table 3.0.1-1. Spectral band widths (micrometers) of the AVHRR.                       3-1
Table 3.1.2.1-1. Format of GAC data record (implemented November 15, 1994).           3-3
Table 3.1.2.1-2. Format of quality indicators.                                        3-4
Table 3.1.2.1-3. Format of unpacked GAC video data (five channels).                   3-8
Table 3.1.2.1-4. HRPT Minor Frame Format.                                             3-8
Table 3.1.2.2.1-1. Format for GAC video data (two channels).                         3-11
Table 3.1.2.2.2-1. 8-bit format for GAC video data (one channel).                    3-11
Table 3.1.2.2.2-2. Output physical record length for GAC (in bytes).                 3-12
Table 3.2.2.1-1. Format of LAC/HRPT data record (implemented November 15, 1994).
                                                                                     3-13
Table 3.2.2.1-2. Format of unpacked LAC/HRPT video data (five channels).             3-14
Table 3.2.2.2.1-1. Format for LAC/HRPT video data (one channel).                     3-15
Table 3.2.2.2.2-1. Format for LAC/HRPT video data (one channel).                     3-16
Table 3.2.2.2.2-2. Output physical record length for LAC/HRPT (in bytes).            3-16
Table 3.3.2-1. Pre-launch slopes and intercepts for AVHRR Channels 1 and 2.          3-22
Table 3.3.2-2. Values of W and F for AVHRR Channels 1 and 2.                         3-24
Table 4.0-1. Instrument Parameters for TOVS Sensors.                                  4-1
Table 4.1.1-1. Typical HIRS/2 Channel Characteristics.                                4-3
Table 4.1.2.1-1. Format of HIRS/2 Data Record.                                        4-4
Table 4.1.2.1-2. Format of the HIRS/2 Scan Quality Information.                       4-4
Table 4.1.2.1-3. Order of the HIRS/2 calibration coefficients                         4-5
Table 4.1.2.1-4. Format of TIP HIRS/2 data output for one scan.                       4-7
Table 4.1.2.1-5. HIRS/2 minor frame quality field format.                             4-9
Table 4.1.2.1-6. Format for unpacked full copy HIRS/2 data.                          4-10
Table 4.1.2.2-1. Format of the HIRS/2 channel data for two-channel select.           4-11
Table 4.2.1-1. Cell pressures of the SSU channels.                                   4-11
Table 4.2.2.1-1. Format of SSU data.                                                 4-12
Table 4.2.2.1-2. Format of the SSU scan quality information.                         4-13
Table 4.2.2.1-3. Storage of SSU calibration coefficients.                            4-14
Table 4.2.2.1-4. Format of each 60-byte group of SSU data                            4-15
Table 4.2.2.1-5. Definition of the scan position quality for SSU data.               4-15
Table 4.2.2.1-6. Format of unpacked full copy SSU data.                              4-16
Table 4.2.2.2-1. Format of SSU data field when Channels 2 and 3 are selected.        4-17
Table 4.3.2.1-1. Format of MSU Data                                                  4-18
Table 4.3.2.1-2. Format of the MSU scan quality bytes.                               4-18
Table 4.3.2.1-3. Order of MSU calibration coefficients.                              4-19
Table 4.3.2.1-4. Format of MSU data.                                                 4-20
Table 4.3.2.1-5. Typical format for all MSU words (except scan position-line count). 4-21
Table 4.3.2.1-6. Format of MSU scan position - line count (Word 7).                  4-21
Table 4.3.2.1-7. Format of the MSU scan position quality                             4-22
Table 4.3.2.1-8. Unpacked format for full copy MSU data (channel data field).        4-22
Table 4.3.2.2-1. Format of MSU data field if Channels 1 and 4 are selected.          4-23
Table 5.0-1. TOVS Sounding Products on CCT                                            5-2



                                        xiv         NOAA POD Guide - Jan. 2002 Revisionxiv
Table 5.0-2. Sea Surface Temperature Products                                      5-3
Table 5.0-3. Mapped/Gridded AVHRR Product                                          5-3
Table 5.0-4. Radiation Budget Products                                             5-4
Table 5.0-5. SBUV/2 Ozone Products                                                 5-6
Table 5.1.1-1. Directory Information Element                                       5-8
Table 5.1.1-2. Data Directory Element                                              5-9
Table 5.1.1-3. Time Category                                                       5-9
Table 5.1.1-4. NMC/NESDIS Documentation Format                                    5-11
Table 5.1.1-5. NMC/NESDIS Sounding Products/Information Format                    5-12
Table 5.1.1-6. Variables that Comprise ICC                                        5-13
Table 5.1.1-7. Variables that Comprise METREC.                                    5-15
Table 5.1.1.1-1. General Structure of the TOVS Quality Information File           5-16
Table 5.1.1.1-2. Format of the Housekeeping Record for the TOVS Quality Information
File.                                                                             5-16
Table 5.1.1.1-3. Format of Directory Record for the TOVS Quality Information File 5-16
Table 5.1.1.1-4. Format of the Data Record for TOVS Quality Information File.     5-17
Table 5.1.1.1-5. Format of TOVS Quality Information Data Records                  5-17
Table 5.1.2-1. Format of New TOVS Sounding Product Data Record.                   5-19
Table 5.1.2-2. Variables that Comprise ICC                                        5-22
Table 5.1.2-3. Variables that Comprise MR                                         5-23
Table 5.1.2.1-1. Format of the Housekeeping Record                                5-24
Table 5.1.2.1-2. Format of the Directory Record                                   5-25
Table 5.1.2.1-3. Format of New TOVS Quality Information Record                    5-25
Table 5.2-1. Format of the SST Header File                                        5-27
Table 5.2.1-1. Areas of 50-km Gridded SST Fields after August 1, 1986.            5-30
Table 5.2.1-2. Areas of 14-km Gridded SST Fields                                  5-31
Table 5.2.1.1-1. Format of the Directory Record for the SST Field File.           5-32
Table 5.2.1.2-1. Format of the Field Documentation Record                         5-33
Table 5.2.1.3-1. Format of the Parameters in the Grid Intersection.               5-37
Table 5.2.1.3-2. Format of the Latitudinal Row Identifier                         5-38
Table 5.2.2.1-1. Format of the Block Directory for the Seven Day SST Observation File.
                                                                                  5-41
Table 5.2.2.1-2. Format of the Subblock Directory                                 5-42
Table 5.2.2.1-3. Format of the Observation Unit                                   5-43
Table 5.2.2.1-4. Record structure of the Seven Day SST Observation File.          5-44
Table 5.2.2.1-5. SST Observation Types                                            5-44
Table 5.2.2.1-6. SST Observation Source Codes                                     5-46
Table 5.2.2.2-1. Format of the Block Directory Record.                            5-47
Table 5.2.2.2-2. Format of Observation Data Record                                5-48
Table 5.2.2.2-3. Format of the Eight Day SST Observation Unit                     5-49
Table 5.2.3-1. Format of Monthly Mean Data Field                                  5-51
Table 5.3.1-1. File Structure of the Mapped GAC (Polar Stereographic) Tapes       5-52
Table 5.3.1-2. Format of the Documentation Record.                                5-54
Table 5.3.1.1-1. General Structure of the Polar Stereographic KLM Master Map
cartridge                                                                         5-55
Table 5.3.1.1-2. Format of Documentation Record for Polar Stereographic KLM Master



                                        xv         NOAA POD Guide - Jan. 2002 Revisionxv
Map Data                                                                           5-56
Table 5.3.2-1. File Structure of Mapped GAC Data (Mercator                         5-61
Table 5.3.2.1-1. General Structure of the Mercator KLM Master Map Cartridge.       5-62
Table 5.4.1.1-1. Record Length for First Three Data Arrays in the Old Monthly Heat
Budget Data                                                                        5-65
Table 5.4.1.1-2. Documentation for the Polar Stereographic Arrays                  5-66
Table 5.4.1.1-3. Documentation for the 2.5 x 2.5 Degree Mercator Arrays            5-67
Table 5.4.1.2-1. Documentation for the Monthly Polar Stereographic Arrays.         5-69
Table 5.4.1.2-2. Documentation in the Monthly 2.5 x 2.5 Degree Mercator Arrays. 5-69
Table 5.4.1.2-3. Blocking of Data for the Monthly Radiation Budget                 5-71
Table 5.4.2-1. Documentation in the Seasonal Polar Stereographic arrays.           5-73
Table 5.4.2-2. Documentation in the Seasonal 144 x 72 Mercator Arrays.             5-74
Table 5.4.2.1-1. Format of documentation for the 144 x 72 Mercator Arrays          5-75
Table 5.4.3.1-1. Format of Documentation for the 144 x 72 Mercator Arrays          5-76
Table 5.4.3.2.1-1. Documentation and Data Values for the Poles for Each Array.     5-77
Table 5.4.3.2.2-1. Documentation in Polar Stereographic Projection.                5-79
Table A-1. Subroutines IJTOLL and LLTOIJ argument list.                             A-1
Table C-1. Field Station Header Record (ASCII).                                     C-1
Table C-2. Field Station Data Record.                                               C-2
Table D-1. Missing TIROS-N datasets between November 19 - December 20, 1979. D-2
Table D-2. Times of noisy data between July 24-28, 1989.                         D-21
Table K-1. Format of GAC Data Record before September 8, 1992.                      K-1
Table K-2. Format of LAC/HRPT Data Record before September 8, 1992                  K-1
Table K-3. Format of Quality Indicators before September 8, 1994.                   K-1
Table K-4. Format of Dataset Header Record before September 8, 1992.                K-2
Table L-1. Format of the AVHRR dataset header record between October 21, 1992 and
November 15, 1994.                                                                  L-1
Table L-2. Format of the GAC data record between October 21, 1992 and November 15,
1994.                                                                               L-2
Table L-3. Format of the LAC/HRPT data records between October 21, 1992 and
November 15, 1994.                                                                  L-3




                                       xvi         NOAA POD Guide - Jan. 2002 Revisionxvi
1.0            Polar Orbiter System Description

The Satellite Services Branch (SSB) of the National Climatic Data Center, under the auspices of
the National Environmental Satellite, Data, and Information Service (NESDIS), has established a
digital archive of data collected from the current generation of NOAA operational polar orbiting
satellites. This series of satellites commenced with TIROS-N (launched in October 1978) and
continued with NOAA-A (launched in June 1979 and renamed NOAA-6), NOAA-C (launched
in June 1981 and renamed NOAA-7), NOAA-E (launched in March 1983 and renamed NOAA-
8), NOAA-F (launched in December 1984 and renamed NOAA-9), NOAA-G (launched in
September 1986 and renamed NOAA-10), NOAA-H (launched in September 1988 and renamed
NOAA-11), NOAA-D (launched in May 1991 and renamed NOAA-12), NOAA-I (launched in
August 1993 and renamed NOAA-13) and NOAA-J (launched in December 1994 and renamed
NOAA-14). This series of satellites (TIROS-N and NOAA-6 through NOAA-14) will
henceforth be referred to in this document as the TIROS-N series. [Technically, TIROS-N
through NOAA-D are called the TIROS-N series and NOAA-E through -N= are called the
TIROS ATN series (Advanced TIROS-N).] This complete TIROS series will eventually include
NOAA-A through -N=. However, this document covers only the TIROS-N, NOAA-6 through
NOAA-14 satellites.

This document can be found on the Internet at the following Uniform Resource Locator (URL):
http://www2.ncdc.noaa.gov/docs/. Also, the document is available in both WordPerfect 6.1 and
Postscript for downloading through ftp (file transfer protocol) at:
ftp2.ncdc.noaa.gov/pub/doc/podguide/.

This section describes the characteristics of the TIROS-N series instruments, orbits, and data.
Section 1.1 summarizes the instrument characteristics and general properties of the orbit.
Section 1.2 contains specific information regarding the orbits, such as Brouwer mean orbital
elements and how to make a "spinner". Section 1.3 contains information on the procedures for
scheduling high resolution LAC (Local Area Coverage) AVHRR data over a specific area of
interest. Section 1.4 provides specific information for each satellite, including operational date
ranges, abnormalities, AVHRR and TOVS spectral responses, HIRS/2 thermal band-correction
coefficients and AVHRR central wave numbers.

1.1            System Summary

This section summarizes the characteristics of the NOAA polar orbiter satellite instruments and
properties of the satellite orbit. A detailed description of the NOAA Polar Orbiter
instrumentation may be found in NOAA Technical Memoranda NESS 95 and 116, entitled
respectively, The TIROS-N/NOAA-A-G Satellite Series, and Modified Version of the TIROS-
N/NOAA A-G Satellite Series (NOAA E-J) - Advanced TIROS-N (ATN). These documents are
available from SSB.

The satellite system includes the following instrument package:

       AVHRR - Advanced Very High Resolution Radiometer, from which is obtained:

                                                     1-1           NOAA POD GUIDE - 11/98 Revision
                       a. HRPT - High Resolution Direct Readout AVHRR
                       b. LAC - Recorded HRPT AVHRR
                       c. GAC - Reduced Resolution Recorded AVHRR

       TOVS - TIROS Operational Vertical Sounder, which includes:
                  a. MSU - Microwave Sounding Unit
                  b. SSU - Stratospheric Sounding Unit
                  c. HIRS/2 - High Resolution Infrared Radiation Sounder/2

The TIROS-N/NOAA A-G (6-10) series of satellites have been modified to add payload capacity
without changing the basic environmental mission of the series. Seven additional satellites
(NOAA-H, -I, -J, -K, -L, -M, -N and -N=) were added to the initial procurement to extend the
lifetime of the program to the end of the century. Incrementally added to the payload were a
Search and Rescue Demonstration System (SAR), an Earth Radiation Budget Experiment
(ERBE) flown on NOAA-9 and NOAA-10 only, and an operational Solar Backscatter Ultraviolet
Radiometer (SBUV/2) to monitor the distribution of ozone in the atmosphere (flown on NOAA-
9, -11, -13 and -14).

The NOAA-E through -N= spacecraft, also called the Advanced TIROS-N (ATN), are similar to
the NOAA-A through -D satellites that preceded them with the exception that the Equipment
Support Module has been enlarged to allow integration of new payloads. A change from the
TIROS-N through NOAA-8 spacecraft is that the spare word locations of the low bit rate data
system TIROS Information Processor (TIP) is used for special instruments such as the ERBE and
SBUV/2. The SAR system will be independent, utilizing a special frequency for transmission of
data to the ground.

As the satellite orbits the Earth, data are both broadcast continually (direct readout mode) and
recorded on board for later playback. NOAA/NESDIS operates two Command and Data
Acquisition (CDA) stations, one in Wallops Island, Virginia and one in Fairbanks, Alaska
(formerly Gilmore Creek before 1984), to receive both recorded and direct readout
environmental data from the satellite and send these data to Suitland, Maryland, via satellite
relay. However, during two (sometimes three) sequential orbits of the Earth, the satellite
remains out of contact with any of these sites.

The NOAA/NESDIS ground stations in Wallops, VA and Fairbanks, AK receive Direct Readout
High Resolution Picture Transmission (HRPT) data. Fairbanks maintains a 90-day rotating pool
of these data, while Wallops keeps a 60-day pool. As of January 1, 1997, both CDA stations
reduced their rotating pools to 30 days. The data are in Field Station format which is described
in Appendix C. These data may be ordered through SSB. The Field Station data do not have
appended Earth location and calibration information, and are 8-bit precision rather than 10-
bit precision. The amount of HRPT data received during one pass of the satellite over the ground
station is limited to the acquisition range of the station. A satellite pass directly over an antenna
site will be within view of that antenna (horizon to horizon) for about 15.5 minutes when the
satellite is at 833 km and 16 minutes when it is at 870 km. Figures 1.1-1 and 1.1-2 depict the


                                                      1-2          NOAA POD GUIDE - 11/98 Revision
overall HRPT coverage from each of the NESDIS ground stations over the Northern and
Southern hemispheres, respectively.

In addition to providing direct readout, the TIROS-N series satellites carry five digital tape
recorders, each with a single electronic module and dual tape transport, to record data for
subsequent transmission through the CDA to the data processing facility. Each transport has the
capacity to record one of the following:

       1)      115 minutes (slightly more than a full orbit) of GAC with embedded TIP data.
               (TIROS Information Processor is the on board computer system that formats the
               sensor data for transmission. TIP includes TOVS and auxiliary data.)

       2)      Eleven and one half minutes of HRPT data (called LAC when recorded), or

       3)      230 minutes of TIP data only (called stored TIP).

Between October 1978 and April 11, 1985, direct readout HRPT and recorded GAC, LAC, and
TIP data were ingested by NESDIS computers and stored temporarily on staging disks used as
work space and for interfacing these computers with the NESDIS Terabit Memory (TBM) mass
storage system. The ingested data were then retrieved from disk storage on a time-available
basis, processed to Level 1b format (which included appending of Earth location and calibration
information) and returned to the disks for subsequent transfer to the TBM for NESDIS product
processing and the SSB archive.

On April 11, 1985, NESDIS abandoned the TBM system as a means of storing ingested polar
orbiter data. Over the years, SSB=s hardware complement has changed with advancing
technology, but the corresponding media changes remain transparent to the satellite data user.

During the period of conversion from TBM tapes, SSB attempted to transfer as much of the data
from TBM tapes as possible (while simultaneously servicing user requests). Priority was given
to recovering the GAC data sets and 88% of these were saved. Similarly, 49% of the TOVS and
6% of the LAC/HRPT were saved. Users should contact SSB for the availability of any Level 1b
data which were ingested between October 1978 and April 1985.




                                                    1-3            NOAA POD GUIDE - 11/98 Revision
Figure 1.1-1. Satellite Track Template- S. H.




                         1-4          NOAA POD GUIDE - 11/98 Revision
                         Figure 1.1-2. Satellite Track Template – N.H.

As mentioned above, Earth location and calibration data are appended to the data as part of the
Level 1b processing. The Earth location data are read from CCTs which contain up to 29 hours
of information. These data are updated every 24 hours. These Earth location tapes (called
GELDS data) were archived by SSB between March 8, 1985 and Sept. 7, 1992. On Sept. 8,
1992, NESDIS/IPD discontinued generating the GELDS data since the data were redundant with
the Level 1b data.

For purposes of clarification, Figure 1.1-3 will be used as the definition of Solar Zenith angle,
local zenith angle, and satellite scan angle. These angles are referred to throughout this guide
and have the relationships shown in the figure.


                                                     1-5           NOAA POD GUIDE - 11/98 Revision
                                Figure 1.1-3. Solar Zenith Angle

1.2            Orbital Information

The TIROS-N series satellites were designed to operate in a near-polar, sun-synchronous orbit.
The orbital period is about 102 minutes which produces 14.1 orbits per day. Because the number
of orbits per day is not an integer, the sub-orbital tracks do not repeat on a daily basis, although
the local solar time of the satellite's passage is essentially unchanged for any latitude.

However, the satellite's orbits drift over time (Price 1991). This drift causes a systematic change
of illumination conditions and local time of observation which is the major source of non-
uniformity in multi-annual satellite time series.

Table 1.2-1 contains the approximate times of the ascending node (northbound Equator crossing)
and the descending node (southbound Equator crossing) in Local Solar Time (LST) for the
TIROS-N series when the satellites were launched. This table also contains the ascending and
descending nodes as of March 1995 for the active satellites.



                                                     1-6           NOAA POD GUIDE - 11/98 Revision
                Table 1.2-1. Ascending and descending node times in LST.
              Ascending Node Descending Node Ascending Node Descending Node
  Satellite      (Launch)           (Launch)            (3/95)             (3/95)
 TIROS-N      1500              0300               n/a                n/a
 NOAA-6       1930              0730               n/a                n/a
 NOAA-7       1430              0230               n/a                n/a
 NOAA-8       1930              0730               n/a                n/a
 NOAA-9       1420              0220               2116               0916
 NOAA-10      1930              0730               1753               0553
 NOAA-11      1330              0130               1723               0523
 NOAA-12      1930              0730               1915               0715
 NOAA-13      1340              0140               n/a                n/a
 NOAA-14      1330              0130               1330               0130

Table 1.2-2 summarizes the important dates for the satellites which have already been launched
from the TIROS-N series. The date range in this table is at best an approximation. There may
be scattered data sets available before or after these dates.

     Table 1.2-2. Launch and data available dates for the TIROS-N series satellites.
     Satellite             Launch Date                          Date Range
 TIROS-N             October 13, 1978            October 19, 1978-January 30, 1980
 NOAA-6              June 27, 1979               June 27, 1979-March 5, 1983
                                                 July 3, 1984-November 16, 1986
 NOAA-B              May 29, 1980                Failed to achieve orbit
 NOAA-7              June 23, 1981               August 19, 1981-June 7, 1986
 NOAA-8              March 28, 1983              June 20, 1983-June 12, 1984
                                                 July 1, 1985-October 31, 1985
 NOAA-9              December 12, 1984           February 25, 1985-November 7, 1988
 NOAA-10             September 17, 1986          November 17, 1986-September 16, 1991
 NOAA-11             September 24, 1988          November 8, 1988-April 11, 1995
 NOAA-12             May 14, 1991                May 14, 1991-present
 NOAA-13             August 9, 1993              August 9, 1993-August 21, 1993
 NOAA-14             December 30, 1994           April 11, 1995-present

SSB has available specific orbital reference information regarding each orbit of the polar
orbiters. This information consists of the orbit number, longitude of ascending and descending
nodes, and height of satellite at each node, and date and local time. SSB routinely receives this
nodal information from SOCC two or three weeks in advance of the actual orbit.

A user may want to know the sub-orbital track and areal coverage available for a polar orbiter.
The following paragraph describes how to make a "spinner" which would show the user this
information. A spinner consists of a base map which is overlaid with a piece of clear acetate
containing the sub-orbital track of the satellite. The acetate track is rotated over the base map as
desired.
                                                      1-7          NOAA POD GUIDE - 11/98 Revision
To make a spinner, the polar-stereographic map of the Northern Hemisphere in Figure 1.1-1
should be mounted on stiff cardboard or similar material. The sub-orbital track and width of the
orbital swath for the TIROS-N series which is shown in Figure 1.2-1 should be traced onto a
piece of clear acetate and overlaid on the base map. Note for Figures 1.2-1 and 1.2-2, the outer
solid lines indicate a 15 degree swath (the actual width of an orbital swath is approximately 25
degrees ). The area under the 15 degree swath contains good, usable data with little or no
distortion at the edges. A small map pin should be inserted through the "x" on the acetate and
into the center (North Pole) of the base map. The numbers indicated on the sub-orbital track are
the minutes after the ascending node. The user need only rotate the acetate around the map base
until the orbital track is over the desired area and read off the ascending node longitude. Or,
conversely, if the orbit number and ascending node longitude are known, then the spinner can be
rotated to the proper longitude and the orbital coverage will be shown as that area covered by the
spinner. Similarly, a Southern Hemisphere spinner can be made using the base map in Figure
1.1-2 and the sub-orbital track in Figure 1.2-2.

Users now have the option of downloading a self-extracting file XTRCTORB.EXE to their PC=s
hard drive. This file generates a program, GNRLORB.EXE and associated files which are the
equivalent of making the spinner described in this section. By inputting the longitude of the
ascending node (which is also available on the same WWW site), GNRLORB will display the
subtrack of a nominal TIROS-N series satellite with marks at five minute intervals from the
ascending node and the limits of an AVHRR scan on a choice of map bases: 1) rectangular equal
spaced projection from 70S to 70N latitude; 2) Northern Hemisphere Polar Stereographic
projection; and 3) Southern Hemisphere Polar Stereographic projection. Users may access this
software from NOAA/NESDIS= Product Systems Branch (PSB) Home Page which has a URL
of: http://psbsgi1.nesdis.noaa.gov:8080/ISB/NAVIGATION/navpage.html. Users should click
on the AGraphical Orbit Locator@ to initiate the ftp download process. This same site also
contains an overview of the NESDIS polar earth location process, polar satellite equator crossing
information and clock drift files for polar satellites, as well as links to TBUS information and the
Brouwer/Lyddane Software package.

Another excellent source of satellite navigation information is located at the NOAA Satellite
Information System (NOAASIS) Internet site which has the following URL:
http://140.90.207.25:8080/noaasis.html. Users should click on the ANavigation@ button to
access TBUS bulletins, equator crossings, orbital elements and two line elements for both GOES
and POES satellites. Also included is the navigation summary for the GOES satellites and the
Monthly Predict elements for the POES. Further information on NOAASIS is included in
Appendix G




                                                     1-8           NOAA POD GUIDE - 11/98 Revision
Figure 1.2-1 AVHRR Orbital SwathTemplate




                      1-9        NOAA POD GUIDE - 11/98 Revision
Figure 1.2-2. AVHRR Orbital Swath Template




                      1-10        NOAA POD GUIDE - 11/98 Revision
The United States Space Command (USSC, formerly NORAD) tracks TIROS-N series satellites
for NESDIS. USSC sends orbital information to NESDIS each day. NESDIS regularly produces
Brouwer mean orbital elements for its polar orbiting satellites and SSB archives them weekly (in
hardcopy form). An example of the Brouwer mean orbital elements for TIROS-N (as of October
24, 1978 at 0000 UTC) is contained in Table 1.2-3.

 Table 1.2-3. Brouwer mean orbital elements for TIROS-N on Oct. 24, 1978 at 0000 UTC.
                  Parameter                                   Value
 Semi-Major Axis                             7231.8505 km
 Eccentricity                                0.0011
 Inclination                                 98.9127 degrees
 Right ascension of ascending node           257.4741 degrees
 Anomalistic period                          102.0065 minutes
 Argument of perigee                         253.5599 degrees
 Mean anomaly                                126.4732
 Height of perigee                           845.67 km
 Height of apogee                            861.62 km

SOCC began recording TBUS (APT predict bulletin) messages on magnetic tape beginning on
June 1, 1990. These TBUS messages contain information about each operational polar orbiter
satellite. Specifically, TBUS Part IV contains the Brouwer mean elements which can be used in
a stand alone Brouwer-Lyddane orbit prediction package to determine orbit position information
at any time t-t0 where t0 represents the time of the Brouwer mean elements in Part IV and t
represents the user request time. The Brouwer-Lyddane algorithm is an analytical solution of
satellite motion for a simplified disturbing potential field limited to zonal harmonic coefficients
for J2 through J5. Lyddane modified Brouwer's formulation to obtain algorithms applicable for
zero eccentricity and zero inclination. This stand alone software package is included in
Appendix F. Users may also request TBUS messages in hardcopy form from SSB.

Based on the information in Table 1.2-3, orbital reference information (ephemeris data) for the
first operational TIROS-N orbit on November 1, 1978 is given in Table 1.2-4.

   Table 1.2-4. Orbital reference information (Ephemeris data) for TIROS-N Orbit 262.
                  Parameter                                     Value
 Satellite                                     TIROS-N
 Orbit no.                                     262
 Date/time                                     0042.70
 Longitude of ascending node                   145.56 W
 Nodal period                                  102.1241 minutes
 Increment between orbits                      25.53 degrees

The ephemeris data is updated regularly and maintained on file (hardcopy) at SSB. Since June 1,
1992, SSB has also maintained an archive of ephemeris data containing 4-line elements and the
PSCEAR initialization reports that IPD and Satellite Operations Control Center (SOCC) use to
                                                    1-11           NOAA POD GUIDE - 11/98 Revision
precisely locate each NOAA operational polar orbiting spacecraft for navigational purposes.
These data are available from SSB.

The 4-line elements are generated by the NAVY's U.S. Space Command (USSC, formerly
NORAD) and are transmitted to SOCC around 0000Z each day. IPD uses them to reinitialize or
update the user ephemeris files each day. The 4-line elements contain the following parameters:
the satellite ID, epoch time, epoch revolution number, the x,y,z components of the position and
velocity vectors (Cartesian coordinates), ballistic coefficients, daily solar flux, average solar flux
for 90 days, planetary magnetic index, drag modulation coefficient, radiation pressure
coefficient, time of ascending node, revolution number at time of ascending node, the universal
time correction and the universal time correction rate.

The PSCEAR initialization reports contain information from the User Ephemeris Files (UEF)
header. The PSCEAR reports contain osculating Keplerian elements at epoch, the inertial
Cartesian elements, the Brouwer mean elements at epoch, the anomalistic and nodal periods,
orbit number at epoch, plus the first time derivatives of: the right ascension of the ascending
node, argument of perigee and the mean anomaly. Contact SSB (see Section 6) to order these
ephemeris data.

Users may access NOAA's Electronic Bulletin Board (NOAA.SIS) for information such as
weekly HRPT/LAC coverage areas, TBUS messages, USSC 2-line elements (weekly), Keplerian
orbital elements (weekly), recorder schedules (daily), weekly spacecraft events, polar status
reports (monthly), and general information regarding NOAA's satellites. Much of the same
information contained in NOAA.SIS resides on the Internet at URL:
psbsgi1.nesdis.noaa.gov:8080/noaasis.html. See Appendix G for specific procedures for
telecommunication access to NOAA.SIS.

1.3            Procedure for Scheduling AVHRR LAC Data

Users may request scheduling of Local Area Coverage (LAC) data which are recorded outside
the direct readout range of Wallops Island, Virginia or Fairbanks, Alaska. Because recorder
space and transmission time must be shared by many requestors, requests must be received at
least one month prior to the data acquisition period. Requests will be considered on a first-come,
first-served basis, and according to the following priority considerations:

       1.      National emergencies, as specified in the various national emergency plans

       2.      Situations where human life is in immediate danger (i.e., search and rescue
               operations)

       3.      U.S. strategic requirements

       4.      Commercial requirements

       5.      Scientific investigations and studies

                                                       1-12         NOAA POD GUIDE - 11/98 Revision
       6.     Other miscellaneous activities

Requests must also be accompanied by the following:

       a.     Brief description of application

       b.     Geographical area (i.e., East Greenland, Korea Straits, etc.)

       c.     Latitude and longitude coordinates bounding the area of interest

       d.     Desired frequency of coverage (i.e., once weekly, etc.)

       e.     Spectral channels required for image processing - Channel 1 or 2 = visible;
              Channel 3, 4, or 5 = infrared. Include range of expected brightness values or
              temperatures for image enhancement purposes.

       f.     Type of data - digital data available on computer compatible tape (CCT), and/or
              analog data, available as photographic prints.

       g.     Beginning and ending dates of the study period.

       h.     Satellite preference: NOAA-12 - daylight descending, nighttime ascending;
              NOAA-14 - daylight ascending, nighttime descending.

       i.     Name, address, and telephone number of requestor.

Failure to provide this information at the time of the request may cause a delay in scheduling of
the LAC data. Requests for AVHRR LAC data may be emailed (preferred) or if phoned in, must
be followed by written documentation. Submit requests to:

Mr.Tom Snell
NOAA/NESDIS/SOCC
Federal Office Building #4, Room 0220
Suitland, MD 20746-1701
Phone #: 301-457-5208
Fax #: 301-457-5175
Email: tsnell@nesdis.noaa.gov

Every effort is made to accommodate each request, for example, by combining requests of
overlapping areas. However, because the number of requests for LAC coverage always
surpasses scheduling resources, NESDIS does not guarantee complete or even partial fulfillment
of LAC requirements. When the lack of scheduling resources severely limits the acquisition of
LAC coverage, requestors will be notified by SOCC LAC scheduling personnel. Users are not
charged a fee for scheduling services.


                                                   1-13          NOAA POD GUIDE - 11/98 Revision
Users should be aware that a request for LAC scheduling with SOCC is not an implicit request
for data. Users must also contact SSB and meet all prepayment requirements before the actual
processing of a data request can begin (see Section 6 for more details on ordering products from
SSB).

1.4            Miscellaneous Parameters for the Polar Orbiter Satellites

This section provides specific information for each satellite. Each subsection contains a
satellite's operational date range(s), any abnormalities associated with the satellite, tables for
TOVS channel spectral response and HIRS/2 thermal band-correction coefficients, tables for
AVHRR infrared channel central wave numbers as a function of temperature, and the spectral
response curves for the AVHRR instrument. Many of these parameters are needed for
calibration purposes.

Users should be aware that AVHRR Channel 3 data on TIROS-N series spacecraft have been
very noisy due to an instrument problem and may be unusable at times.

1.4.1          TIROS-N

Operational dates: October 19, 1978 to January 30, 1980

Afternoon orbit: 1500 LST ascending node, 0300 LST descending node

AVHRR instrument: 4 channels

Spacecraft ID: 1

Table 1.4.1-1 contains the central wave numbers for the AVHRR IR channels for TIROS-N.
Table 1.4.1-2 contains the TOVS channel spectral response and HIRS/2 thermal band-correction
coefficients for TIROS-N. Non-linearity errors for TIROS-N AVHRR Channel 4 are contained
in Table 1.4.1-3. Table 1.4.1-4 contains values of the corrected radiance of space, Nsp (which
includes the non-linearity correction) for the TIROS-N AVHRR IR channels.

Figures 1.4.1-1 through 1.4.1-4 contain the spectral response curves for the TIROS-N AVHRR
channels 1 through 4, respectively.

         Table 1.4.1-1. TIROS-N Central Wave Numbers for AVHRR IR Channels.
      Temperature Range (K)           Ch. 3 (cm-1)             Ch. 4 (cm-1)
            180-225                     2631.81                  911.13
            225-275                     2635.15                  911.54
            275-320                     2638.05                  912.01




                                                     1-14           NOAA POD GUIDE - 11/98 Revision
Table 1.4.1-2. TIROS-N TOVS Channel Spectral Response and HIRS/2 Thermal Band-
                             Correction Coefficients.
                                                                 HIRS/2 Band-
                                                                   Correction
                                                                   Coefficients
Instrument Channel #      Central Wave #       Description        b            c
HIRS/2        1         668.00 cm-1          15 micrometers 0.047         0.99986
              2         679.23 cm-1          CO2 Band        0.067        0.99979
              3         691.12 cm-1          CO2 Band        0.131        0.99962
              4         703.56 cm-1          CO2 Band        0.015        0.99991
              5         716.05 cm-1          CO2 Band        0.010        0.99993
              6         732.38 cm-1          CO2 Band        0.092        0.99974
              7         748.27 cm-1          CO2 Band        -0.101       1.00015
              8         897.71 cm-1          Window          -0.252       1.00013
              9         1027.87 cm-1         Ozone           0.118        0.99978
              10        1217.10 cm-1         Water Vapor     -0.132       0.99908
              11        1363.69 cm-1         Water Vapor     0.136        0.99982
              12        1484.35 cm-1         Water Vapor     0.424        0.99948
              13        2190.43 cm-1         4.3 micrometers -0.015       0.99969
              14        2212.65 cm-1         CO2 Band        0.041        1.00011
              15        2240.15 cm-1         CO2 Band        0.074        1.00032
              16        2276.27 cm-1         CO2 Band        0.143        1.00057
              17        2360.63 cm-1         CO2 Band        0.060        1.00025
              18        2511.95 cm-1         Window          0.110        1.00020
              19        2671.18 cm-1         Window          0.650        1.00175
              20        14367.00 cm-1        Visible         n/a          n/a
                                             Window
MSU           1         1.6778 cm-1
              2         1.7926 cm-1
              3         1.8333 cm-1
              4         1.9330 cm-1
SSU           1         669.988 cm-1/15
                        mb
              2         669.628 cm-1/5 mb
              3         669.357 cm-1/1.5
                        mb

                Table 1.4.1-3. Corrected values for TIROS-N Nsp.
               Channel                              Nsp (mW/(m2-sr-cm-1))
                  3                                          0.0
                  4                                        -1.151


                                          1-15         NOAA POD GUIDE - 11/98 Revision
             Table 1.4.1-4. Non-linearity errors for TIROS-N Channel 4.
         Target temperature (K)                             Error (K)
                  304.9                                       1.25
                  294.9                                       0.98
                  285.0                                        0.0
                  275.1                                       -0.03
                  264.9                                       -0.08
                  255.1                                       -0.10
                  234.9                                       -0.75
                  224.9                                       -0.95
                  204.9                                       -1.67
                   0.0                                         0.0

Table 1.4.1-5. PRT Coefficients for all Instruments on TIROS-N (from NESS 107)
                                      AVHRR
                      PRT counts to Temperature Coefficients
   PRT                  a0               a1                 a2                  a3
     1                277.73          0.047752           8.29E-6               0.0
     2                277.41          0.046637          11.01E-6               0.0
     3                277.12          0.045188          14.77E-6               0.0
     4                277.42          0.046387          10.59E-6               0.0
                              PRT Weighting Factors
       b1                     b2                    b3                       b4
      0.25                   0.25                  0.25                     0.25
            Radiance of Space (Nsp) Including Nonlinearity Correction
                Channel                               Nsp(mW/sr-m2-cm-1)
                    3                                            0.0
                    4                                          -1.151
                    5                                          -1.151
                                        HIRS
                   IWT PRT Count to Temperature Coefficients
  PRT              a0             a1            a2               a3              a4
   1            301.4624     6.51558E-03 9.15434E-08 4.71066E-11 6.83373E-16
   2            301.3504     6.51439E-03 9.15816E-08 4.70945E-11 6.85893E-16
   3            301.4250     6.51738E-03 9.16252E-08 4.41175E-11 6.87601E-16
   4            301.4035     6.52364E-03 9.00018E-08 4.71042E-11 6.61634E-16
                                        SSU
                      PRT Count to Temperature Coefficients
           a0                            a1                              a2
        285.082                      4.5542E-03                      9.6285E-09
                      Thermistor to Temperature Coefficients
       b0                     b1                    b2                       b3
    375.969                -203.161              179.13                    -85.16
       c0                      c1                   c2                       c3
                                              1-16         NOAA POD GUIDE - 11/98 Revision
375.969            -203.161              179.13              -85.16
                               MSU
            PRT Resistance to Temperature Coefficients
            K0                                      495.6
            K1                                      107.8
             PRT Resistance to Temperature coefficients
                      e0                   e1                  e2
  1A                29.10                .42596            .3187E-04
  2A                27.55                .42787            .3185E-04
  1B                29.05                .42710            .3206E-04
  2B                28.95                .42836            .3175E-04
                      Radiance of Space (Nsp)
          Channel                            Nsp(mW/sr-m2-cm-1)
             1                                    0.000086
             2                                    0.000096
             3                                    0.000084
             4                                    0.000092




   Figure 1.4.1-1. Spectral Response Curve TIROS-N AVHRR Channel 1.




                                       1-17        NOAA POD GUIDE - 11/98 Revision
Figure 1.4.1-2. Spectral Response Curve TIROS-N AVHRR Channel 2.




                                  1-18        NOAA POD GUIDE - 11/98 Revision
Figure 1.4.1-3. Spectral Response Curve TIROS-N AVHRR Channel 3.




                                  1-19        NOAA POD GUIDE - 11/98 Revision
Figure 1.4.1-4. Spectral Response Curve TIROS-N AVHRR Channel 4.




                                  1-20        NOAA POD GUIDE - 11/98 Revision
1.4.2            NOAA-6

Operational dates:   June 27, 1979 - March 5, 1983
                     July 3, 1984 - November 16, 1986

Morning orbit:       1930 LST ascending node, 0730 LST descending node

AVHRR instrument: 4 channels

Spacecraft ID:       2

Abnormalities:       NOAA-6 was reactivated on July 3, 1984 to collect selected LAC/HRPT
                     data because of the loss of NOAA-8.

Table 1.4.2-1 contains the central wave numbers for the AVHRR IR channels for NOAA-6.
Table 1.4.2-2 contains the TOVS channel spectral response and HIRS/2 thermal band-correction
coefficients for NOAA-6. Non-linearity errors for NOAA-6 AVHRR Channel 4 are contained in
Table 1.4.2-3. Table 1.4.2-4 contains values of the corrected radiance of space, Nsp (which
includes the non-linearity correction) for the NOAA-6 AVHRR IR channels.

Figures 1.4.2-1 through 1.4.2-4 contain the spectral response curves for NOAA-6 AVHRR
channels 1 through 4, respectively.

 Table 1.4.2-1. NOAA-6 Central Wave Numbers for AVHRR IR Channels.
 Temperature Range (K)      Ch. 3 (cm-1)             Ch. 4 (cm-1)
           180-225                    2649.90                  910.72
           225-275                    2653.90                  911.41
           275-320                    2658.05                  912.14

  Table 1.4.2-2. NOAA-6 TOVS Channel Spectral Response and HIRS/2 Thermal Band-
                              Correction Coefficients.
                                                                 HIRS/2 Band-
                                                                   Correction
                                                                   Coefficients
 Instrument Channel #      Central Wave #       Description       b            c
 HIRS/2        1         668.02 cm-1          15 micrometers 0.025        0.99992
               2         679.94 cm-1          CO2 Band       0.151        0.99900
               3         690.44 cm-1          CO2 Band       0.115        0.99970
               4         704.69 cm-1          CO2 Band       0.041        0.99984
               5         717.43 cm-1          CO2 Band       -0.035       1.00000
               6         732.47 cm-1          CO2 Band       0.066        0.99980
               7         748.48 cm-1          CO2 Band       -0.101       1.00012
               8         900.64 cm-1          Window         0.185        0.99961

                                                1-21         NOAA POD GUIDE - 11/98 Revision
          9           1029.48 cm-1          Ozone             0.268      0.99990
          10          1217.77 cm-1          Water Vapor       -0.205     0.99877
          11          1368.05 cm-1          Water Vapor       0.073      0.99966
          12          1485.76 cm-1          Water Vapor       0.597      1.00026
          13          2190.60 cm-1          4.3 micrometers   0.022      1.00000
          14          2210.09 cm-1          CO2 Band          -0.001     0.99978
          15          2237.76 cm-1          CO2 Band          0.029      0.99999
          16          2269.43 cm-1          CO2 Band          0.015      0.99991
          17          2360.42 cm-1          CO2 Band          0.011      0.99984
          18          2514.97 cm-1          Window            0.051      0.99985
          19          2654.58 cm-1          Window            0.482      1.00042
          20          14453.14 cm-1         Visible indow     n/a        n/a
MSU       1           1.6778 cm-1
          2           1.7926 cm-1
          3           1.8333 cm-1
          4           1.9330 cm-1
SSU       1           669.998 cm-1/15
                      mb
          2           669.620 cm-1/5 mb
          3           669.357 cm-1/1.5
                      mb

          Table 1.4.2-3. Non-linearity errors for NOAA-6 Channel 4.
      Target temperature (K)                            Error (K)
                315                                        0.8
                305                                        0.5
                295                                        0.3
                285                                        0.0
                275                                       -0.4
                255                                       -0.8
                245                                       -1.4
                235                                       -1.4
                225                                       -2.0
                215                                       -2.0
                205                                       -2.8
                195                                       -2.6
                185                                       -2.0
                 0                                         0.0




                                          1-22        NOAA POD GUIDE - 11/98 Revision
                  Table 1.4.2-4. Corrected values for NOAA-6 Nsp.
                 Channel                              Nsp (mW/(m2-sr-cm-1))
                    3                                          0.0
                    4                                       -2.18222

Table 1.4.2-5. PRT Coefficients for all Instruments on NOAA-6 (from NESS 107)
                                       AVHRR
                      PRT counts to Temperature Coefficients
PRT             a0               a1                 a2               a3          a4
  1        278.3863101 3.1620496E-2          4.9133034E-5           0.0          0.0
  2        278.2352898 3.0384174E-2          5.1555794E-5           0.0          0.0
  3        278.0691316 4.2528998R-2          1.6065146E-5           0.0          0.0
  4        277.9288372 4.0905453E-2          1.9771519E-5           0.0          0.0
                             PRT Weighting Factors
       b1                    b2                      b3                     b4
      0.25                  0.25                    0.25                   0.25
           Radiance of Space (Nsp) Including Nonlinearity Correction
               Channel                                 Nsp(mW/sr-m2-cm-1)
                   3                                           0.0
                   4                                        -2.18222
                   5                                        -2.18222
                                        HIRS
                  IWT PRT Count to Temperature Coefficients
 PRT               a0             a1             a2             a3              a4
    1          301.3386     6.50696E-03 8.61837E-08 4.78285E-11 1.16300E-15
    2          301.3680     6.49600E-03 8.67631E-08 4.80667E-11 1.09312E-15
    3          301.4294     6.49187E-03 8.57490E-08 4.77480E-11 1.15969E-15
    4          301.3820     6.49980E-03 8.60846E-08 4.77490E-11 1.60800E-15
                                         SSU
                      PRT Count to Temperature Coefficients
           a0                             a1                            a2
       284.1571                      4.75532E-03                   6.34256E-09
                      Thermistor to Temperature Coefficients
       b0                    b1                      b2                     b3
    375.969               -203.161                179.13                 -85.16
       c0                     c1                     c2                     c3
    375.969               -203.161                179.13                 -85.16
                                        MSU
                   PRT Resistance to Temperature Coefficients
                  K0                                          495.6
                  K1                                          107.8
                    PRT Resistance to Temperature coefficients
                              e0                     e1                     e2
                                              1-23          NOAA POD GUIDE - 11/98 Revision
1A              29.3271             .4254270           .3165629E-04
2A              29.3083             .4260801           .3149910E-04
1B              29.2923             .4261320           .3152410E-04
2B              29.3731             .4255765           .3176020E-04
                   Radiance of Space (Nsp)
      Channel                             Nsp(mW/sr-m2-cm-1)
         1                                     0.000086
         2                                     0.000096
         3                                     0.000084
         4                                     0.000092




 Figure 1.4.2-1. Spectral Response Curve NOAA-6 AVHRR Channel 1.




                                   1-24         NOAA POD GUIDE - 11/98 Revision
Figure 1.4.2-2. Spectral Response Curve NOAA-6 AVHRR Channel 2.




                                 1-25        NOAA POD GUIDE - 11/98 Revision
Figure 1.4.2-3. Spectral Response Curve NOAA-6 AVHRR Channel 3.




                                 1-26        NOAA POD GUIDE - 11/98 Revision
Figure 1.4.2-4. Spectral Response Curve NOAA-6 AVHRR Channel 4.




                                 1-27        NOAA POD GUIDE - 11/98 Revision
1.4.3            NOAA-7

Operational dates:    August 24, 1981 - February 1, 1985

Afternoon orbit:      1430 LST ascending node, 0230 LST descending node

AVHRR instrument: 5 channels

Spacecraft ID:        4

Table 1.4.3-1 contains the central wave numbers for the AVHRR IR channels for NOAA-7.
Table 1.4.3-2 contains the TOVS channel spectral response and HIRS/2 thermal band-correction
coefficients for NOAA-7. Non-linearity errors for NOAA-7 AVHRR Channels 4 and 5 are
contained in Table 1.4.3-3. Table 1.4.3-4 contains values of the corrected radiance of space, Nsp
(which includes the non-linearity correction) for the NOAA-7 AVHRR IR channels.

Figures 1.4.3-1 through 1.4.3-5 contain the spectral response curves for NOAA-7 AVHRR
Channels 1 through 5, respectively.

      Table 1.4.3-1. NOAA-7 Central Wave Numbers for AVHRR IR Channels.
  Temperature Range (K)  Channel 3 (cm-1)   Channel 4 (cm-1) Channel 5 (cm-1)
        180-225                 n/a             926.20           840.100
        225-275               2670.3            926.80           840.500
        275-320               2671.9            927.22           840.872

  Table 1.4.3-2. NOAA-7 TOVS Channel Spectral Response and HIRS/2 Thermal Band-
                              Correction Coefficients.
                                                                 HIRS/2 Band-
                                                                   Correction
                                                                   Coefficients
 Instrument Channel #      Central Wave #       Description       b            c
 HIRS/2        1         667.92 cm-1          15 micrometers -0.010       1.00001
               2         679.21 cm-1          CO2 Band       0.100        0.99973
               3         691.56 cm-1          CO2 Band       -0.018       0.99997
               4         704.63 cm-1          CO2 Band       0.026        0.99989
               5         717.05 cm-1          CO2 Band       -0.009       0.99995
               6         733.20 cm-1          CO2 Band       -0.081       1.00008
               7         749.20 cm-1          CO2 Band       -0.054       1.00003
               8         898.94 cm-1          Window         0.332        0.99942
               9         1027.38 cm-1         Ozone          0.205        0.99987
               10        1224.89 cm-1         Water Vapor    0.469        0.99994
               11        1363.85 cm-1         Water Vapor    0.114        0.99983
               12        1489.06 cm-1         Water Vapor    0.573        1.00028
                                                   1-28          NOAA POD GUIDE - 11/98 Revision
            13            2183.05 cm-1         4.3 micrometers   0.047      1.00013
            14            2208.28 cm-1         CO2 Band          0.060      1.00028
            15            2239.84 cm-1         CO2 Band          0.021      0.99993
            16            2271.33 cm-1         CO2 Band          0.032      1.00008
            17            2357.55 cm-1         CO2 Band          0.032      1.00005
            18            2512.83 cm-1         Window            0.026      0.99968
            19            2663.79 cm-1         Window            0.637      1.00171
            20            14453.14 cm-1        Visible           n/a        n/a
                                               Window
            1             1.6779 cm-1
MSU         2             1.7927 cm-1
            3             1.8337 cm-1
            4             1.9331 cm-1
            1             669.988 cm-1/15 mb
SSU         2             669.628 cm-1/5 mb
            3             669.357 cm-1/1.5
                          mb

         Table 1.4.3-3. Non-linearity errors for NOAA-7 Channels 4 and 5.
 Target temperature (K)         Channel 4 Error (K)       Channel 5 Error (K)
           315                          1.66                       1.08
           305                          1.05                       0.64
           295                          0.49                       0.31
           285                           0.0                        0.0
           275                          -0.38                     -0.22
           255                          -0.66                     -0.55
           235                          -0.73                     -0.86
           225                          -0.61                     -0.71
           205                          -0.19                     -0.86
            0                            0.0                        0.0

                  Table 1.4.3-4. Corrected values for NOAA-7 Nsp.
                 Channel                              Nsp (mW/(m2-sr-cm-1))
                    3                                          0.0
                    4                                        -1.176
                    5                                        -1.346




                                            1-29         NOAA POD GUIDE - 11/98 Revision
Table 1.4.3-5. PRT Coefficients for all Instruments on NOAA-7 (from NESS 107)
                                      AVHRR
                      PRT counts to Temperature Coefficients
PRT             a0              a1                 a2              a3             a4
  1           277.099       5.048E-02         2.823E-06           0.0            0.0
  2           276.734       5.069E-02         2.496E-06           0.0            0.0
  3           276.876       5.148E-02         1.040E-06           0.0            0.0
  4           276.160       5.128E-02         1.141E-06           0.0            0.0
                             PRT Weighting Factors
       b1                    b2                     b3                      b4
      0.25                  0.25                   0.25                    0.25
            Radiance of Space (Nsp) Including Nonlinearity Correction
               Channel                                Nsp(mW/sr-m2-cm-1)
                   3                                          0.0
                   4                                        -1.176
                   5                                        -1.346
                                       HIRS
                  IWT PRT Count to Temperature Coefficients
 PRT               a0            a1             a2            a3                a4
    1           301.44      6.6679E-03 1.4998E-07 5.5231E-11                    0.0
    2           301.91      7.2367E-03 4.2741E-07 9.0509E-11                    0.0
    3           301.88      7.1208E-03 3.7177E-07 8.2989E-11                    0.0
    4           301.41      6.4985E-03 6.3052E-08 4.1470E-11                    0.0
                                        SSU
                      PRT Count to Temperature Coefficients
           a0                            a1                            a2
        283.9218                    4.85751E-03                        0.0
                      Thermistor to Temperature Coefficients
       b0                    b1                     b2                      b3
    375.969               -203.161               179.13                  -85.16
       c0                    c1                     c2                      c3
    375.969               -203.161               179.13                  -85.16
                                       MSU
                   PRT Resistance to Temperature Coefficients
                  K0                                         495.6
                  K1                                         107.8
                   PRT Resistance to Temperature coefficients
                             e0                     e1                      e2
       1A                  28.976                .42694               .31737E-04
       2A                  28.995                .42627               .31775E-04
       1B                  28.945                .42628               .31603E-04
       2B                  28.964                .42498               .31389E-04
                             Radiance of Space (Nsp)
                                            1-30          NOAA POD GUIDE - 11/98 Revision
        Channel                          Nsp(mW/sr-m2-cm-1)
           1                                  0.000086
           2                                  0.000096
           3                                  0.000084
           4                                  0.000092




Figure 1.4.3-1. Spectral Response Curve NOAA-7 AVHRR Channel 1.




                                 1-31        NOAA POD GUIDE - 11/98 Revision
Figure 1.4.3-2. Spectral Response Curve NOAA-7 AVHRR Channel 2.




                                 1-32        NOAA POD GUIDE - 11/98 Revision
Figure 1.4.3-3. Spectral Response Curve NOAA-7 AVHRR Channel 3.




                                 1-33        NOAA POD GUIDE - 11/98 Revision
Figure 1.4.3-4. Spectral Response Curve NOAA-7 AVHRR Channel 4




                                 1-34       NOAA POD GUIDE - 11/98 Revision
Figure 1.4.3-5. Spectral Response Curve NOAA-7 AVHRR Channel 5.




                                 1-35        NOAA POD GUIDE - 11/98 Revision
1.4.4            NOAA-8

Operational dates:   May 3, 1983 - June 21, 1984
                     July 1, 1985 - October 31, 1985

Morning orbit:       1930 LST ascending node, 0730 LST descending node

AVHRR instrument: 4 channels

Spacecraft ID:       6

Abnormalities:       Primary oscillator began to operate sporadically on June 12, 1984.
                     Between June 12 and 21, 1984, a small amount of GAC, LAC, and TOVS
                     data were recorded. At this point NOAA-8 was turned off. It was not
                     until July 1, 1985 that NOAA-8 was reactivated and all instruments
                     checked out except the HIRS/2 instrument. Due to detector heating while
                     the spacecraft tumbled, channels 1-12 of the HIRS/2 were lost.

Table 1.4.4-1 contains the central wave numbers for the AVHRR IR channels for NOAA-8.
Table 1.4.4-2 contains the TOVS channel spectral response and HIRS/2 thermal band-correction
coefficients for NOAA-8. Non-linearity errors for NOAA-8 AVHRR Channel 4 are contained in
Table 1.4.4-3. Table 1.4.4-4 contains values of the corrected radiance of space, Nsp (which
includes the non-linearity correction) for the NOAA-8 AVHRR IR channels.

Figures 1.4.4-1 through 1.4.4-4 contain the spectral response curves for NOAA-8 channels 1
through 4, respectively.

       Table 1.4.4-1. NOAA-8 Central Wave Numbers for AVHRR IR Channels.
   Temperature Range (K)         Channel 3 (cm-1)         Channel 4 (cm-1)
         180-225                     2631.52                  913.360
         225-275                     2636.05                  913.865
         275-320                     2639.18                  914.305

  Table 1.4.4-2. NOAA-8 TOVS Channel Spectral Response and HIRS/2 Thermal Band-
                              Correction Coefficients.
                                                                 HIRS/2 Band-
                                                                   Correction
                                                                  Coefficients
 Instrument Channel #      Central Wave #       Description      b            c
 HIRS/2        1         667.41 cm-1          15 micrometers 0.099       0.99971
               2         679.45 cm-1          CO2 Band       0.147       0.99962
               3         690.90 cm-1          CO2 Band       0.143       0.99964
               4         702.97 cm-1          CO2 Band       0.010       0.99991
               5         717.56 cm-1          CO2 Band       -0.001      0.99994
               6         732.97 cm-1          CO2 Band       0.193       0.99955
                                                 1-36          NOAA POD GUIDE - 11/98 Revision
           7             747.90 cm-1          CO2 Band          -0.104     1.00013
           8             901.08 cm-1          Window            0.429      0.99931
           9             1027.11 cm-1         Ozone             0.140      0.99984
           10            1224.05 cm-1         Water Vapor       0.450      0.99988
           11            1366.17 cm-1         Water Vapor       0.108      0.99978
           12            1486.92 cm-1         Water Vapor       0.530      1.00008
           13            2189.28 cm-1         4.3 micrometers   0.051      1.00022
           14            2211.71 cm-1         CO2 Band          0.063      1.00029
           15            2238.06 cm-1         CO2 Band          0.015      0.99992
           16            2271.43 cm-1         CO2 Band          0.029      1.00004
           17            2357.11 cm-1         CO2 Band          0.018      0.99993
           18            2515.53 cm-1         Window            0.080      1.00007
           19            2661.85 cm-1         Window            0.489      1.00061
           20            14355.00 cm-1        Visible           n/a        n/a
                                              Window
MSU        1             1.6779 cm-1
           2             1.7927 cm-1
           3             1.8334 cm-1
           4             1.9331 cm-1
SSU        1             669.988 cm-1/15 mb
           2             669.628 cm-1/5 mb
           3             669.357 cm-1/1.5
                         mb

           Table 1.4.4-3. Non-linearity errors for NOAA-8 Channel 4.
       Target temperature (K)                            Error (K)
                 315                                        0.8
                 305                                        0.3
                 295                                       -0.1
                 285                                       -0.3
                 275                                       -0.4
                 255                                       -0.4
                 235                                        0.2
                 225                                        0.7
                 205                                        2.2
                  0                                         0.0

                 Table 1.4.4-4. Corrected values for NOAA-8 Nsp.
                Channel                              Nsp (mW/(m2-sr-cm-1))
                   3                                          0.0
                   4                                        -2.784

  Table 1.4.4-5. PRT Coefficients for all Instruments on NOAA-8 (from NESS 107)
                                           1-37         NOAA POD GUIDE - 11/98 Revision
                                    AVHRR
                     PRT counts to Temperature Coefficients
PRT            a0              a1                 a2              a3             a4
 1           276.585        0.05136          -9.99E-08           0.0            0.0
 2           276.605        0.05122           6.85E-08           0.0            0.0
 3           276.591        0.05133         -1.381E-07           0.0            0.0
 4           276.592        0.05133         -1.489E-07           0.0            0.0
                            PRT Weighting Factors
      b1                    b2                     b3                      b4
     0.25                  0.25                   0.25                    0.25
           Radiance of Space (Nsp) Including Nonlinearity Correction
              Channel                                Nsp(mW/sr-m2-cm-1)
                  3                                          0.0
                  4                                        -2.784
                  5                                        -2.784
                                     HIRS
                 IWT PRT Count to Temperature Coefficients
 PRT              a0            a1             a2            a3                a4
   1           301.77      7.1073E-03 3.9559E-07 9.4570E-11                    0.0
   2           302.23      7.7872E-03 7.1948E-07 1.3802E-10                    0.0
   3           302.27      7.7709E-03 7.0700E-07 1.3688E-10                    0.0
   4           301.71      6.9976E-03 3.3206E-07 8.6808E-11                    0.0
                                      SSU
                     PRT Count to Temperature Coefficients
          a0                           a1                              a2
       285.2978                    4.817E-03                     1.119E-08
                     Thermistor to Temperature Coefficients
      b0                    b1                     b2                      b3
   375.969               -203.161                179.13                 -85.16
      c0                    c1                     c2                      c3
   375.969               -203.161                179.13                 -85.16
                                     MSU
                  PRT Resistance to Temperature Coefficients
                 K0                                         495.6
                 K1                                         107.8
                  PRT Resistance to Temperature coefficients
                            e0                     e1                      e2
      1A                 29.4857               .4247172              .320960E-04
      2A                 29.3123               .4326844            .3282283E-04
      1B                 29.3471               .4247339            .3165123E-04
      2B                 29.9719               .4285466            .3095837E-04
                            Radiance of Space (Nsp)
              Channel                                Nsp(mW/sr-m2-cm-1)
                  1                                       0.000086
                                            1-38          NOAA POD GUIDE - 11/98 Revision
           2                                  0.000096
           3                                  0.000084
           4                                  0.000092




Figure 1.4.4-1. Spectral Response Curve NOAA-8 AVHRR Channel-1




                                1-39        NOAA POD GUIDE - 11/98 Revision
Figure 1.4.4-2. Spectral Response Curve NOAA-8 AVHRR Channel-2.




                                 1-40        NOAA POD GUIDE - 11/98 Revision
Figure 1.4.4-3. Spectral Response Curve NOAA-8 AVHRR Channel-3




                                1-41        NOAA POD GUIDE - 11/98 Revision
Figure 1.4.4-4. Spectral Response Curve NOAA-8 AVHRR Channel-4.




                                 1-42        NOAA POD GUIDE - 11/98 Revision
1.4.5            NOAA-9

Operational dates:    February 25, 1985 - November 7, 1988

Afternoon orbit:      1420 LST ascending node, 0220 LST descending node

AVHRR instrument: 5 channels

Spacecraft ID:        7

Table 1.4.5-1 contains the central wave numbers for the AVHRR IR channels for NOAA-9.
Table 1.4.5-2 contains the TOVS channel spectral response and HIRS/2 thermal band-correction
coefficients for NOAA-9. Non-linearity errors for NOAA-9 AVHRR Channels 4 and 5 are
contained in Table 1.4.5-3. Table 1.4.5-4 contains values of the corrected radiance of space, Nsp
(which includes the non-linearity correction) for the NOAA-9 AVHRR IR channels.

Figures 1.4.5-1 through 1.4.5-5 contain the spectral response curves for NOAA-9 AVHRR
channels 1 through 5, respectively.

      Table 1.4.5-1. NOAA-9 Central Wave Numbers for AVHRR IR Channels.
 Temperature Range (K)   Channel 3 (cm-1)  Channel 4 (cm-1)  Channel 5 (cm-1)
       180-225               2670.93            928.50           844.41
       225-275               2674.81            929.02           844.80
       275-320               2678.11            929.46           845.19

  Table 1.4.5-2. NOAA-9 TOVS Channel Spectral Response and HIRS/2 Thermal Band-
                             Correction Coefficients.
                                                                HIRS/2 Band-
                                                                  Correction
                                                                  Coefficients
 Instrument Channel #     Central Wave #       Description       b            c
   HIRS/2          1        667.67 cm-1      15 micrometers   0.034       0.99989
                   2        679.84 cm-1         CO2 Band      0.024       0.99991
                   3        691.46 cm-1         CO2 Band      0.092       0.99975
                   4        703.37 cm-1         CO2 Band      0.002       0.99993
                   5        717.16 cm-1         CO2 Band      0.013       0.99991
                   6        732.64 cm-1         CO2 Band      -0.023      0.99997
                   7        749.48 cm-1         CO2 Band      -0.006      0.99995
                   8        898.53 cm-1          Window       0.126       0.99969
                   9       1031.61 cm-1           Ozone       0.187       0.99987
                  10       1224.74 cm-1        Water Vapor    0.569       1.00010
                  11       1365.12 cm-1        Water Vapor    0.033       0.99961
                  12       1483.24 cm-1        Water Vapor    0.353       0.99911
                  13       2189.97 cm-1      4.3 micrometers  -0.001      0.99980
                                                   1-43          NOAA POD GUIDE - 11/98 Revision
                14          2209.18 cm-1            CO2 Band       0.007      0.99984
                15          2243.14 cm-1            CO2 Band       0.027      1.00003
                16          2276.46 cm-1            CO2 Band       0.099      1.00038
                17          2359.05 cm-1            CO2 Band       0.004      0.99977
                18          2518.14 cm-1             Window        0.084      1.00012
                19          2667.80 cm-1             Window        0.448      1.00040
                20         14549.27 cm-1             Visible        n/a          n/a
                                                     Window
  MSU            1          1.6779 cm-1
                 2          1.7927 cm-1
                 3          1.8334 cm-1
                 4          1.9331 cm-1
  SSU            1        669.988 cm-1/15
                                 mb
                 2       669.628 cm-1/5 mb
                 3        669.357 cm-1/1.5
                                 mb

          Table 1.4.5-3. Non-linearity errors for NOAA-9 Channels 4 and 5.
 Target temperature (K)          Channel 4 Error (K)        Channel 5 Error (K)
           315                            1.8                        1.0
           305                            0.9                        0.6
           295                            0.2                        0.2
           285                            -0.4                       -0.1
           275                            -0.9                       -0.5
           255                            -1.4                       -0.8
           245                            -1.6                       -1.0
           225                            -1.5                       -1.3
           205                            -1.0                       -1.4

                 Table 1.4.5-4. Corrected values for NOAA-9 Nsp.
                Channel                              Nsp (mW/(m2-sr-cm-1))
                   3                                          0.0
                   4                                        -3.384
                   5                                        -2.313


Table 1.4.5-5. PRT Coefficients for all Instruments on NOAA-9 (from NESS 107)
                                     AVHRR
                    PRT counts to Temperature Coefficients
PRT             a0              a1               a2            a3        a4
  1          277.018        0.05128              0.0           0.0      0.0
  2          276.750        0.05128              0.0           0.0      0.0

                                             1-44         NOAA POD GUIDE - 11/98 Revision
3          276.682       0.05128              0.0              0.0          0.0
4          276.546       0.05128              0.0              0.0          0.0
                         PRT Weighting Factors
    b1                   b2                     b3                     b4
   0.25                 0.25                  0.25                    0.25
        Radiance of Space (Nsp) Including Nonlinearity Correction
           Channel                                Nsp(mW/sr-m2-cm-1)
                3                                          0.0
                4                                        -3.384
                5                                        -2.313
                                  HIRS
               IWT PRT Count to Temperature Coefficients
PRT            a0            a1            a2              a3              a4
 1           301.38     6.5225E-03     8.282E-08      4.8144E-11           0.0
 2           301.37     6.5193E-03 8.5968E-08 4.8101E-11                   0.0
 3           301.38     6.5245E-03 8.6193E-08 4.8146E-11                   0.0
 4           301.37     6.5196E-03 8.5893E-08 4.8105E-11                   0.0
                                   SSU
                  PRT Count to Temperature Coefficients
        a0                          a1                             a2
     284.249                    4.889E-03                       2.6E-09
                  Thermistor to Temperature Coefficients
    b0                   b1                     b2                     b3
 375.969              -203.161               179.13                  -85.16
    c0                   c1                     c2                     c3
 375.969              -203.161               179.13                  -85.16
                                   MSU
                PRT Resistance to Temperature Coefficients
               K0                                         495.6
               K1                                         107.8
                PRT Resistance to Temperature coefficients
                         e0                     e1                     e2
    1A                29.4294              .4283514              .3223351E-04
    2A                29.2639              .4338180              .3334592E-04
    1B                29.5416              .4248521              .3188159E-04
    2B                29.5778              .4243732              .3264424E-04
                         Radiance of Space (Nsp)
           Channel                                Nsp(mW/sr-m2-cm-1)
                1                                      0.000086
                2                                      0.000096
                3                                      0.000084
                4                                      0.000092


                                             1-45         NOAA POD GUIDE - 11/98 Revision
Figure 1.4.5-1. Spectral Response Curve NOAA-9 AVHRR Channel-1.




                                 1-46        NOAA POD GUIDE - 11/98 Revision
Figure 1.4.5-2. Spectral Response Curve NOAA-9 AVHRR Channel-2.




                                 1-47        NOAA POD GUIDE - 11/98 Revision
Figure 1.4.5-3. Spectral Response Curve NOAA-9 AVHRR Channel-3.




                                 1-48        NOAA POD GUIDE - 11/98 Revision
Figure 1.4.5-4. Spectral Response Curve NOAA-9 AVHRR Channel-4




                                1-49        NOAA POD GUIDE - 11/98 Revision
1.4.6            NOAA-10

Operational dates:   Nov. 17, 1986 to Sept. 16, 1991

Morning orbit:       1930 LST ascending node, 0730 LST descending node

AVHRR instrument: 4 channels

Spacecraft ID:       8

Abnormalities:       Last ERBE instrument; no SSU and SBUV instruments flown. HIRS/2
                     instrument had a problem with filter wheel which was corrected with a
                     software patch. The TOVS data became operational Dec. 16, 1986. The
                     AVHRR has a northern latitude ascending spacelook apparent sunlight
                     intrusion that affects the channel 3 space look and calibration for brief
                     periods.

Table 1.4.6-1 contains the central wave numbers for the AVHRR IR channels for NOAA-10.
Table 1.4.6-2 contains the TOVS channel spectral response and HIRS/2 thermal band-correction
coefficients for NOAA-10. Non-linearity corrections for NOAA-10 AVHRR Channel 4 are
contained in Table 1.4.6-3. The non-linearity corrections are the difference between the
measured target temperature and that temperature derived from a two-point linear calibration
using a radiance of space of zero. Table 1.4.6-4 contains values of the corrected radiance of
space, Nsp (which includes the non-linearity correction) for NOAA-10 AVHRR Channel 4.

Figures 1.4.6-1 through 1.4.6-4 contain the spectral response curves for NOAA-10 AVHRR
channels 1 through 4.

        Table 1.4.6-1. NOAA-10 Central Wave Numbers for AVHRR IR Channels.
 Temperature Range (K)          Channel 3 (cm-1)                Channel 4 (cm-1)
 180-225                        2658.53                         908.73
 225-275                        2657.60                         909.18
 275-320                        2660.76                         909.58
 270-310                        2660.35                         909.52
 Note: The 270-310 K range is applicable for sea surface temperatures.

 Table 1.4.6-2. NOAA-10 TOVS Channel Spectral Response and HIRS/2 Thermal Band-
                              Correction Coefficients.
                                                                 HIRS/2 Band-
                                                                   Correction
                                                                  Coefficients
 Instrument Channel #      Central Wave #       Description      b            c
 HIRS/2        1         667.70 cm-1          15 micrometers 0.033       0.99989
               2         680.23 cm-1          CO2 Band       0.018       0.99992
               3         691.15 cm-1          CO2 Band       -0.006      0.99994
                                                 1-50          NOAA POD GUIDE - 11/98 Revision
            4             704.33 cm-1         CO2 Band          -0.002     0.99994
            5             716.30 cm-1         CO2 Band          -0.064     1.00007
            6             733.13 cm-1         CO2 Band          0.065      0.99980
            7             750.72 cm-1         CO2 Band          0.073      0.99979
            8             899.50 cm-1         Window            0.218      0.99957
            9             1029.01 cm-1        Ozone             0.195      0.99987
            10            1224.07 cm-1        Water Vapor       0.327      0.99965
            11            1363.32 cm-1        Water Vapor       0.046      0.99963
            12            1489.42 cm-1        Water Vapor       0.645      1.00064
            13            2191.38 cm-1        4.3 micrometers   0.072      1.00036
            14            2208.74 cm-1        CO2 Band          0.079      1.00045
            15            2237.49 cm-1        CO2 Band          -0.026     0.99947
            16            2269.09 cm-1        CO2 Band          0.041      1.00019
            17            2360.00 cm-1        CO2 Band          0.040      1.00019
            18            2514.58 cm-1        Window            0.098      1.00025
            19            2665.38 cm-1        Window            0.462      1.00067
            20            14453.14 cm-1       Visible           n/a        n/a
                                              Window
MSU         1            1.6779 cm-1
            2            1.7927 cm-1
            3            1.8334 cm-1
            4            1.9331 cm-1
SSU         Instrument not flown on NOAA-10

             Table 1.4.6-3. Non-linearity errors for NOAA-10 Channel 4.
                                     Internal Target Temperature (Degrees C)
 Target temperature (K)              10                 15                 20
           320                      3.50               2.83               2.54
           315                      2.93               2.19               1.97
           305                      1.88               1.34               1.11
           295                      1.12               0.57               0.12
           285                      0.20               -0.15             -0.38
           275                     -0.46               -0.53             -1.08
           265                     -0.76               -0.93             -1.37
           255                     -1.33               -1.49             -1.77
           245                     -1.74               -2.09             -2.26
           235                     -1.79               -2.20             -2.53
           225                     -2.22               -2.51             -2.53
           215                     -2.58               -2.65             -2.80
           205                     -2.47               -2.88             -3.27

                  Table 1.4.6-4. Corrected values for NOAA-10 Nsp.
                 Channel                              Nsp (mW/(m2-sr-cm-1))
                                            1-51        NOAA POD GUIDE - 11/98 Revision
                     3                                            0.0
                     4                                            0.0

Table 1.4.6-5. PRT Coefficients for all Instruments on NOAA-10 (from NESS 107)
                                      AVHRR
                       PRT counts to Temperature Coefficients
 PRT             a0              a1                 a2              a3           a4
  1           276.659         0.051275         1.363E-06            0.0         0.0
  2        278.2352898        0.051275           1.363E             0.0         0.0
  3        278.0691316        0.051275           1.363E             0.0         0.0
  4        277.9288372        0.051275           1.363E             0.0         0.0
                              PRT Weighting Factors
       b1                     b2                     b3                    b4
      0.25                   0.25                   0.25                  0.25
            Radiance of Space (Nsp) Including Nonlinearity Correction
                Channel                                Nsp(mW/sr-m2-cm-1)
                    3                                          0.0
                    4                                          0..0
                    5                                          0.0
                                       HIRS
                   IWT PRT Count to Temperature Coefficients
  PRT               a0            a1             a2             a3             a4
    1            301.38      6.5216E-03 8.6344E-08 4.8114E-11                  0.0
    2            301.38      6.5161E-03 8.5966E-08 4.8042E-11                  0.0
    3            301.38      6.5207E-03 8.65966E-08 4.8083E-11                 0.0
    4            301.38      6.5197E-03 8.6161E-08 4.8073E-11                  0.0
                         SSU-NOAA 10 Has a Dummy SSU
                                        MSU
                    PRT Resistance to Temperature Coefficients
                   K0                                         495.6
                   K1                                         107.8
                     PRT Resistance to Temperature coefficients
                              e0                     e1                    e2
       1A                  29.2589               .4245799             .3169871E-04
       2A                  29.4633               .4250778             .3192864E-04
       1B                  29.2350               .4289328             .3232162E-04
       2B                  29.4680               .4275379             .3221571E-04
                              Radiance of Space (Nsp)
                Channel                                Nsp(mW/sr-m2-cm-1)
                    1                                       0.000086
                    2                                       0.000096
                    3                                       0.000084
                    4                                       0.000092

                                               1-52         NOAA POD GUIDE - 11/98 Revision
Figure 1.4.6-1. Spectral Response Curve NOAA-10 AVHRR Channel-1.




                                  1-53       NOAA POD GUIDE - 11/98 Revision
Figure 1.4.6-2. Spectral Response Curve NOAA-10 AVHRR Channel-2.




                                  1-54       NOAA POD GUIDE - 11/98 Revision
Figure 1.4.6-3. Spectral Response Curve NOAA-10 AVHRR Channel-3.




                                  1-55       NOAA POD GUIDE - 11/98 Revision
Figure 1.4.6-4. Spectral Response Curve NOAA-10 AVHRR Channel-4.




                                  1-56       NOAA POD GUIDE - 11/98 Revision
1.4.7            NOAA-11

Operational dates:    November 8, 1988 to April 11, 1995

Afternoon orbit:      1340 LST ascending node, 0140 LST descending node

AVHRR instrument: 5 channels

Spacecraft ID:        1 (same as TIROS-N)

Abnormalities:        AVHRR instrument failed on Sept. 13, 1994.

Table 1.4.7-1 contains the central wave numbers for the AVHRR IR channels for NOAA-11.
Table 1.4.7-2 contains the TOVS channel spectral response and HIRS/2 thermal band-correction
coefficients for NOAA-11. Non-linearity corrections for NOAA-11 AVHRR Channel 4 and 5
are contained in Tables 1.4.7-3 and 1.4.7-4, respectively. The non-linearity corrections are the
difference between the measured target temperature and that temperature derived from a two-
point linear calibration using a radiance of space (Nsp) of zero. The non-linearity correction can
be obtained from Tables 1.4.7-3 and 1.4.7-4 by interpolation on the scene temperatures and the
temperatures of the AVHRR's internal calibration target.

Figures 1.4.7-1 through 1.4.7-5 contain the spectral response curves for NOAA-11 AVHRR
channels 1 through 5, respectively.

        Table 1.4.7-1. NOAA-11 Central Wave Numbers for AVHRR IR Channels.
  Temperature Range (K)         Channel 3 (cm-1) Channel 4 (cm-1) Channel 5 (cm-1)
           180-225                   2663.50                926.81     841.40
           225-275                   2668.15                927.36     841.81
           275-320                   2671.40                927.83     842.20
           270-310                   2670.96                927.75     842.14
 Note: The 270-310 K range is applicable for sea surface temperatures.

 Table 1.4.7-2. NOAA-11 TOVS Channel Spectral Response and HIRS/2 Thermal Band-
                              Correction Coefficients.
                                                                 HIRS/2 Band-
                                                                   Correction
                                                                  Coefficients
 Instrument Channel #      Central Wave #       Description      b            c
 HIRS/2        1         668.99 cm-1          15 micrometers 0.007       0.99996
               2         678.89 cm-1          CO2 Band       0.010       0.99994
               3         689.70 cm-1          CO2 Band       0.007       0.99992
               4         703.25 cm-1          CO2 Band       -0.003      0.99995
               5         716.83 cm-1          CO2 Band       0.014       0.99991
               6         732.11 cm-1          CO2 Band       0.019       0.99991
                                                   1-57           NOAA POD GUIDE - 11/98 Revision
            7            749.48 cm-1          CO2 Band          0.032      0.99988
            8            900.51 cm-1          Window            0.077      0.99988
            9            1031.19 cm-1         Ozone             0.068      0.99975
            10           795.69 cm-1          Water Vapor       -0.001     0.99994
            11           1361.10 cm-1         Water Vapor       0.074      0.99972
            12           1479.86 cm-1         Water Vapor       0.288      0.99994
            13           2189.94 cm-1         4.3 micrometers   0.022      0.99994
            14           2209.66 cm-1         CO2 Band          0.018      0.99995
            15           2239.26 cm-1         CO2 Band          0.020      0.99995
            16           2267.80 cm-1         CO2 Band          0.015      0.99993
            17           2416.32 cm-1         CO2 Band          0.024      0.99991
            18           2511.83 cm-1         Window            0.045      0.99990
            19           2664.07 cm-1         Window            0.325      0.99949
            20           14453.14 cm-1        Visible           n/a        n/a
                                              Window
MSU         1            1.6779 cm-1
            2            1.7927 cm-1
            3            1.8334 cm-1
            4            1.9331 cm-1
SSU         1            669.988 cm-1/15 mb
            2            669.628 cm-1/5 mb
            3            669.357 cm-1/1.5
                         mb

             Table 1.4.7-3. Non-linearity errors for NOAA-11 Channel 4.
                                     Internal Target Temperature (Degrees C)
 Target temperature (K)              10                 15                 20
           320                      4.29               3.71               3.25
           315                      3.50               2.98               2.55
           310                      2.85               2.33               1.91
           305                      2.23               1.73               1.32
           295                      1.05               0.68               0.22
           285                      0.24               -0.21             -0.67
           275                     -0.45               -0.79             -1.15
           265                     -1.06               -1.37             -1.66
           255                     -1.41               -1.72             -2.03
           245                     -1.70               -1.96             -2.22
           235                     -1.87               -2.10             -2.28
           225                     -1.90               -2.14             -2.36
           215                     -1.82               -2.02             -2.20
           205                     -1.54               -1.76             -1.98



                                           1-58         NOAA POD GUIDE - 11/98 Revision
              Table 1.4.7-4. Non-linearity errors for NOAA-11 Channel 5.
                                      Internal Target Temperature (Degrees C)
  Target temperature (K)              10                 15                 20
            320                      1.43               1.28               1.12
            315                      1.23               1.03               0.89
            310                      1.05               0.84               0.70
            305                      0.85               0.64               0.47
            295                      0.43               0.28               0.09
            285                      0.07               -0.07             -0.23
            275                     -0.19               -0.34             -0.47
            265                     -0.37               -0.51             -0.60
            255                     -0.60               -0.77             -0.78
            245                     -0.72               -0.90             -0.92
            235                     -0.84               -1.02             -1.00
            225                     -0.94               -1.06             -1.16
            215                     -1.12               -1.24             -1.16
            205                     -1.15               -1.27             -1.23

Table 1.4.7-5. PRT Coefficients for all Instruments on NOAA-11 (from NESS 107)
                                      AVHRR
                       PRT counts to Temperature Coefficients
 PRT             a0              a1                a2             a3           a4
  1           276.597         0.051275             0.0            0.0          0.0
  2           276.597         0.051275             0.0            0.0          0.0
  3           276.597         0.051275             0.0            0.0          0.0
  4           276.597         0.051275             0.0            0.0          0.0
                              PRT Weighting Factors
       b1                     b2                     b3                   b4
      0.25                   0.25                  0.25                  0.25
            Radiance of Space (Nsp) Including Nonlinearity Correction
                Channel                                Nsp(mW/sr-m2-cm-1)
                    3                                         0.0
                    4                                         0.0
                    5                                         0.0
                                       HIRS
                   IWT PRT Count to Temperature Coefficients
  PRT               a0            a1            a2            a3              a4
    1          301.37210 6.52057E-03 9.05197E-08 4.73741E-11 8.29062E-16
    2          301.37560 6.52283E-03 9.13565E-08 4.73871E-11 7.86019E-16
    3          301.41250 6.51819E-03 9.18444E-08 4.75139E-11 7.30508E-16
    4          301.37420 6.51875E-03 9.04524E-08 4.72894E-11 8.06020E-16
                                        SSU
                       PRT Count to Temperature Coefficients
           a0                            a1                           a2
                                              1-59         NOAA POD GUIDE - 11/98 Revision
   283.901                   5.044E-03                    1.18E-11
               Thermistor to Temperature Coefficients
  b0                  b1                   b2                    b3
375.969            -203.161              179.13                -85.16
  c0                  c1                   c2                    c3
375.969            -203.161              179.13                -85.16
                               MSU
            PRT Resistance to Temperature Coefficients
            K0                                      495.6
            K1                                      107.8
             PRT Resistance to Temperature coefficients
                      e0                   e1                    e2
  1A               29.1014             .4242637            .3162073E-04
  2A               28.9481             .4277704            .3185110E-04
  1B               28.9854             .4269018            .3170732E-04
  2B               29.0424             .4274570            .3191209E-04
                      Radiance of Space (Nsp)
          Channel                            Nsp(mW/sr-m2-cm-1)
             1                                    0.000086
             2                                    0.000096
             3                                    0.000084
             4                                    0.000092




                                       1-60         NOAA POD GUIDE - 11/98 Revision
Figure 1.4.7-1. Spectral Response Curve NOAA-11 AVHRR Channel-1




                                 1-61        NOAA POD GUIDE - 11/98 Revision
Figure 1.4.7-2. Spectral Response Curve NOAA-11 AVHRR Channel-2




                                 1-62        NOAA POD GUIDE - 11/98 Revision
Figure 1.4.7-3. Spectral Response Curve NOAA-11 AVHRR Channel-3.




                                  1-63       NOAA POD GUIDE - 11/98 Revision
Figure 1.4.7-4. Spectral Response Curve NOAA-11 AVHRR Channel-4.




                                  1-64       NOAA POD GUIDE - 11/98 Revision
Figure 1.4.7-5. Spectral Response Curve NOAA-11 AVHRR Channel-5




                                 1-65        NOAA POD GUIDE - 11/98 Revision
1.4.8            NOAA-12

Operational dates:    September 16, 1991 to present

Morning orbit:        1930 LST ascending node, 0730 descending node

AVHRR instrument: 5 channels

Spacecraft ID:        5

Table 1.4.8-1 contains the central wave numbers for the AVHRR IR channels for NOAA-12.
Table 1.4.8-2 contains the TOVS channel spectral response and HIRS/2 thermal band-correction
coefficients for NOAA-12. Non-linearity corrections for NOAA-12 AVHRR Channels 4 and 5
are contained in Tables 1.4.8-3 and 1.4.8-4. The non-linearity corrections are the difference
between the measured target temperature and that temperature derived from a two-point linear
calibration using a radiance of space (Nsp) of zero. The non-linearity correction can be obtained
from Tables 1.4.8-3 and 1.4.8-4 by interpolation on the scene temperatures and the temperatures
of the AVHRR's internal calibration target.

Figures 1.4.8-1 through 1.4.8-5 contain the spectral response curves for NOAA-12 AVHRR
channels 1 through 5, respectively.

        Table 1.4.8-1. NOAA-12 Central Wave Numbers for AVHRR IR Channels.
  Temperature Range (K)         Channel 3 (cm-1) Channel 4 (cm-1) Channel 5 (cm-1)
           190-230                   2632.713              920.0158    836.6847
           230-270                   2636.669              920.5504    837.0251
           270-310                    2639.61              921.0291    837.3641
           290-330                   2640.817              921.2741    837.5612
 Note: The 270-310 K range is applicable for sea surface temperatures.

 Table 1.4.8-2. NOAA-12 TOVS Channel Spectral Response and HIRS/2 Thermal Band-
                              Correction Coefficients.
                                                                 HIRS/2 Band-
                                                                   Correction
                                                                  Coefficients
 Instrument Channel #      Central Wave #       Description      b            c
 HIRS/2        1         667.58 cm-1          15 micrometers 0.007       0.99996
               2         680.18 cm-1          CO2 Band       0.007       0.99995
               3         690.01 cm-1          CO2 Band       0.019       0.99989
               4         704.22 cm-1          CO2 Band       0.026       0.99988
               5         716.32 cm-1          CO2 Band       0.021       0.99990
               6         732.81 cm-1          CO2 Band       0.140       0.99964
               7         751.92 cm-1          CO2 Band       0.058       0.99982
               8         900.45 cm-1          Window         0.358       0.99940

                                                   1-66          NOAA POD GUIDE - 11/98 Revision
             9            1026.66 cm-1         Ozone             0.181      0.99985
             10           1223.44 cm-1         Water Vapor       0.377      0.99975
             11           1368.68 cm-1         Water Vapor       0.175      0.99992
             12           1478.59 cm-1         Water Vapor       0.265      0.99863
             13           2190.37 cm-1         4.3 micrometers   0.078      1.00042
             14           2210.51 cm-1         CO2 Band          0.017      0.99995
             15           2236.62 cm-1         CO2 Band          -0.023     0.99950
             16           2267.62 cm-1         CO2 Band          0.021      0.99995
             17           2361.64 cm-1         CO2 Band          0.022      0.99997
             18           2514.68 cm-1         Window            0.058      0.99992
             19           2653.48 cm-1         Window            0.344      0.99950
             20           14453.14 cm-1        Visible           n/a        n/a
                                               Window
MSU          1            1.6799 cm-1
             2            1.7927 cm-1
             3            1.8334 cm-1
             4            1.9331 cm-1
SSU          Instrument not flown on NOAA-12

             Table 1.4.8-3. Non-linearity errors for NOAA-12 Channel 4.
 Target temperature (K)              Internal Target Temperature (Degrees C)
                                 10               15          20               25
           320                  3.21            2.88         2.27            1.91
           315                  2.58            2.39         1.72            1.43
           310                  2.04            1.94         1.28            0.98
           305                   1.6            1.42          0.8            0.52
           295                   0.8            0.53         0.13            -0.16
           285                  0.16            -0.23        -0.52            -0.7
           275                 -0.41            -0.84        -1.05           -1.19
           265                 -.071            -0.97        -1.19           -1.32
           255                 -1.04             -1.2        -1.53           -1.59
           245                 -1.18             -1.4        -1.58           -1.62
           235                 -1.05            -1.59        -1.51           -1.63
           225                 -1.33            -1.65        -1.58           -1.67
           215                 -1.24            -1.65        -1.49           -1.53
           205                 -1.58             -1.8        -1.31           -1.33

            Table 1.4.8-4. Non-linearity errors for NOAA-12 Channel 5.
                                   Internal Target Temperature (Degrees C)
 Target temperature (K)         10              15           20             25
320                        0.8             0.8          0.8            0.73
315                        0.8             0.8          0.73           0.61
310                        0.8             0.73         0.61           0.37
                                             1-67        NOAA POD GUIDE - 11/98 Revision
305                           0.73            0.61            0.37            0.18
295                           0.37            0.18            0.08            -0.08
285                           0.08            -0.08           -0.21           -0.31
275                           -0.21           -0.31           -0.37           -0.41
265                           -0.37           -0.41           -0.47           -0.53
255                           -0.47           -0.53           -0.63           -0.76
245                           -0.63           -0.76           -0.88           -0.94
235                           -0.88           -0.94           -1.01           -1.1
225                           -1.01           -1.1            -1.15           -1.19
215                           -1.15           -1.19           -1.17           -1.16
205                           -1.17           -1.16           -1.19           -1.23

Table 1.4.8-5. PRT Coefficients for all Instruments on NOAA-12 (from NESS 107)
                                     AVHRR
                     PRT counts to Temperature Coefficients
PRT            a0                a1                 a2              a3            a4
 1          276.597           0.051275         1.363E-06            0.0           0.0
 2          276.597           0.051275           1.363E             0.0           0.0
 3          276.597           0.051275           1.363E             0.0           0.0
 4          276.597           0.051275           1.363E             0.0           0.0
                              PRT Weighting Factors
       b1                     b2                     b3                     b4
      0.25                   0.25                   0.25                   0.25
            Radiance of Space (Nsp) Including Nonlinearity Correction
                Channel                                Nsp(mW/sr-m2-cm-1)
                   3                                            0.0
                   4                                            0.0
                   5                                            0.0
                                       HIRS
                  IWT PRT Count to Temperature Coefficients
PRT         a0             a1               a2               a3                a4
 1     301.38300      6.52454E-03      8.63834E-08      4.81705E-11      1.17918E-11
 2     301.38490      6.51937E-03      8.61601E-08      4.81257E-11      1.17221E-15
 3     301.39920      6.51150E-03      8.58417E-08      4.80590E-11      1.17105E-15
 4     301.38770      6.52454E-03      8.63606E-08      4.81834E-11 1.177669E-15
                   SSU – No SSU Instrument aboard NOAA-12
                                        MSU
                   PRT Resistance to Temperature Coefficients
                  K0                                          495.6
                  K1                                          107.8
                   PRT Resistance to Temperature coefficients
                              e0                     e1                     e2
       1A                  29.3970               .4256561             .3238697E-04
       2A                  28.4527               .4293800             .2974601E-04
                                                1-68          NOAA POD GUIDE - 11/98 Revision
1B              28.1854             .4302196           .2920356E-04
2B              28.9588             .4276377           .3033068E-04
                   Radiance of Space (Nsp)
      Channel                             Nsp(mW/sr-m2-cm-1)
         1                                     0.000086
         2                                     0.000096
         3                                     0.000084
         4                                     0.000092




 Figure 1.4.8-1. Spectral Response Curve NOAA-12 AVHRR Channel-1




                                   1-69         NOAA POD GUIDE - 11/98 Revision
Figure 1.4.8-2. Spectral Response Curve NOAA-12 AVHRR Channel-2.




                                  1-70       NOAA POD GUIDE - 11/98 Revision
Figure 1.4.8-3. Spectral Response Curve NOAA-12 AVHRR Channel-3.




                                  1-71       NOAA POD GUIDE - 11/98 Revision
Figure 1.4.8-4. Spectral Response Curve NOAA-12 AVHRR Channel-4.




                                  1-72       NOAA POD GUIDE - 11/98 Revision
Figure 1.4.8-5. Spectral Response Curve NOAA-12 AVHRR Channel-5.




                                  1-73       NOAA POD GUIDE - 11/98 Revision
1.4.9            NOAA-13

Operational dates:    Aug. 9, 1993 - Aug. 21, 1993

Afternoon orbit:      1340 LST ascending node, 0140 descending node

AVHRR instrument: 5 channels

Spacecraft ID:        3

Table 1.4.9-1 contains the central wave numbers for the AVHRR IR channels for NOAA-13.
Table 1.4.9-2 contains the TOVS channel spectral response and HIRS/2 thermal band-correction
coefficients for NOAA-13. Non-linearity corrections for NOAA-13 AVHRR Channels 4 and 5
are contained in Table 1.4.9-3. The non-linearity correction can be obtained from Table 1.4.9-3
by interpolation on the scene temperatures and the temperatures of the AVHRR's internal
calibration target.

With the launch of NOAA-13, NESDIS changed their method of handling the non-linearity
correction. See Section 3.3.1.2 for NESDIS' alternate method for calculating the non-linearity
correction. Use Equation 3.3.1.2-1 to calculate the corrected radiance. Table 1.4.9-4 contains
the coefficients A, B, and C for the quadratic equation in Equation 3.3.1.2-1 and the radiance of
space which are required to calculate the corrected radiance.

Figures 1.4.9-1 through 1.4.9-5 contain the spectral response curves for NOAA-13 AVHRR
channels 1 through 5, respectively.

        Table 1.4.9-1. NOAA-13 Central Wave Numbers for AVHRR IR Channels.
  Temperature Range (K)         Channel 3 (cm-1) Channel 4 (cm-1) Channel 5 (cm-1)
           190-230                   2636.124              924.0114    836.1164
           230-270                   2640.147              924.5165    836.4339
           270-310                   2643.153              924.9732    836.7651
           290-330                   2644.382              925.2164    836.9520
 Note: The 270-310 K range is applicable for sea surface temperatures.

 Table 1.4.9-2. NOAA-13 TOVS Channel Spectral Response and HIRS/2 Thermal Band-
                              Correction Coefficients.
                                                                 HIRS/2 Band-
                                                                   Correction
                                                                  Coefficients
 Instrument Channel #      Central Wave #       Description      b            c
 HIRS/2        1         668.81 cm-1          15 micrometers -0.077      1.00019
               2         679.59 cm-1          CO2 Band       0.020       0.99992
               3         690.18 cm-1          CO2 Band       0.016       0.99993
                                                   1-74           NOAA POD GUIDE - 11/98 Revision
            4           703.02 cm-1          CO2 Band          0.018      0.99991
            5           715.96 cm-1          CO2 Band          0.040      0.99986
            6           732.98 cm-1          CO2 Band          0.028      0.99987
            7           749.34 cm-1          CO2 Band          -0.034     1.00000
            8           902.39 cm-1          Window            0.544      0.99916
            9           1028.77 cm-1         Ozone             0.062      0.99979
            10          792.82 cm-1          Water Vapor       -0.005     0.99994
            11          1359.95 cm-1         Water Vapor       0.090      0.99972
            12          1479.90 cm-1         Water Vapor       0.292      0.99931
            13          2189.06 cm-1         4.3 micrometers   0.022      0.99997
            14          2212.55 cm-1         CO2 Band          0.021      0.99997
            15          2231.68 cm-1         CO2 Band          0.029      0.99993
            16          2267.04 cm-1         CO2 Band          0.022      0.99999
            17          2418.31 cm-1         CO2 Band          0.025      0.99992
            18          2516.80 cm-1         Window            0.058      0.99970
            19          2653.33 cm-1         Window            0.264      0.99927
            20          14453.14 cm-1        Visible           n/a        n/a
                                             Window
MSU         1           1.6779 cm-1
            2           1.7927 cm-1
            3           1.8334 cm-1
            4           1.9331 cm-1
SSU         1           669.988 cm-1/15 mb
            2           669.628 cm-1/5 mb
            3           669.357 cm-1/1.5
                        mb

     Table 1.4.9-3. Non-linearity errors for NOAA-13 AVHRR Channels 4 and 5.
                                              Temperature Corrections
 Scene temperature (K)               Channel 4                     Channel 5
          320                           0.025                         0.20
          315                            0.07                         0.03
          310                           -0.01                         -0.02
          305                           -0.09                         -0.06
          295                           -0.00                         0.01
          285                            0.07                         0.01
          275                            0.24                         0.13
          265                            0.87                         0.40
          255                            1.47                         0.70
          245                            2.14                         1.05
          235                            3.32                         1.43
          225                            4.53                         2.27
          215                            5.93                         3.02
                                          1-75         NOAA POD GUIDE - 11/98 Revision
           205                          9.42                           3.96

 Table 1.4.9-4. Non-linearity coefficients and radiance of space for NOAA-13 AVHRR
                         Channels 4 and 5 (Alternate method).
Radiance Correction Coefficients           Channel 4                  Channel 5
                A                           0.91159                    0.94784
                B                          0.0003820                  0.0002057
                C                              5.01                      3.24
     Radiance of Space, Rsp                   -5.31                      -3.28

Table 1.4.9-5. PRT Coefficients for all Instruments on NOAA-13 (from NESS 107
                                       AVHRR
                       PRT counts to Temperature Coefficients
 PRT             a0               a1                a2            a3          a4
  1           276.597         0.051275         1.363E-06         0.0          0.0
  2           276.597         0.051275           1.363E          0.0          0.0
  3           276.597         0.051275           1.363E          0.0          0.0
  4           276.597         0.051275           1.363E          0.0          0.0
                              PRT Weighting Factors
       b1                     b2                     b3                  b4
      0.25                   0.25                   0.25                0.25
                                        HIRS
                   IWT PRT Count to Temperature Coefficients
  PRT               a0             a1            a2           a3             a4
    1          301.37210 6.52057E-03 9.05197E-08 4.73741E-11 8.29062E-16
    2          301.37560 6.52283E-03 9.13565E-08 4.73871E-11 7.86019E-16
    3          301.41250 6.51819E-03 9.18444E-08 4.75139E-11 7.30508E-16
    4          301.37420 6.51875E-03 9.04524E-08 4.72894E-11 8.06020E-16
                                         SSU
                       PRT Count to Temperature Coefficients
           a0                             a1                         a2
        284.125                       4.819E-03                   8.75E-09
                       Thermistor to Temperature Coefficients
       b0                     b1                     b2                  b3
    375.969                -203.161                179.13              -85.16
       c0                      c1                    c2                  c3
    375.969                -203.161                179.13              -85.16
                                        MSU
                    PRT Resistance to Temperature Coefficients
                   K0                                       495.6
                   K1                                       107.8
                     PRT Resistance to Temperature coefficients
                               e0                    e1                  e2
       1A                  28.74552              .4278088          .3056633E-04
                                               1-76        NOAA POD GUIDE - 11/98 Revision
2A            28.86749            .4263018           .3083285E-04
1B            28.73856            .4335265           .3147607E-04
2B            28.67430            .4282688           .3054580E-04
                 Radiance of Space (Nsp)
      Channel                           Nsp(mW/sr-m2-cm-1)
         1                                   0.000086
         2                                   0.000096
         3                                   0.000084
         4                                   0.000092




 Figure 1.4.9-1. Spectral Response Curve NOAA-13 AVHRR Channel-1




                                   1-77        NOAA POD GUIDE - 11/98 Revision
Figure 1.4.9-2. Spectral Response Curve NOAA-13 AVHRR Channel-2




                                 1-78        NOAA POD GUIDE - 11/98 Revision
Figure 1.4.9-3. Spectral Response Curve NOAA-13 AVHRR Channel-3




                                 1-79        NOAA POD GUIDE - 11/98 Revision
Figure 1.4.9-4. Spectral Response Curve NOAA-13 AVHRR Channel-4




                                 1-80        NOAA POD GUIDE - 11/98 Revision
Figure 1.4.9-5. Spectral Response Curve NOAA-13 AVHRR Channel-5




                                 1-81        NOAA POD GUIDE - 11/98 Revision
1.4.10               NOAA-14

Operational dates:   Dec. 30, 1994 - present

Afternoon orbit:     1340 LST ascending node, 0140 LST descending node

AVHRR instrument: 5 channels

Spacecraft ID:       3

Abnormalities:       The MSU instrument on NOAA-14 failed on March 3, 1995 at 0100 UTC,
                     but was successfully turned back on March 30, 1995.

Table 1.4.10-1 contains the central wave numbers for the AVHRR IR channels for NOAA-14.
Table 1.4.10-2 contains the TOVS channel spectral response and HIRS/2 thermal band-
correction coefficients for NOAA-14.

       Table 1.4.10-1. NOAA-14 Central Wave Numbers for AVHRR IR Channels.
  Temperature Range (K)            Ch. 3 (cm-1)          Ch. 4 (cm-1)  Ch. 5 (cm-1)
           190-230                   2638.652              928.2603     834.4496
           230-270                   2642.807              928.8284     834.8066
           270-310                   2645.899              929.3323     835.1647
           290-330                   2647.169              929.5878      835.374
 Note: The 270-310 K range is applicable for sea surface temperatures.

         Table 1.4.10-2. NOAA-14 TOVS Channel Spectral Response and HIRS/2
                          Thermal Band-Correction Coefficients.
                                                                  HIRS/2 Band-
                                                                   Correction
                                                                   Coefficients
     Instrument Ch #        Central Wave #    Description        b           c
     HIRS/2        1       668.90 cm-1      15 micrometers 0.002       0.99998
                   2       679.36 cm-1      CO2 Band          -0.000   0.99997
                   3       689.63 cm-1      CO2 Band          0.011    0.99994
                   4       703.56 cm-1      CO2 Band          0.001    0.99994
                   5       714.50 cm-1      CO2 Band          -0.014   0.99997
                   6       732.28 cm-1      CO2 Band          0.026    0.99989
                   7       749.64 cm-1      CO2 Band          0.019    0.99991
                   8       898.67 cm-1      Window            0.067    0.99977
                   9       1028.31 cm-1     Ozone             0.050    0.99980
                   10      796.04 cm-1      Water Vapor       0.021    0.99990
                   11      1360.95 cm-1     Water Vapor       0.073    0.99971
                                               1-82         NOAA POD GUIDE - 11/98 Revision
                     12       1481.00 cm-1            Water Vapor       0.284      0.99931
                     13       2191.32 cm-1            4.3 micrometers   0.021      0.99996
                     14       2207.36 cm-1            CO2 Band          0.020      0.99997
                     15       2236.39 cm-1            CO2 Band          0.024      0.99998
                     16       2268.12 cm-1            CO2 Band          0.018      0.99996
                     17       2420.24 cm-1            CO2 Band          0.026      0.99992
                     18       2512.21 cm-1            Window            0.042      0.99993
                     19       2647.91 cm-1            Window            0.313      0.99946
                     20       14453.14 cm-1           Visible           n/a        n/a
                                                      Window
     MSU             1        1.6779 cm-1
                     2        1.7927 cm-1
                     3        1.8334 cm-1
                     4        1.9331 cm-1
     SSU             1        669.988 cm-1/15
                              mb
                     2        669.628 cm-1/5
                              mb
                     3        669.357 cm-1/1.5
                              mb

Beginning with the NOAA-13 AVHRR instrument, a new radiance correction procedure is being
implemented at NESDIS which corrects both the non-linearity of AVHRR Channels 4 and 5 and
the observed offset of the space point from the calibration curve for Channel 3. As was the case
with previous instruments, gain and slope calibration coefficients for each channel are imbedded
in the Level 1b data stream which allows the user to perform a linear calibration. However,
these coefficients are derived using a non-zero radiance of space, Rsp which is a constant for each
channel and which makes the radiance corrections independent of the internal calibration target

                                                  R T - R sp
                                            G=
                                                  CT - Csp


                                           I = R sp - G x Csp

temperature. The slope and intercept coefficients are derived with the following equations:
where G is the slope, I is the intercept, RT is the radiance of the target, CT is the counts of the

                                           R lin = G x C + I

target, and Csp is counts of space. These coefficients provide a linear radiance, Rlin:
where C is the counts of the channel.


                                                       1-83         NOAA POD GUIDE - 11/98 Revision
This linear calibration procedure is described in more detail in NOAA Technical Memorandum
NESS 107. The following equation provides a corrected radiance, RAD, for AVHRR channels 3,
4, and 5 which is a function only of the linear radiance derived from Eq. (3):
This radiance can be converted to temperatures using the energy tables or by using the inverse of
the Planck function with the appropriate central wave numbers. No additional temperature
correction should be applied. The regression coefficients (A, B and D) to apply this equation for
NOAA-14 AVHRR Channels 3, 4 and 5 are contained in Table 1.4.10-3.

         Table 1.4.10-3. Radiance correction coefficients for NOAA-14 AVHRR
                                  Channels 3, 4, and 5.
  Radiance Correction Coefficients     Channel 3           Channel 4     Channel 5
                 A                       1.00359            0.92378       0.96194
                 B                          0.0            0.0003822     0.0001742
                 D                       -0.0031              3.72          2.00
       Radiance of Space, Rsp             0.0069              -4.05         -2.29

 Table 1.4.10-5. PRT Coefficients for all Instruments on NOAA-14 (from NESS 107)
                                        AVHRR
                         PRT counts to Temperature Coefficients
  PRT              a0              a1                a2            a3           a4
    1           276.597         0.051275        1.363E-06          0.0          0.0
    2           276.597         0.051275          1.363E           0.0          0.0
    3           276.597         0.051275          1.363E           0.0          0.0
    4           276.597         0.051275          1.363E           0.0          0.0
                                PRT Weighting Factors
         b1                     b2                    b3                   b4
        0.25                   0.25                  0.25                 0.25
                                         HIRS
                     IWT PRT Count to Temperature Coefficients
   PRT                a0            a1            a2            a3             a4
      1          301.38795 6.52106E-03 8.27531E-08 4.65675E-11 1.45893E-15
      2          301.37735 6.53105E-03 8.36999E-08 4.66502E-11 1.44768E-15
      3          301.39698 6.52318E-03 8.26203E-08 4.65039E-11 1.51146E-15
      4          301.36675 6.52655E-03 8.36699E-08 4.67894E-11 1.41383E-15
                                          SSU
                         PRT Count to Temperature Coefficients
             a0                            a1                          a2
          284.125                      4.819E-03                    8.75E-09
                         Thermistor to Temperature Coefficients
         b0                     b1                    b2                   b3
      375.969                -203.161              179.13                -85.16
         c0                     c1                    c2                   c3
      375.969                -203.161              179.13                -85.16
                                         MSU
                                                   1-84           NOAA POD GUIDE - 11/98 Revision
        PRT Resistance to Temperature Coefficients
        K0                                      495.6
        K1                                      107.8
         PRT Resistance to Temperature coefficients
                  e0                   e1                  e2
1A            29.003197             .429363           .3144484E-04
2A            28.514892            .4280371           .3028803E-04
1B            28.455605             .428430           .3021258E-04
2B            29.113998             .425768           .3159801E-04
                  Radiance of Space (Nsp)
      Channel                            Nsp(mW/sr-m2-cm-1)
         1                                    0.000086
         2                                    0.000096
         3                                    0.000084
         4                                    0.000092




Figure 1.4.10-1. Spectral Response Curve NOAA-14 AVHRR Channel-1




                                   1-85        NOAA POD GUIDE - 11/98 Revision
Figure 1.4.10-2. Spectral Response Curve NOAA-14 AVHRR Channel-2




                                  1-86        NOAA POD GUIDE - 11/98 Revision
                             Figure 1.4.10-3.
Figure 1.4.10-3. Spectral Response Curve NOAA-14 AVHRR Channel-3




                                  1-87        NOAA POD GUIDE - 11/98 Revision
Figure 1.4.10-4. Spectral Response Curve NOAA-14 AVHRR Channel-4




                                  1-88        NOAA POD GUIDE - 11/98 Revision
       Figure 1.4.10-5. Spectral Response Curve NOAA-14 AVHRR Channel-5


Users of SSU data should note that the quality indicator for invalid blackbody position is
always set on NOAA-14. Users should ignore this condition, assume the data are good
and proceed with processing as usual.




                                          1-89         NOAA POD Guide - Jan. 2002 Revision89
2.0            Level 1b Data Base

This section describes the NOAA Polar Orbiter Level 1b Data Base that is archived by
SSB, and from which users may request data.

Level 1b (following FGGE terminology) is raw data that have been quality controlled,
assembled into discrete data sets, and to which Earth location and calibration information
have been appended (but not applied).

The data are present on the data base as a collection of data sets. Each data set contains
data of one type for a discrete time period. Thus, there are separate HRPT, LAC, GAC,
HIRS, MSU, and SSU data sets. Time periods are arbitrary subsets of orbits, and may
cross orbits (i.e., may contain data along a portion of an orbital track that includes the
ascending node, the reference point for counting orbits). Generally, GAC, HIRS, MSU,
and SSU data sets will be available for corresponding time periods and usually have a
three to five minute overlap between consecutive data sets.

Prior to June 1981, the Earth location data in the AVHRR and TOVS Level 1b data may
have been slightly inaccurate due to errors in the TIROS Information Processor (TIP)
clock onboard the spacecraft. The 6-byte time code in the Level 1b data is taken from the
TIP clock which routinely contained errors of 1.5 to 2.3 seconds.

Some problems have been encountered with NOAA-10 and NOAA-11 AVHRR Level 1b
GAC data in regards to earth locations, distances between adjacent scan lines, data gaps,
scan line numbers, and out of sequence scan times. It is not known at this time if these
problems existed with the earlier spacecraft in the TIROS-N series. NESDIS/IPD is
investigating these problems and will take corrective action. The following paragraphs
summarize a memorandum from Karl W. Cox (SMSRC) to Pat Mulligan
(NOAA/NESDIS/OSD) which details the problems. Copies of this memorandum are
available from SSB.

As the spacecraft moves through its orbit, the expected angular distance between the
nadir of adjacent GAC scans is approximately 0.0296 degrees of arc, or 3.2914 km, as
measured from the center of the earth. This actual value of the average angular distance
can vary by up to about 0.1712 km due to variations in satellite height, scan angle and
other factors. Forty-eight randomly selected NOAA-10 and NOAA-11 GAC data sets
were examined over a period of a few days at the beginning of July 1990. On the
average, the distances between adjacent scan lines were outside the permitted window
(+/-0.2304 km) 45 times per dataset. The time difference between these adjacent scan
lines was the expected 500 milliseconds, but the quality flags did not indicate a data gap.

When data gaps occur in GAC data, the scan line number is supposed to be incremented
to reflect the number of scan lines corresponding to the length of the gap. However, the
first scan line after a data gap was found to have the scan number next in sequence of
those preceding the gap, while the second scan line following the gap had been
incremented by the number of scan lines corresponding to the data gap. On an average,



                                            2-1         NOAA POD Guide - Jan. 2002 Revision1
data gaps were found to occur two to three times per dataset with the gaps typically
ranging from one to 40 scan lines.

In four out of the 48 GAC data sets examined, scan times were encountered which were
not in proper sequence. Some of the time differences were very large. This problem
introduces earth locations markedly different from those of adjacent scan lines.
However, the scan line numbers were in ascending sequence as if there were no problems
with the scan times or earth locations, and no scan quality flags had been set.

In the past, SSB has attempted to give the user only data with calibration information, but
it was found that most users preferred to receive all the data (with or without calibration
information) over their area and/or time span. The user can then use his discretion in
applying the calibration coefficients to any gaps of data without calibration information.
It is SSB's policy that all Level 1b data (whether it includes calibration information
or not) will be provided to the user for his specific area or time unless explicitly
requested otherwise by the user.

In the event that the user receives data without calibration information, the data can be
calibrated from the telemetry information contained in each scan. For a detailed
explanation of this procedure, refer to NOAA Technical Memorandum NESS 107
entitled Data Extraction and Calibration of TIROS-N/NOAA Radiometers, available from
SSB. In the case of a data set with some calibration present, the user can usually
interpolate the calibration data between known points for the uncalibrated portion.

2.0.1          Clock Information

Users of Level 1b data should be aware that the satellite's on board clock experiences a
small drift in time over a period of several months. Specifically, that time drift can be
defined by Δt , where Δt is the spacecraft clock time (t) minus the actual UTC time.
SOCC monitors this time error and maintains Δt to within +/- 0.5 seconds. The Earth
location data which is appended to the Level 1b data is based on the spacecraft clock
time. Therefore, an error in Δt will be reflected as an error in Earth location. The error in
Earth location due to this timing error could be as much as 4 kilometers at the satellite
subpoint. SOCC normally applies the time correction around 2359 UTC on the
scheduled date. The clock error, drift rate, last update and future update are announced in
the APT Predict Bulletin (TBUS - TIROS Bulletin U.S.). The Level 1b process has been
enhanced to incorporate a clock drift correction option. See Appendix L for details.
Figure 2.0.1-1 shows a typical drift of Δt (note that points A and B are where SOCC
applies the correction to Δt).




                                            2-2         NOAA POD Guide - Jan. 2002 Revision2
                         Figure 2.0.1-1. Typical Time Drift Δt

2.0.2          IBM Conventions

All the NOAA polar orbiter Level 1b data and products are produced on IBM
mainframes. This section describes some of the characteristics of data written on an IBM
mainframe. The bit and byte numbering conventions are described, in addition to the
representations for signed binary integers and floating point numbers. These conventions
are especially critical if the user does not use an IBM machine to read the data. This does
not imply that these data cannot be read on non-IBM machines, but the user should
exercise some caution when reading "IBM-generated" data on a non-IBM machine.

The bit and byte (one byte equals 8-bits) numbering convention for Level 1b data sets is
as follows. The bits within each byte or word are numbered from the most significant bit
(MSB) on the left to the least significant bit (LSB) on the right, with the MSB identified
as bit 31, the next most significant as bit 30, and with the LSB as bit 0. Similarly, the
byte containing the 8 MSBs of a 32-bit word is identified as byte 4; and the byte
containing the 8 LSBs, as byte 1.

IBM's signed binary integers are usually represented as halfwords (16 bits) or words (32
bits). In both lengths, the leftmost bit (bit 31) is the sign of the number. The remaining
bits (bits 1-15 for halfwords and 1-31 for words) are used to designate the magnitude of



                                            2-3         NOAA POD Guide - Jan. 2002 Revision3
the number. Binary integers are also referred to as fixed-point numbers, because the
radix point (binary point) is considered to be fixed at the right, and any scaling is done by
the programmer.

Positive binary integers are in true binary notation with a zero sign bit. Negative binary
integers are in two's-complement notation with a one bit in the sign position. In all cases,
the bits between the sign bit and the leftmost significant bit of the integer are the same as
the sign bit (that is, all zeros for positive numbers, all ones for negative numbers).
Negative binary integers are formed in two's-complement notation by inverting each bit
of the positive binary integer and adding one.

A floating point number is expressed as a hexadecimal fraction multiplied by a separate
power of 16. The term floating point indicates that the placement, of the radix
(hexadecimal) point, or scaling, is automatically maintained by the machine.

The part of a floating-point number which represents the significant digits of the number
is called the fraction. A second part specifies the power (exponent) to which 16 is raised
and indicates the location of the radix point of the number. The fraction and exponent
may be represented by 32 bits.

A floating-point number has two signs: one for the fraction and one for the exponent.
The fraction sign, which is also the sign of the entire number, is the leftmost bit of each
format (0 for plus, 1 for minus). The numeric part of the fraction is in true notation
regardless of the sign. The numeric part is contained in bits 8-31.

The exponent sign is obtained by expressing the exponent in excess-64 notation; that is,
the exponent is added as a signed number to 64. The resulting number is called the
characteristic. It is located in bits 1-7. The characteristic can vary from 0 to 127,
permitting the exponent to vary from -64 through 0 to +63. This provides a scale
multiplier in the range of 16-64 to 16+63. A nonzero fraction, if normalized, has a value
less that one and greater than or equal to 1/16, so that the range covered by the magnitude
of a normalized floating-point number is between 16-65 and 16+63.

2.0.3                  Level 1b Data Set Names

This section describes the data set naming convention which is used for all Level 1b data
sets. Each data set has a unique data set name which is generated when the data set is
created. This 42-character name (which is coded in binary coded decimal [BCD]) will be
used to reference the data sets. The data set name will be "NSS" followed by a set of
alphanumeric qualifiers separated by periods (.). The complete data set name with all its
qualifiers will be as follows:

NSS.DATA-TYPE.SPACECRAFT-UNIQUE-ID.YEAR-DAY.START-TIME.STOP-TIME.PROCESSING-BLOCK-ID.SOURCE

The qualifiers of the data set name are shown in Table 2.0.3-1.




                                             2-4         NOAA POD Guide - Jan. 2002 Revision4
                   Table 2.0.3-1. Data set name qualifiers.
  Qualifier                                 Example
DATA-TYPE     Valid groups are:
              HRPT= HRPT (direct readout full resolution AVHRR)
              GHRR= GAC (recorded reduced resolution AVHRR)
              LHRR= LAC (recorded HRPT AVHRR)
              HIRX= HIRS/2 data set derived from GAC embedded TIP
              MSUX= MSU data set derived from GAC embedded TIP
              SSUX= SSU data set derived from GAC embedded TIP
              HIRS= HIRS/2 data set derived from stored TIP
              MSUS= MSU data set derived from stored TIP
              SSUS= SSU data set derived from stored TIP
SPACECRAFT-
UNIQUE-ID     TIROS-N = TN
              NOAA-A = NA = NOAA-6
              NOAA-B = NB
              NOAA-C = NC = NOAA-7
              NOAA-D = ND = NOAA-12
              NOAA-E = NE = NOAA-8
              NOAA-F = NF = NOAA-9
              NOAA-G = NG = NOAA-10
              NOAA-H = NH = NOAA-11
              NOAA-I = NI = NOAA-13
              NOAA-J = NJ = NOAA-14
YEAR-DAY      D76104, where "D" identifies this group as a Julian day delimiter, "76"
              identifies the year in which the spacecraft began recording the data set
              and "104" identifies the Julian day on which the spacecraft began
              recording the data set.
START-TIME    S1355, where "S" identifies this group as a start time delimiter. "1355"
              denotes 13 hours 55 minutes UTC (to the nearest minute) and represents
              the time at which spacecraft recording began.
STOP-TIME     E1456, where "E" identifies this group as an end time delimiter. "1456"
              denotes 14 hours 56 minutes UTC (to the nearest minute) and represents
              the time of spacecraft recording of the last usable data in the data set.
PROCESSING-   B0016465, where "B" identifies this group as a processing block ID
BLOCK-ID      delimiter. "0016465" is a seven digit number identifying the spacecraft
              revolution in which recording of this data set began and the revolution in
              which the data was transmitted to ground (the first five digits identifying
              the beginning revolution and last two being the two least significant
              digits of the orbit number identifying the readout revolution). However,
              NESDIS does not necessarily guarantee that the Processing-Block-ID
              contains the correct beginning and ending orbit number. Frequently
              (especially with LAC data), the orbit numbers are 1 to 2 off the correct
              orbit; thus, it is always prudent when ordering data to include a time, if
              known.
SOURCE        Valid character groups are:


                                   2-5         NOAA POD Guide - Jan. 2002 Revision5
                      Fairbanks, Alaska (formerly Gilmore Creek) = GC
                      Western Europe CDA = WE
                      SOCC (Satellite Operations Control Center) = SO
                      Wallops Island, Virginia = WI

2.0.4                 Data Set Header

This section describes the Data Set Header. All Level 1b data sets (with the exception of
the SBUV/2) contain a Data Set Header record describing the data set. This header
record is in binary and padded with trailing spare bytes to make it the same size as the
full channel data set records. (Note: The Data Set Header for HRPT and LAC data sets
is contained in two 7400-byte records. The first record contains the Data Set Header as
described below and the second record will be meaningless to the user.) Currently, there
are two slightly different Data Set Headers: one for the AVHRR and one for the TOVS
data. The Data Set Header for TOVS has changed slightly from the original. Its format
is given in Table 2.0.4-1.

    Table 2.0.4-1. Data set Header Record Format for TOVS (after September 8, 1992).
       Byte #             # Bytes                               Content
 1                   1                Spacecraft ID
 2                   1                Data Type
 3-8                 6                Start Time
 9-10                2                Number of scans
 11-16               6                End Time
 17-23               7                Processing Block ID (ASCII)
 24                  1                Ramp/Auto Calibration
 25-26               2                Number of Data gaps
 27-32               6                DACS Quality
 33-34               2                Calibration Parameter ID
 35                  1                DACS Status
 36                  1                Reserved for mounting and fixed attitude correction
                                      indicator:
                                       0 = no correction applied
                                       1 = correction applied
 37                  1                Nadir earth location tolerance. Integer scaled to 0.1
                                      km, values range from 0.1 to 25.5 km.
 38                  1                Spare (Zero-filled)
 39-40               2                4-digit year for start of data (effective December 2,
                                      1998)
 41-82               42               42 character dataset name (EBCDIC)
 83-84               2                Blank-filled
 85-end              variable         Zero-filled with enough bytes to make Header Record
                                      same size as data record.




                                           2-6        NOAA POD Guide - Jan. 2002 Revision6
SSB uses specialized software to extract parts of Level 1b datasets, based on user=s
selection criteria (channel, area and/or time selects). As of July 3, 1996, SSB modified
the extraction software so that the Data Set Header record would reflect the actual
number of output scan lines within the subsetted dataset and not the total number of scan
lines found in the original dataset. This change does not affect users who order tape
copies of entire datasets, just the users that order extracts.

The Data Set Header format was modified on two different occasions: Sept. 8, 1992 and
Nov. 15, 1994. Appendix K contains the original format (before Sept. 8, 1992) of the
Data Set Header, while Appendix L contains the interim format (between Sept. 8, 1992
and Nov. 15, 1994) of the Data Set Header.

The current Data Set Header format for AVHRR data includes orbital parameters that
were implemented with other enhancements on Nov. 15, 1994. The format for the
AVHRR Data Set Header is given in Table 2.0.4-2.

     Table 2.0.4-2. Data Set Header record format for AVHRR (after Nov. 15, 1994).
  Byte #      # of                              Contents                           Scaling
             bytes                                                                 Factor
 1         1         Spacecraft ID                                               n/a
 2         1         Data Type                                                   n/a
 3-8       6         Start Time                                                  n/a
 9-10      2         Number of scans                                             n/a
 11-16     6         End Time                                                    n/a
 17-23     7         Processing Block ID (ASCII)                                 n/a
 24        1         Ramp/Auto Calibration                                       n/a
 25-26     2         Number of data gaps                                         n/a
 27-32     6         DACS Quality                                                n/a
 33-34     2         Calibration Parameter ID                                    n/a
 35        1         DACS Status                                                 n/a
 36        1         Reserved for mounting and fixed attitude correction         n/a
                     indicator:
                      0 = no correction applied
                      1 = correction applied
 37        1         Nadir earth location tolerance. Integer scaled to 0.1 km,   n/a
                     values range from 0.1 to 25.5 km.
 38        1         Spare (Zero-filled)                                         n/a
 39-40     2         4-digit year for start of data (effective December 2, 1998) n/a
 41-84     44        44 character dataset name (EBCDIC)                          n/a
 85-86     2         2-digit year of Epoch for orbit vector (4-digit year        n/a
                     effective December March 17, 1999)
 87-88     2         Julian Day of Epoch (XXX)                                   n/a
 89-92     4         Millisecond UTC epoch time of day (XXXXXXXX)                n/a
                                Keplerian Orbital Elements
 93-96     4         Semi-major axis in kilometers                               1000


                                           2-7         NOAA POD Guide - Jan. 2002 Revision7
 97-100     4          Eccentricity                                                   100000000
 101-104    4          Inclination (in degrees)                                       100000
 105-108    4          Argument of Perigee (in degrees)                               100000
 109-112    4          Right Ascension of the Ascending Node (in degrees)             100000
 113-116    4          Mean Anomaly (in degrees)                                      100000
                          Cartesian Inertial True of Date Elements
 117-120 4             x component of position vector (in kilometers)                 10000
 121-124 4             y component of position vector (in kilometers)                 10000
 125-128 4             z component of position vector (in kilometers)                 10000
 129-132 4             x -dot component of position vector (in kilometers)            1000000
 133-136 4             y -dot component of position vector (in kilometers)            1000000
 137-140 4             z -dot component of position vector (in kilometers)            1000000
                                           Future Use
 141-142 2             Yaw fixed error correction                                     n/a
 143-144 2             Roll fixed error correction                                    n/a
 145-146 2             Pitch fixed error correction                                   n/a
 147-end variable Spares - zero filled to the size of the data record                 n/a
 Note: orbit parameters are scaled to 4-byte integers (not 8-byte floating point).

Valid spacecraft IDs are contained in Table 2.0.4-3. Note that the spacecraft ID is
identical for NOAA-11 and TIROS-N. In this case, users should use the time code in
conjunction with the spacecraft ID to verify that they have the correct satellite.

                                 Table 2.0.4-3. Spacecraft ID.
                  ID Number                                           Satellite
 0                                                 Spare
 1                                                 TIROS-N
 2                                                 NOAA-6
 4                                                 NOAA-7
 6                                                 NOAA-8
 7                                                 NOAA-9
 8                                                 NOAA-10
 1                                                 NOAA-11
 5                                                 NOAA-12
 2                                                 NOAA-13
 3                                                 NOAA-14

The data type of the data set is identified by the two integer codes contained in Table
2.0.4-4.

                                Table 2.0.4-4. Data Type Codes.
                    Bits 4-7                                           Bits 0-3
         Code                   Data Type                  Code                TIP Source
 1                        LAC                               1               Embedded TIP


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 2                         GAC                                  2              Stored TIP
 3                         HRPT                                 3              Third CDA TIP
 4                         TIP                                4-15             Spare
 5                         HIRS/2                              n/a             n/a
 6                         MSU                                 n/a             n/a
 7                         SSU                                 n/a             n/a
 8                         DCS                                 n/a             n/a
 9                         SEM                                 n/a             n/a
 10-15                     Spare                               n/a             n/a

The start time is the spacecraft time code from the first frame of data processed for this
data set and is contained in 6 bytes. The year is contained in the leftmost 7 bits of the
first two bytes, the 9-bit Julian day is right-justified in the first two bytes, and the 27-bit
millisecond UTC time of day is right-justified in the last four bytes. All other bits are
zero. Figure 2.0.4-1 shows the format of the time code for both start and end times.
Complete scans that fall within data gaps are not included in the number of scans count.
A gap in the data that covers one or more consecutive scans is counted as one data gap.

                Byte n Byte n+1 Byte n+2 Byte n+3 Byte n+4 Byte n+5
              |.......|.......|.......|.......|.......|.......|
              |<-Year>|<--Julian->|   |<---UTC time (milliseconds)----->|
                           Day
                (7 bits) (9 bits)                (27 bits)



       Figure 2.0.4-1. Format of the Time Code for both Start and Stop Times

The end time is the spacecraft time code from the last frame of data processed for this
data set. The content and format are the same as described for the start time (see Figure
2.0.4-1).

The Processing Block ID is a seven-byte field generated from start and end times. It
contains the spacecraft revolution in which recording of the data set began and the
revolution in which it terminated (same as the Processing Block ID described in
beginning of Section 2.0.3).

The ramp/auto calibration field is contained in one byte. Bits 4-8 of this byte have
meaning for GAC, LAC, and HRPT data sets only. These bits indicate ramp non-
linearity. Bit 3 of this byte has meaning only for HIRS/2 and SSU data sets and contains
the setting of the auto calibration override switch. Bit 4 is used for channel 1, bit 5 for
channel 2, etc.

The DACS quality field consists of six types of DACS (Data Acquisition and Control
Subsystem) quality information accumulated in the headers of all data sets derived from
data input from DACS. The first two bytes contain a count of the input data frames that


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contained no frame sync word errors. The second two bytes contain a count of the DACS
detected TIP parity errors. The last two bytes contain a sum of all auxiliary sync errors
detected in the input data for the complete data set.

The calibration parameter ID identifies the calibration parameter input data set which is
used to calibrate the data in this data set. The ID is encoded internally as a string of two
8-bit characters; not as an integer number.

DACS status information comprises one byte and is contained in the header of all data
sets derived from data input from DACS. This byte is described in Table 2.0.4-5.

                        Table 2.0.4-5. DACS Status Information Format.
            Bits                          Value                          Meaning
             7                Pseudo Noise (P/N) Flag
                              0                              Normal Data
                              1                              P/N Data
             6-5              Data Source
                              0                              Unused
                              1                              Fairbanks
                              2                              Wallops
                              3                              SOCC
              4               Tape Direction
                              0                              REV (time decrementing)
                              1                              FWD (time incrementing)
              3               Data Mode
                              0                              Test Data
                              1                              Flight Data
             2-0              Spare

2.1               Level 1b Tape Formats

This section describes the general structure of a magnetic tape containing Level 1b data.
Section 2.1.1 describes the record and file arrangement of Level 1b data tapes. For
information regarding the data format of a specific type of Level 1b data, see Section 3
for AVHRR data and Section 4 for TOVS data.

SSB offers the user data written on several different types of magnetic media. These
media include IBM 3480 cartridges, 4 mm DAT tapes and 8 mm Exabyte tapes. (Nine-
track 800, 1600 and 6250 BPI tapes are no longer available.)

There are also several selection options available to the user. It is possible to obtain a full
data set copy, or just a portion of a data set (specified by an area and/or time). In
addition, channels can also be selected and the data can be unpacked. (Selection of data
by channels automatically results in data which is in the 16-bit unpacked format.)




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SSB uses specialized software on all Level 1b data (except for SBUV/2 data). This
software creates a small header record at the beginning of the file which is known as the
TBM header and is described in detail in Section 2.1.1. Level 1b tapes in SSB's archive
do not contain a TBM record, although any Level 1b tape sent to a user by SSB will
contain a TBM record.

Data sets may be stacked sequentially on tape. If a data set extends across two tapes
(split data set), there will be an end of file (EOF) on the first tape and a double EOF after
the last data set on the second tape. Note: there will not be any headers before the data
on the second tape. User's software, when detecting end of medium while reading data
records, should request the next tape and resume reading the records of the current data
set. If a user cannot handle split data sets, the area of interest must be reduced through
some selection process.

Unless otherwise requested, all Level 1b tapes generated by SSB will be written with
TBM Header, packed data, and no split data sets. For example, if a user wants three
full data set copies of LAC data on 3480 cartridges, the first two data sets will be placed
on Tape 1 and the third will be placed on Tape 2 (rather than splitting the third data set
across two tapes). See Table 2.3-2 for the volume of data available on IBM 3480
cartridges.

2.1.1          Record and File Structure

Each copy of a Level 1b data set will be written on tape as a separate file (a series of
records followed by an EOF). Regardless of whether a full copy or area, time, or channel
selection is made, the following format applies.

The record structure of each file (data set) except LAC/HRPT is as shown below:

        Record 1:    TBM (Terabit memory) Header record (122 bytes)
        Record 2:    Data Set Header record
        Records 3-n: Data records

However, the above record structure does not hold true for any LAC/HRPT data sets.
These particular data sets contain two data records for each scan. Each record has 7,400
bytes; therefore, the Data Set Header Record is also contained in two 7,400-byte records
(the first record contains the Data Set Header and the second record is meaningless). The
record structure of each file for LAC/HRPT data sets is as follows:

        Record 1:      TBM Header record (122 bytes)
        Record 2:      Data Set Header record (7,400 bytes)
        Record 3:      Dummy (7,400 bytes)
        Records 4-n:   Data records (7,400 bytes)

The above tape format also applies to data received from SSB prior to April 1985 when
the TBM system was shut down. These data always included a TBM Header Record



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since they were accessed using the TBM. Currently, SSB's software creates a TBM
Header record directly from operator input of the data set name and selection criteria.
Users can verify which selection criteria were used by checking the TBM Header record.

The TBM Header contains information as to the type of data, selection parameters used,
etc. The TBM Header record is 122 bytes in length and all fields are ASCII characters
except the Channels Selected field which is in binary. The format for the TBM Header
record is contained in Table 2.1.1-1.

                         Table 2.1.1-1. TBM Header Record Format.
         Byte #             # of Bytes in Field                    Contents
 31-74                  44                         Data Set Name
 75                     1                          Total/Selective Copy (AT@ or AS@)
 76-78                  3                          Beginning Latitude
 79-81                  3                          Ending Latitude
 82-85                  4                          Beginning Longitude
 86-89                  4                          Ending Longitude
 90-91                  2                          Start Hour
 92-93                  2                          Start Minute
 94-96                  3                          Number of Minutes
 97                     1                          Appended Data Selection (AY@ or
                                                   AN@)
 98-117                 20                         Channels Selected (in binary)
 118-119                2                          Sensor Data Word Size (ASCII)

The data set name is in the same format as described in Section 2.0.3. The
total/selective copy field is one byte long and contains either a "T" or an "S" for total or
selective copy, respectively.

The beginning and ending latitude and longitude fields give the range of latitude and
longitude if either or both were selected. If the latitude or longitude select option is not
used, these fields will have "ALL" coded in them to indicate all latitudes or longitudes.

The start hour and minute fields indicate the beginning time of the selected data set.
The number of minutes field indicates the number of minutes contained in the selected
data set. "AL" indicates there was no time selection, and all times were included.

The appended data selection field indicates whether or not Earth location was appended
to the data. Appended data are always included with any Level 1b data obtained from
SSB. This is indicated by a "Y" in the field for Yes.

The channels selected field contains 20 bytes corresponding to 20 possible channels.
The value of each byte can be either 0 or 1. If the data have been selected by channel,
then byte 75 will contain an "S" for Select and there will be a 1 in each appropriate
channel position in the channels selected field. If the total dataset has been chosen, byte


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75 will contain a "T" for Total and there will be a 0 in each channel position. The
channel number is indicated by the position of the byte (e.g., Channel 4 would be found
in byte 4 of the field). However, channel select HIRS data are not ordered
chronologically from 1 to 20. They are in the order indicated in Section 4.1.2.1 (i.e., byte
2 would indicate Channel 17, etc.).

The sensor data word size field contains 2 bytes in ASCII which indicate the size of the
sensor data words in the dataset. Valid values are 08, 10 or 16; which corresponds to 8
bit (unpacked), 10 bit (packed) and 16 bit (unpacked) formats, respectively.

Table 2.1.1-2 contains the character code conversion from hexadecimal to ASCII code.
This may be useful when reading the TBM Header Record.

The format of the Data Set Header is described in Section 2.0.4. Note that the Data Set
Header Record will always contain the same number of bytes as a full channel data
record. For full data set copies, the format of each type of data record is described in
Sections 3 and 4 for AVHRR and TOVS, respectively.

                    Table 2.1.1-2. Character Code Conversion (ASCII).
      HEX           ASCII           HEX          ASCII         HEX                      ASCII
 OD              CR             41            A             4F                      O
 20              SP             42            B             50                      P
 2B              +              43            C             51                      Q
 2E              .              44            D             52                      R
 30              0              45            E             53                      S
 31              1              46            F             54                      T
 32              2              47            G             55                      U
 33              3              48            H             56                      V
 34              4              49            I             57                      W
 35              5              4A            J             58                      X
 36              6              4B            K             59                      Y
 37              7              4C            L             5A                      Z
 38              8              4D            M             5F                      -
 39              9              4E            N

2.2            Level 1b Data Record Formats

This section describes two general types of data formats which can be obtained from
SSB. The first format is the most commonly used and is called the packed data format.
The packed format is the format in which the data are archived by SSB. It takes up the
least amount of tape but is more difficult to use because of its' compressed nature. This
format is described in Section 2.2.1. The second format is known as the "16-bit
unpacked format" and is described in Section 2.2.2. It consists of the video (channel)
data being "unpacked" into two 16-bit words in four bytes (32 bits), right justified. When




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the data is selected by channel, the format will automatically be the "16-bit unpacked"
format.

2.2.1           Packed Data Format

The packed data format is the standard format in which the data are received from
NESDIS and in which they are ultimately archived by SSB. It is the default if the user
does not request a specific format. Because of the sheer volume of satellite data, the
packed data format is preferred for storing large quantities of data. However, due to the
method of packing, it is more difficult to write software to handle this data. Basically,
the packed data format contains the data arranged with as few spaces or gaps between the
data elements as possible. This means that it is usually not possible to directly read the
data on word or halfword boundaries.

In the case of the AVHRR data, the video (channel) data are packed as three 10-bit
samples in four bytes, right-justified. The first two bits of each four-byte group are zero.
The channels are interleaved, so the samples have the following order: scan point 1
(Channels 1, 2, 3, 4, 5), scan point 2 (Channels 1, 2, 3, 4, 5), etc. The detailed packed
data format can be found in Section 3.1.2.1 for GAC data and in Section 3.2.2.1 for
LAC/HRPT data. Appendix B should be helpful in unpacking this data format. Figure
2.2.1-1 illustrates the packed data format for AVHRR data.

   Bytes |<--------4----->|<------3------->|<-----2-------->|<-----1------->|

   Bits     .3.3.2.2.2.2.2.2.2.2.2.2.1.1.1.1.1.1.1.1.1.1.9.8.7.6.5.4.3.2.1.0.
            .1.0.9.8.7.6.5.4.3.2.1.0.9.8.7.6.5.4.3.2.1.0. . . . . . . . . . .

                     Scan Point 1     Scan Point 1        Scan Point 1
            |0 0|<----Channel 1--->|<---Channel 2--->|<---Channel 3--->|
                      (10 bits)          (10 bits)          (10 bits)


                 Figure 2.2.1-1 Packed Data Format for AVHRR Data


Since the TOVS data are generated by three distinct instruments, their packed data format
is more complex and will not be discussed here. For detailed information on the TOVS
packed data format, refer to Sections 4.1.2.1, 4.2.2.1, and 4.3.2.1 for the HIRS/2, SSU,
and MSU data, respectively.

2.2.2           16-bit Unpacked Data Format

The 16-bit unpacked data format is an ideal format for the occasional satellite data user
with a small area and period of interest. The video data are unpacked into two 16-bit
words (INTEGER*2 words) in four bytes using SSB's software. The channel data are
contained in the ten least significant bits and the six most significant bits are zero-filled.


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This unpacked data format requires more storage on magnetic tape but considerably less
investment in software development. The specific formats for the 16-bit unpacked data
format vary according to data type and are fully described in the "Full Data Set Copy"
subsection for each data type in Sections 3 and 4. Figure 2.2.2-1 illustrates the 16-bit
unpacked data format for AVHRR data.

      Bytes |<----4--------->|<-------3------>|<-------2------>|<-------1----->|

      Bits    .3.3.2.2.2.2.2.2.2.2.2.2.1.1.1.1.1.1.1.1.1.1.9.8.7.6.5.4.3.2.1.0.
                      .1.0.9.8.7.6.5.4.3.2.1.0.9.8.7.6.5.4.3.2.1.0.

                               Scan point 1            Scan point 1
              |0 0 0 0 0 0|<---Channel 1---->|0 0 0 0 0 0|<---Channel 2--->|
                                (10 bits)                       (10 bits)


                  Figure 2.2.2-1 Unpacked Data Format for AVHRR Data

2.3               Data Volume per Tape

This section contains information concerning the size of data records for each instrument,
the amount of data (in minutes) which will fit on an IBM 3480 cartridge, and the normal
lengths (in minutes) of each type of data set. The approximate amount of data requested
can also be computed by determining the number of minutes over a specific area using
the spinner described in Section 1.2.

Table 2.3-1 shows the record length (in bytes) for each type of instrument, depending on
whether the data desired is full copy or channel select. It also shows the number of
records per scan and number of scans per minute for each instrument. Note that the
record length of packed TOVS data is actually larger than the unpacked TOVS because
the channel selection software eliminates portions of the original TOVS data that were
deemed unnecessary when the software was written in 1978. SSB does not recommend
channel selection for TOVS Level 1b data.

Table 2.3-2 contains the number of minutes of each type of Level 1b data (with the
exception of SBUV/2 data) for full copy or channel select in the packed and unpacked
data format which can be written onto an IBM 3480 cartridge.

Typical lengths of data sets in minutes are approximately 110 minutes for GAC and all
TOVS data sets, 11 to 13 minutes for HRPT, and 10 minutes for LAC.

                     Table 2.3-1. Level 1b Data Record Length (Bytes).
  Data            1        2            3        Full    Full Copy         Comments
  Type        Channel Channels Channels          Copy    Unpacked
                                                Packed
 GAC          2,536   4,168        5,808       6,440     9,080         2 scans/record,


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                                                                       120 scans/minute
LAC/     2,272     4,320      6,368        7,400         10,464        2 records/scan,
HRPT                                                                   360 scans/minute
HIRS/2   1,492     1,604      1,716        4,253         3,620         1 record/scan,
                                                                       9.4 scans/minute
MSU      204       228        256          437           280           1 record/scan,
                                                                       2.3 scans/minute
SSU      308       436        564          2,498         564           1 record/scan,
                                                                       1.9 scans/minute

       Table 2.3-2. Level 1b IBM 3480 Cartridge Volume (Minutes/Cartridge).
 Data Type     1 Channel      2 Channels   3 Channels    Full Copy     Full Copy
                                                           Packed      Unpacked
GAC           625            455          358           330           251
LAC/HRPT      55             37           28            24            18
HIRS/2        5,214          5,045        4,888         2,864         3,194
MSU           34,537         34,114       33,960        31,029        33,292
SSU           40,000         37,931       35,610        20,000        35,610




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3.0            AVHRR Level lb Data Base

This section contains more specific information on the AVHRR instrument. Section 3.1
describes the GAC data characteristics and the tape formats available (full copy, selective
extracts, and unpacked format). Similarly, Section 3.2 contains specific information
about LAC/HRPT data. Section 3.3 describes the calibration procedures for AVHRR
data (both visible and thermal). NESDIS has instituted several improvements to the
original Level 1b format. The current enhancement and resulting data format is
detailed in this section, with previous enhancements detailed in Appendices K and
L.

3.0.1          AVHRR Instrument Description

The Advanced Very High Resolution Radiometer (AVHRR) represents an improvement
over the VHRR sensor flown aboard the ITOS series of operational satellites (the last of
which was-NOAA-5). The AVHRR is a cross-track scanning system similar to the
VHRR, but features four or five spectral channels, compared to just two for the VHRR.
The AVHRR flown aboard TIROS-N, NOAA-6, NOAA-8, and NOAA-10 has four
channels, and the AVHRR aboard NOAA-7, NOAA-9, NOAA-11, NOAA-12 and
NOAA-13 has five channels. Subsequent satellites in the series will have five. Provision
has been made for five channels in the data format for all satellites. Channel 5 contains a
repeat of Channel 4 data, when only four different channels are available.

The spectral band widths (in micrometers) of the AVHRR channels for the TIROS-N
series and those proposed for the remaining spacecraft are shown in Table 3.0.1-1. In
addition, the Instantaneous Field of View (IFOV) in milliradians (mr) is included for each
channel in Table 3.0.1-1. The spectral response functions for each satellite are contained
in the figures in Section 1.4.

           Table 3.0.1-1. Spectral band widths (micrometers) of the AVHRR.
                              NOAA-6,-8,        NOAA-7,-9,                                  IFOV
 Channel #   TIROS-N          -10               -11,-12,-14      NOAA-13                    (mr)
 1           0.55-0.90        0.58-0.68         0.58-0.68        0.58-0.68                  1.39
 2           0.725-1.10       0.725-1.10        0.725-1.10       0.725-1.0                  1.41
 3           3.55-3.93        3.55-3.93         3.55-3.93        3.55-3.93                  1.51
 4           10.5-11.5        10.5-11.5         10.3-11.3        10.3-11.3                  1.41
 5           Channel 4        Channel 4         11.5-12.5        11.4-12.4                  1.30
             repeated         repeated

The IFOV of each channel is approximately 1.4 mr leading to a resolution at the satellite
subpoint of 1.1 km for a nominal altitude of 833 km. The scanning rate of the AVHRR is
360 scans per minute. The time within each scan line of AVHRR data represents IFOV
#1.

The analog data output from the sensors is digitized on board the satellite at a rate of
39,936 samples per second per channel. Each sample step corresponds to an angle of


                                            3-1         NOAA POD Guide - Jan. 2002 Revision1
scanner rotation of 0.95 mr. At this sampling rate, there are 1.362 samples per IFOV. A
total of 2048 samples will be obtained per channel per Earth scan, which will span an
angle of 55.4 degrees from the nadir (subpoint view).

The IR channels are calibrated in-flight using a view of a stable blackbody and space as a
reference. No in-flight visible channel calibration is performed (although the spaceview
is available as one reference point). Although these will vary from instrument to
instrument, the design goals for the IR channels were an NEdT (Noise Equivalent
differential Temperature) of 0.12 K (@ 300 K) and a S/N (signal to noise ratio) of 3:1 @
0.5% albedo.

Users should be aware that AVHRR Channel 3 data on each-TIROS-N series spacecraft
have been very noisy due to a spacecraft problem and may be unusable, especially when
the satellite is in daylight.

As a result of the design of the AVHRR scanning system, the normal operating mode of
the satellite calls for direct transmission to Earth (continuously in real-time) of AVHRR
data. This direct transmission is called HRPT, for High Resolution Picture Transmission.
In addition to the HRPT mode, about ten minutes of data may be selectively recorded on
each of two recorders on board the satellite for later playback. These recorded data are
referred to as LAC (Local Area Coverage) data. LAC data may be recorded over any
portion of the world as selected by NOAA/NESDIS and played back on the same orbit as
recorded or during a subsequent orbit. LAC and HRPT data have identical formats.

The full resolution data is also processed on board the satellite into GAC (Global Area
Coverage) data which is recorded only for readout by CDA stations. GAC data contains
only one out of three original AVHRR lines and the data volume and resolution are
further reduced by starting with the third sample along the scan line, averaging the next
four samples, and skipping the next sample. The sequence of average four, skip one, is
continued to the end of the scan.

3.1            GAC Data

This section describes the data characteristics and magnetic tape format of Global Area
Coverage (GAC) data. Section 3.1.1 contains the data characteristics and Section 3.1.2
contains the tape formats available. The tape formats include the full data set copy, the
16-bit unpacked format, and the selective extract subsets. NESDIS has enhanced the
Level 1b format for GAC and the most recent format (for data collected after Nov.
15, 1994) is included in this section. Previous formats are included in Appendices K
and L.

3.1.1          Data Characteristics

The processor on board the satellite samples the real-time AVHRR data to produce
reduced resolution GAC data. Four out of every five samples along the scan line are used
to compute one average value, and the data from only every third scan line are processed.



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As a result, the spatial resolution of GAC data near the subpoint is actually 1.1 km by 4
km with a 3 km gap between pixels across the scan line, although generally treated as 4
km resolution. All of the GAC data computed during a complete pass are recorded on
board the satellite for transmission to Earth on command. The 10-bit precision of the
AVHRR data is retained.

3.1.2           Magnetic Tape Formats

The data set format for full data set copies (all channels) is different from the format for
selective extract subsets (selected channels). Sections 3.1.2.1 and 3.1.2.2 contain formats
for GAC full data set copies and GAC selective extract subsets, respectively. Section
3.1.2.1 also includes an explanation of the 16-bit unpacked data format.

3.1.2.1         Full Data Set Copies

Each GAC data set contains an individual satellite recorder playback (or a portion of a
playback if there is an interruption in the data due to noise, etc., in which case a single
playback may be fragmented into a number of data sets). Data within each GAC data set
is in chronological order with one logical record per scan. Two logical records are
written per 6440-byte physical record. Each logical record contains 3220 bytes written in
binary format as shown in Table 3.1.2.1-1. This table contains the format of the GAC
data record which was implemented on Nov. 15, 1994.

      Table 3.1.2.1-1. Format of GAC data record (implemented November 15, 1994).
     Byte #       # of bytes                               Contents
 1-2             2            Scan line number from 1 to n
 3-8             6            Time code (year, day, hour, minute, second)
 9-12            4            Quality indicators (see Table 3.1.2.1-2)
 13-52           40           Calibration coefficients
 53              1            Number of meaningful zenith angles and Earth location points
                              appended to scan (n)
 54-104          51           Solar zenith angles
 105-308         204          Earth location
 309-448         140          Telemetry (HRPT minor frame format)
 449-3176        2728         GAC video data
 3177-3196       20           Additional decimal portion of 51 solar zenith angles
 3197-3198       2            Clock drift delta in milliseconds x 2 + indicator:
                              0 = no time adjustment
                              1 = time adjustment
 3199-3220       22           Spare

The time code consists of the year, Julian day, and UTC time of day in milliseconds.
The year is contained in the first 7 bits of the first two bytes, the 9-bit day of year is right-
justified in the first two bytes and the 27-bit millisecond UTC time of day is right-
justified in the last four bytes. All other bits are zero. The time code will always have
the same format for all Level 1b data sets.


                                              3-3          NOAA POD Guide - Jan. 2002 Revision3
The quality indicators are contained in four bytes. The first byte contains processing
detected conditions and the last three bytes contain DACS quality indicators. If bit is one
(on), then condition is true. The format of the quality bytes is contained in Table 3.1.2.1-
2.

                       Table 3.1.2.1-2. Format of quality indicators.
     Byte #      Bit #                                  Contents
               7          FATAL FLAG - Data should not be used for product generation
               6          TIME ERROR - A time sequence error was detected while
                          Processing this frame
               5          DATA GAP - A gap precedes this frame
               4          DATA JITTER - Resync occurred on this frame
 9             3          CALIBRATION - Insufficient data for calibration
               2          NO EARTH LOCATION - Earth location data not available
               1          ASCEND/DESCEND - AVHRR Earth location indication of
                          Ascending (=0) or descending (=1) data
               0          P/N STATUS - Pseudo Noise (P/N) occurred (=1) on the frame,
                          data not used for calibration computations
               7          BIT SYNC STATUS - Drop lock during frame
               6          SYNC ERROR - Frame Sync word error greater than zero
               5          FRAME SYNC LOCK - Frame Sync previously dropped lock
               4          FLYWHEELING - Flywheeling detected during this frame
               3          BIT SLIPPAGE - Bit slippage detected during this frame
               2          CHANNEL 3 SOLAR BLACKBODY CONTAMINATION
                          (SBBC) INDICATOR
 10                       0 = no correction
                          1 = solar contamination corrected
               1          CHANNEL 4 SBBC INDICATOR
                          0 = no correction
                          1 = solar contamination corrected
               0          CHANNEL 5 SBBC INDICATOR
                          0 = no correction
                          1 = solar contamination corrected
               7          TIP PARITY - In first minor frame
               6          TIP PARITY - In second minor frame
               5          TIP PARITY - In third minor frame
 11
               4          TIP PARITY - In fourth minor frame
               3          TIP PARITY - In fifth minor frame
               0-2        SPARE
 12            2-7        SYNC ERRORS - Number of bit errors in frame sync
               0-1        SPARE




                                            3-4         NOAA POD Guide - Jan. 2002 Revision4
The calibration coefficients consist of slope and intercept values for each of the five
channels. The use of these coefficients is described in Section 3.3. Each value is stored
in four bytes in the following order:

       Channel 1 slope coefficient
       Channel 1 intercept coefficient
       Channel 2 slope coefficient
       Channel 2 intercept coefficient
       Channel 3 slope coefficient
       Channel 3 intercept coefficient
       Channel 4 slope coefficient
       Channel 4 intercept coefficient
       Channel 5 slope coefficient
       Channel 5 intercept coefficient

A fixed number of zenith angles and Earth location points are appended to each scan.
However, only the first n zenith angles and the first n Earth location points have
meaningful values (n is defined in byte #53). The maximum number of points possible in
a scan is 51. There are 409 points in a GAC scan line. However, the solar zenith angles
and Earth location data (latitude and longitude) are sampled every eight points starting at
the fifth point (5, 13, 21,..., 389, 397, 405). There are 51 possible solar zenith angles and
Earth location values for each scan line. Each zenith angle requires one byte and is
stored as degrees x 2. The latitude and longitude values are each stored in two-byte fields
in 128ths of a degree (0 to 180E positive, 0 to 180W negative). See Section 2.0.1 for
explanation of negative binary integers in two's-complement notation.

The telemetry data contain information which may be used to compute calibration
coefficients when these are not included in the data. The telemetry data are stored in 140
bytes. The first 103 (10 bit) words are packed three (10 bit) words in four bytes, right
justified. The last four byte group contains one (10 bit) word with 20 trailing bits. All
unused bits are set to zero. The contents of these 103 words are contained in Table
3.1.2.1-4, which is the entire HRPT minor frame format. For more information, refer to
NOAA Technical Memorandum NESS 107 entitled, Data Extraction and Calibration of
TIROS-N/NOAA Radiometers.

The GAC video data consist of five readings (one for each channel) for each of the 409
points in a scan. They are packed as three (10-bit) samples in four bytes, right-justified.
The last four-byte group contains two (10-bit) samples with 10 trailing zero bits. The
first two bits of each four-byte group are zero. The 2,045 samples (409 points x 5
channels) are ordered scan point 1 (Channel 1, 2, 3, 4, 5), scan point 2 (Channel 1, 2, 3, 4,
5), etc., which is also known as Band Interleaved by Pixel (BIP). Note for TIROS-N,
NOAA-6, NOAA-8, and NOAA-10, there is no sensor for Channel 5 so Channel 4 data is
repeated in the Channel 5 position. The video data are stored in binary. See Figure
2.2.1-1 for the arrangement of the GAC channels (packed format).




                                            3-5         NOAA POD Guide - Jan. 2002 Revision5
Enhancements implemented on Sept. 7, 1994, included clock drift corrections and orbit
parameters format change from IBM real numbers to scaled integers. These
enhancements were made to both the TOVS and AVHRR Level 1b data. However, the
new system did not function properly for AVHRR and was removed the same day with
the old process resumed. Problems were encountered with the data record time codes in
the GAC Level 1b data and NESDIS was forced to remove the updates from the AVHRR
processing. Initially, NESDIS tried turning off the clock drift corrections, but time codes
were still incorrect so the old process was resumed. The AVHRR data were processed
with the old on-line earth location software until updates could be reinstalled. The
following list of orbits were affected for the AVHRR:

NOAA-12
    clock corrections on:
    HRPT - S1542.E1550.B1722626.GC
    LHRR - S1402.E1402.B1722525.GC (time sequence errors)
    GHRR - S1359.E1539.B1722526.GC
    LHRR - S1359.E1411.B1722525.GC
    LHRR - S0934.E0946.B1722222.GC
    HRPT - S1902.E1914.B1722828.GC

       clock corrections off:
       GHRR - S1723.E1900.B1722728.GC
       GHRR - S1534.E1727.B1722627.GC
       LHRR - S1729.E1738.B1722727.GC
       LHRR - S1652.E1658.B1722627.GC
       LHRR - S1532.E1543.B1722626.GC

NOAA-11
    clock corrections on:
    HRPT - S1722.E1734.B3068787.GC
    GHRR - S1542.E1719.B3068687.GC
    GHRR - S1353.E1547.B3068586.GC
    LHRR - S1516.E1527.B3068586.GC
    LHRR - S1342.E1353.B3068585.GC

NOAA-9
    clock corrections on:
    GHRR - S0825.E1019.B5019596.WI
    GHRR - S0128.E0321.B5019092.WI

On November 15, 1994, NESDIS re-implemented the following changes to the Level 1b
GAC data stream: 1) Current orbital parameters in the header were switched to four byte
integers rather than 8 byte floating point numbers. 2) Calibration algorithms were
updated to remove the effects of sunlight impinging on the internal calibration target
(Solar Blackbody Contamination - SBBC). SBBC detection indicators were added to the
AVHRR data record quality indicators. 3) Navigation software was updated to remove



                                            3-6        NOAA POD Guide - Jan. 2002 Revision6
satellite clock errors from the data time codes. 4) Navigation quality control parameters
were provided in the header record.

An anomalous dip occurs in the AVHRR Channel 3 blackbody counts between 70S and
80S latitude shortly after the spacecraft comes out of eclipse but only for sun angles less
than 25 degrees above the horizon. This dip, which produces an anomalous increase in
the calibration gain coefficient, has been attributed to reflected sunlight impinging onto
the internal calibration target (ICT). Evidence suggests that this dip may have occurred
in all of the afternoon satellites in the current NOAA series.

When SBBC is detected, the slope and intercept are replaced by the running average of
the twenty-four previous good values. If no checking is done, the value is set to zero.
Currently, only NOAA-11 shows this contamination. On Dec. 1, 1993, AVHRR gain
anomaly corrections were implemented for NOAA-11 beginning with data set:
NSS.GHRR.NH.D93335.S1408.E1554.B2673132.GC. However, for 24 hours, the
following datasets for NOAA-12 were affected:
NSS.GHRR.ND.D93335.S1303.E1457.B1324445.GC through
NSS.GHRR.ND.D93336.S0535.E0729.B1325455.WI.

The drift in the onboard TIP clock for each polar satellite introduces a timing error in the
instrument data time codes. This error is reflected as an along-track Earth location error.
SOCC measures this error and corrects it periodically to maintain a maximum of
approximately  0.5 seconds. Under Phase II of the navigation enhancements, SOCC
error corrections will be used to adjust the instrument time codes and eliminate its Earth
location error effect. The adjusted values will be stored in the scan data record and an
indicator flag will be set for users. Consequently, users are apprized of the magnitude of
the adjustment and also have the flexibility of removing the correction, if needed.

This enhancement also results in improved navigation parameters. The operational
quality control (QC) of Earth location data will be improved. A nadir Earth location
tolerance value will be used to indicate when the Earth location data are beyond an
acceptable range. An independent calculation of the latitude and longitude values at
nadir will be compared to the operational values. This comparison will be performed
approximately four times per orbit. If differences are beyond the acceptable tolerance
range, a "BAD EARTH LOCATION" flag is set, and a message identifying the scan is
generated. The Earth location tolerance range will be provided in the header record as an
integer, scaled to 0.1 km (ranges from 0.1 to 25.5). If no checking is done, the value is
set to zero.

See Table 2.0.4-2 for the current format of the Level 1b header record which was
implemented Nov. 15, 1994.

The 16-bit unpacked format for full copy GAC data has the same format as the "packed"
data described above except for the video data. The video data values for each channel
are contained in the 10 least significant bits and the 6 most significant bits are zero filled.




                                              3-7         NOAA POD Guide - Jan. 2002 Revision7
  The record length is 4540 bytes. Table 3.1.2.1-3 contains the format for the unpacked
  GAC video data (for all five channels).

             Table 3.1.2.1-3. Format of unpacked GAC video data (five channels).
   Point #        Byte #          Bit #                          Content
   1                          10-15        Zero filled
              449-450         0-9          1st value of Channel 1
                              10-15        Zero filled
              451-452         0-9          1st value of Channel 2
              453-454         0-9          1st value of Channel 3
              455-456         0-9          1st value of Channel 4
              457-458         0-9          1st value of Channel 5
   2          459-460         0-9          2nd value of Channel 1
   ...        ...             ...          ...
   409        4537-4538       0-9          409th value of Channel 5
              4539-4540       0-15         Zero filled (so record will be on word boundary)

                  Table 3.1.2.1-4. HRPT Minor Frame Format.
Function           No. of    Word     Bit No. Plus Word Code &
                   Words Position 1 2 3 4 5 6 7 8 9 10 Meaning
Frame Sync         6         1        1010000100
                             2        0101101111
                             3        1 1 0 1 0 1 1 1 0 0 See Note 1.
                             4        0110011101
                             5        1000001111
                             6        0010010101
ID (AVHRR)         2         7        Bit 1: 0=Internal Sync; 1=AVHRR Sync
                                      Bits 2 & 3; 00=Not used; 01=Minor Frame #1;
                                      10=Minor Frame #2; 11=Minor Frame #3
                                      Bits 4-7; Spacecraft Addresses; Bit 4=MSB,
                                      Bit7=LSB
                                      Bit 8; 0=Frame Stable; 1=Frame resync occurred
                                      Bits 9-10; spare; bit 9=0, bit 10=1
                             8        Spare word; bit symbols undefined
Time Code          4         9        Bits 1-9; Binary day count; Bit 1=MSB;
                                      Bit 9=LSB
                                      Bit 10; 0; spare
                             10       Bits 1-3; all zeroes; spare 1, 0, 1
                                      Bits 4-10; Part of binary msec of day count;
                                      Bit 4=MSB of msec count
                             11       Bits 1-10; Part of binary msec of day count;
                             12       Bits 1-10; Remainder of binary msec of day
                                      count; Bit 10=LSB of msec count
Telemetry (AVHRR) 10         13       Ramp Calibration AVHRR Channel #1
                             14       Ramp Calibration AHVRR Channel #2


                                            3-8         NOAA POD Guide - Jan. 2002 Revision8
                                15         Ramp Calibration AHVRR Channel #3
                                16         Ramp Calibration AHVRR Channel #4
                                17         Ramp Calibration AHVRR Channel #5
                                18         PRT Reading 1
                                19         PRT Reading 2 See Note 2.
                                20         PRT Reading 3
                                21         AVHRR Patch Temperature
                                22         0 0 0 0 0 0 0 0 0 1 Spare
Internal Target Data   30       23         10 words of internal target data from each
(AVHRR)                                    AVHRR channel 3, 4 and 5. These data are time
                                           multiplexed as chan 3 (word 1), chan 4 (word 1),
                                           chan 5 (word 1), chan 3 (word 2),
                                           chan 4 (word 2), chan 5 (word 2), etc.
Space Data             50       53 thru    10 words of space scan data from each AVHRR
(AVHRR)                         102        channel 1,2,3,4, and 5. These data are time
                                           multiplexed as chan 1 (word 1), chan 2 (word 1),
                                           chan 3 (word 1), chan 4 (word 1),
                                           chan 5 (word 1), chan 1 (word2),
                                           chan 2 (word 2), chan 3 (word2),
                                           chan 4 (word 2), chan 5 (word 2), etc.
Sync Δ (AVHRR)         1        103        Bit 1; 0=AVHRR sync early; 1=AVHRR sync
                                           late,
                                           Bits 2-10; 9 bit binary count of 0.9984 MHz
                                           periods; Bit 2=MSB, Bit 10=LSB
TIP data               520      104 thru   The 520 words contain five frames of TIP data
                                623        (104 TIP data words/frame). See Note 3.
                                           Bits 1-8: Exact format as generated by TIP
                                           Bit 9: Even parity check over bits 1-8
                                           Bit 10: -bit 1.
Spare Words            127      624        1010001110
                                625        1110001011
                                626        0000101111
                                627        1011000111
                                628        1101010010
                                ...        ... See Note 4
                                748        1001011010
                                749        1100100010
                                750        1000000000
Earth Data (AVHRR)     10,240   751        Chan 1 - Sample 1
                                752        Chan 2 - Sample 1
                                753        Chan 3 - Sample 1
                                754        Chan 4 - Sample 1
                                755        Chan 5 - Sample 1
                                756        Chan 1 - Sample 2



                                           3-9        NOAA POD Guide - Jan. 2002 Revision9
                                   ...        ...See Note 5
                                   10,985     Chan 5 - Sample 2047
                                   10,986     Chan 1 - Sample 2048
                                   10,987     Chan 2 - Sample 2048
                                   10,988     Chan 3 - Sample 2048
                                   10,989     Chan 4 - Sample 2048
                                   10,990     Chan 5 - Sample 2048
Auxiliary Sync          100        10,991     1111100010
                                   10,992     1111110011
                                   10,993     0110110101
                                   10,994     1010111101
                                   ...        ...See Note 6
                                   11,089     0111110000
                                   11,090     1111001100
Notes:
1) First 60 bits from 63 bit PN generator started in the all 1's state. The generator polynomial
is X6+X5+X2+X+1
2) AVHRR Internal Target Temperature Data. Three readings from one of the four platinum
resistance thermometers (PRT). Each of these words is a 5 channel subcom, 4 words of IR
data plus a subcom reference value.
3) 104 words includes 103 words of the AMSU frame plus the first word of TIP.
4) Derived by inverting the output of a 1023 bit PN sequence provided by a feedback shift
register generating the polynomial: X10+X5+X2+X+1. The generator is started in all 1's state
at the beginning of word 7 of each minor frame.
5) Each minor frame contains the data obtained during one Earth scan of the AVHRR sensor.
The data from the five sensor channels of the AVHRR are time multiplexed as indicated.
6) Derived from the non-inverted output of a 1023 bit PN sequence provided by a feedback
shift register generating the polynomial: X10+X5+X2+X+1. The generator is started in the
all 1's state at the beginning of word 10,991.

  3.1.2.2        Selective Extract Subsets

  The following sections describe the data set format for GAC data sets which have been
  produced using channel selection (16-bit format) or by choosing the 8-bit format offered
  by SAA. Section 3.1.2.2.1 describes the 16-bit format and Section 3.1.2.2.2 describes the
  8-bit format. SSB is aware of a problem which affects the format of both the 8-bit and
  the 16-bit (unpacked) data for the Level 1b AVHRR. The problem involves the omission
  of 22 bytes of extra precision information containing the Solar Zenith angle and clock
  drift delta in each record. These bytes were added to the Level 1b data record (on
  October 24, 1992) after the extraction software was written, and were therefore not
  included. If users of the 8- or 16-bit format data want this extra precision data, they are
  only available if the user requests packed format output from the SAA=s online archive
  of Level 1b data sets.

  3.1.2.2.1              16-bit format


                                            3-10         NOAA POD Guide - Jan. 2002 Revision10
When channels are selected for GAC data, the format is identical to that described in
Section 3.1.2.1 except for the GAC video data. In the GAC video data, the selected
channels are packed in consecutive half words (16 bits). The data values for each
channel selected are contained in the ten least significant bits and the remaining six most
significant bits are zero filled. The GAC video data have the format shown in Table
3.1.2.2.1-1 when two channels are selected.

                 Table 3.1.2.2.1-1. Format for GAC video data (two channels).
     Point #        Byte #         Bit #                            Content
 1              449-450        10-15        Zero-filled.
                               0-9          First value, First selected channel.
 2              451-452        10-15        Zero-filled.
                               0-9          First value, Second selected channel.
 3              453-454        10-15        Zero-filled.
                               0-9          Second value, First selected channel.
 4              455-456        10-15        Zero-filled.
                               0-9          Second value, Second selected channel.
 ...            ...            ...          ...
 409            2083-2084      10-15        Zero-filled.
                               0-9          409th value, Second selected channel.

The total record length for the two channel selective GAC would be 4168 bytes (2 x
2084, since there are 2 scans/record) with no spare bytes trailing. Similarly, if one
channel was selected the record would contain 820 bytes (409 points/scan + 1 (to make a
whole word) x 2 bytes/point) for the GAC video, which would make the entire record
2536 bytes long (2 x 1268).

3.1.2.2.2              8-bit format

When the 8-bit format is chosen (from SAA), the normal 10-bit video data are truncated
to 8-bits. (The 2 least significant bits of data are dropped.) The format is identical to that
described in Section 3.1.2.1 except for the GAC video data. In the GAC video data, the
data are packed in consecutive bytes (four data points per 32-bit word). Because there
are an odd number of data points (409) in the video data, the last three bytes are zero
filled in order to pad the data to a full word boundary. The GAC video data have the
format shown in Table 3.1.2.2.2-1.

               Table 3.1.2.2.2-1. 8-bit format for GAC video data (one channel).
   Word #          Point #       Byte #        Bit #                   Content
 113             1             449         0-7        First video data value (First scan).
                 2             450         0-7        Second video data value (First scan).
                 3             451         0-7        Third video data value (First scan).
 ...             ...           ...         ...        ...
 214             408           856         0-7        408th video data value (First scan).


                                           3-11         NOAA POD Guide - Jan. 2002 Revision11
 215             409          857          0-7          409th video data value (First scan).
                              858          0-7          Zero filled.
                              859          0-7          Zero filled.
                              860          0-7          Zero filled.
 216                          860-762      0-15         Scan line number (Second scan).
 ...             ...          ...          ...          ...
 327             1            1309         0-7          First video data value (Second scan).
                 2            1310         0-7          Second video data value (Second scan).
 ...             ...          ...          ...          ...
 429             408          1716         0-7          408th video data value (Second scan).
 430             409          1717         0-7          409th video data value (Second scan).
                              1718         0-7          Zero filled.
                              1719         0-7          Zero filled.
                              1720         0-7          Zero filled.

The record length for one channel selected GAC in the 8-bit format would be 1720 bytes
(2 x 860, since there are 2 scans/record) with the last three trailing bytes zero filled.

Similarly, a user may select channels and request them in the 8-bit format. The output
physical record length information for GAC is included in Table 3.1.2.2.2-2.

            Table 3.1.2.2.2-2. Output physical record length for GAC (in bytes).
                                    Packed: 6440 bytes
       # Channels Selected                         Unpacked: (in bytes)
                                       8-bit Format                  16-bit Format
 1                              1720                           2536
 2                              2536                           4168
 3                              3352                           5808
 4                              4168                           7440
 5                              4992                           9080

3.2            LAC/HRPT Data

This section describes the data characteristics and magnetic tape formats of Local Area
Coverage (LAC)/High Resolution Picture Transmission (HRPT) data. Section 3.2.1
contains the data characteristics and Section 3.2.2 contains the tape formats available.
The tape formats include the full data set copy, selective extract subsets, and the 16-bit
unpacked format which is available for all channels. NESDIS has enhanced the Level
1b format for LAC/HRPT and the current format (for data collected after Nov. 15,
1994) are included in this section. Previous formats are included in Appendices K
and L.




                                          3-12         NOAA POD Guide - Jan. 2002 Revision12
3.2.1                  Data Characteristics

The AVHRR data are digitized to 10-bit precision. The digitized data are both
transmitted from the satellite in real-time as High Resolution Picture Transmission
(HRPT) data, and selectively recorded on board the satellite for subsequent playback as
Local Area Coverage (LAC) data. A maximum of ten minutes of LAC data may be
recorded per orbit.

In the event that a user would want SOCC to schedule an AVHRR LAC orbit over a
specific area (out of direct readout range of Wallops Island or Fairbanks CDA's), the
procedures and requirements are contained in Section 1.3.

3.2.2          Magnetic Tape Formats

The data set format for full data set copies (all channels) is different from the format for
selective extract subsets (selected channels). Sections 3.2.2.1 and 3.2.2.2 contain formats
for LAC/HRPT full data set copies and selective extract subsets, respectively. Section
3.2.2.1 also includes an explanation of the 16-bit unpacked data format.

3.2.2.1        Full Data Set Copies

Each HRPT data set contains the HRPT data from one CDA contact. Each LAC data set
contains an individual satellite recorder playback (10 minutes of recorded HRPT data).
The data within each data set are in chronological order with one scan contained in two
physical records. The records are written in binary and contain 7,400 bytes in the format
shown in Table 3.2.2.1-1. This table includes the enhancements made on Nov. 15, 1994.

  Table 3.2.2.1-1. Format of LAC/HRPT data record (implemented November 15, 1994).
 Record #       Byte #      # Bytes                         Content
 1           1-2          2          Scan line number
             3-8          6          Time code
             9-12         4          Quality indicators
             13-52        40         Calibration coefficients
             53           1          Number of meaningful zenith angles and Earth
                                     location points appended to scan
             54-104       51         Solar zenith angles
             105-308      204        Earth location
             309-448      140        Telemetry (header)
             449-7400     6952       LAC/HRPT video data
 2           10-15704     6704       LAC/HRPT video data
             6705-6724    20         Additional decimal portion of 51 solar zenith angles
             6725-6726    2          Clock drift delta in milliseconds x 2 + indicator:
                                     0 = no time adjustment
                                     1 = time adjustment
             6727-7400    674        Spare


                                          3-13         NOAA POD Guide - Jan. 2002 Revision13
The content and order of the LAC/HRPT records is identical to the GAC record described
in Section 3.1.2.1, with the exception of three fields. The three exceptions are the solar
zenith angles, Earth location, and LAC/HRPT video data. Also, note that the calibration
coefficients are ordered Channels 1, 2, 3, 4, and 5, the same as GAC data. See Section
3.1.2.1 for translation of the time code.

There are 2,048 points in a LAC/HRPT scan line. The solar zenith angle and Earth
location data (latitude and longitude) are sampled every 40 points starting at point 25
(25, 65, 105,..., 1945, 1985, 2025). There are 51 possible zenith angles and Earth
location values for each scan line. Each solar zenith angle requires one byte and is stored
as degrees x 2. The latitude and longitude values are each stored in two-byte fields in
128ths of a degree (0 to 180E positive, 0 to 180W negative). See Section 2.0.2 for
explanation of negative binary integers in two's-complement notation.

The LAC/HRPT video data contain five values (one for each channel) for each of the
2,048 points in a scan (i.e., 2,048 points x 5 channels = 10,240 samples). The data are
packed as three (10-bit) words in four bytes, right-justified. The last four-byte group
contains two leading zero bits, one (10-bit) word, and 20 trailing zero bits. The first two
bits of each four-byte group are zero. The LAC/HRPT video data is ordered scan point 1
(Channel 1, 2, 3, 4, 5), scan point 2 (Channel 1, 2, 3, 4, 5), etc., which is also known as
Band Interleaved by Pixel (BIP). The video data are stored in binary. See Figure 2.2.1-1
for the arrangement of the LAC/HRPT channels (packed format).

The 16-bit unpacked format for full copy LAC/HRPT data has the same format as the
"packed" data described above, except for the video data. The video data are unpacked
into two 16-bit words in every four bytes. The data values for each channel are contained
in the ten least significant bits and the six most significant bits are zero filled. The format
for unpacked LAC/HRPT video data (for all five channels) is contained in Table 3.2.2.1-
2.

        Table 3.2.2.1-2. Format of unpacked LAC/HRPT video data (five channels).
 Point #    Record # Byte #            Bit #        Content
 1          1            449-450       10-15        Zero filled
                                       0-9          1st value of Channel 1
                         451-452       10-15        Zero filled
                                       0-9          1st value of Channel 2
                         453-454       0-9          1st value of Channel 3
                         455-456       0-9          1st value of Channel 4
                         457-458       0-9          1st value of Channel 5
 2          1            459-460       0-9          2nd value of Channel 1
 ...        ...          ...           ...          ...
 1002       1            10463-10464   0-9          1002nd value of Channel 3
 1002       2            1-2           0-9          1002nd value of Channel 4
 ...        ...          ...           ...          ...
 2048       2            10463-10464   0-9          2048th value of Channel 5


                                           3-14          NOAA POD Guide - Jan. 2002 Revision14
Note that one scan of unpacked LAC/HRPT data is contained in two 10,464 byte records.
(The decision was made to divide into two records because a 20,928 byte record may
have been too large for some smaller computers to handle.)

3.2.2.2        Selective Extract Subsets

This section describes the data set format for LAC/HRPT data sets which have been
produced using channel selection (16-bit format) or by choosing the 8-bit format offered
by SAA. Section 3.2.2.2.1 describes the 16-bit format and Section 3.2.2.2.2 describes the
8-bit format for LAC/HRPT data. SSB is aware of a problem which affects the format of
both the 8-bit and the 16-bit (unpacked) data for the Level 1b AVHRR. The problem
involves the omission of 22 bytes of extra precision information containing the Solar
Zenith angle and clock drift delta in each record. These bytes were added to the Level 1b
data record (on October 24, 1992) after the extraction software was written, and were
therefore not included. If users of the 8- or 16-bit format data want this extra precision
data, they are only available if the user requests packed format output from the SAA=s
online archive of Level 1b data sets.

3.2.2.2.1             16-bit format

When channels are selected for LAC/HRPT data, the format is identical to that described
in Section 3.2.3.1 except for the LAC/HRPT video data. For the LAC/HRPT video data,
the selected channels are packed in consecutive halfwords (16 bits). The data values for
each channel selected are contained in the ten least significant bits and the remaining six
most significant bits are zero filled. If one channel is selected, the LAC/HRPT video data
have the format shown in Table 3.2.2.2.1-1.

             Table 3.2.2.2.1-1. Format for LAC/HRPT video data (one channel).
     Point #       Byte #         Bit #                          Content
 1             449-450        10-15      Zero filled.
                              0-9        First value of selected channel.
 2             451-452        10-15      Zero filled.
                              0-9        Second value of selected channel.
 3             453-454        10-15      Zero filled.
                              0-9        Third value of selected channel.
 ...           ...            ...        ...
 2048          4543-4544      10-15      Zero filled.
                              0-9        2048th value of selected channel.

Note that all LAC/HRPT data set scans require two records regardless of the number of
channels selected. For an example of two channel selection for LAC/HRPT data, use the
GAC two-channel format in Section 3.1.2.2 as a guide.




                                         3-15         NOAA POD Guide - Jan. 2002 Revision15
3.2.2.2.2              8-bit format

When the 8-bit format is chosen (from SAA), the normal 10-bit video data are truncated
to 8-bits. (The 2 least significant bits of data are dropped.) The format is identical to that
described in Section 3.2.2.1 except for the LAC/HRPT video data. In the LAC/HRPT
video data, the data are packed in consecutive bytes (four data points per 32-bit word).
The LAC/HRPT video data have the format shown in Table 3.2.2.2.2-1.

             Table 3.2.2.2.2-1. Format for LAC/HRPT video data (one channel).
   Point #    Record #      Byte #       Bit #                    Content
 1           1            449        0-7        First video data value.
 2           1            450        0-7        Second video data value.
 3           1            451        0-7        Third video data value.
 ...         ...          ...        ...        ...
 2048        1            2498       0-7        2048th video data value.

Similarly, a user may select channels and request them in the 8-bit format. The output
record length information for LAC/HRPT is included in Table 3.2.2.2.2-2.

         Table 3.2.2.2.2-2. Output physical record length for LAC/HRPT (in bytes).
                                     Packed: 7400 bytes
      # Channels Selected                               Unpacked:
                                   8-bit Format (in bytes)       16-bit Format (in bytes)
 1                              1,248                          2,272
 2                              2,272                          4,320
 3                              ,296                           6,368
 4                              4,320                          8,416
 5                              5,344                          10,464

3.3            Calibration of AVHRR Data

AVHRR thermal data values (Channels 3 and 4, and 5 when present) may be converted to
temperature values; and AVHRR visible data values (Channels 1 and 2) may be
converted to albedos, by the calibration procedures described herein. For more detail on
how NESDIS calibrates the TIROS-N/NOAA-A through -J radiometers, refer to NOAA
Technical Memorandum NESS 107 which is entitled Data Extraction and Calibration of
TIROS-N/NOAA Radiometers.

The format and order of the calibration coefficients is described in Sections 3.1.2.1 and
3.2.2.1 for GAC and LAC/HRPT data, respectively. Once the calibration coefficients
have been extracted (see Appendix B), they must be scaled. The slope values must be
divided by 230 and the intercept values by 222. The scaled slopes and intercepts may now
be used as described below.




                                           3-16         NOAA POD Guide - Jan. 2002 Revision16
New calibration formulae and techniques for the NOAA-14 AVHRR may be examined in
depth in a paper by NOAA/NESDIS/ORA=s Dr. C.R. Nagaraja Rao which can be
accessed on the Internet at URL: http://orbit-net.nesdis.noaa.gov/ora/text/nrao02.txt. As
of November 1996, monthly AVHRR calibration coefficient updates for NOAA-14
Channels 1 and 2 have also been included at URL:
http://psbsgi1.nesdis.noaa.gov:8080/EBB/ml/niccal.html, as well as incorporated into the
Level 1b datasets. Another source of calibration information for the NOAA polar
orbiters can be found on a NOAA/NESDIS home page located at URL:
http://www.osdpd.noaa.gov/PSB/CALIB/home.html This page contains calibration
quality control monitoring for NOAA-14 and the NOAA KLM series.

3.3.1                 Thermal Channel Calibration

The scaled thermal channel slope values are in units of mW/(m2-sr-cm-1) per count and
the intercept is in mW/(m2-sr-cm-1).

The radiance measured by the sensor (Channel i) is computed as a linear function of the
input data values as follows:

                                 Ei = Si C + Ii                                    3.3.1-1

where Ei is the radiance value in mW/(m2-sr-cm-1), C is the input data value (ranging
from 0 to 1023 counts), and Si and Ii are respectively the scaled slope and intercept
values. The conversion to brightness temperature from radiance is performed using the
inverse of Planck’s radiation equation:

                                          C2                                      3.3.1-2
                            T(E) =
                                                 
                                     ln 1 + C1 
                                                3


                                              E 

where T is the temperature (K) for the radiance value E, υ is the central wave number of
the channel (cm-1), and C1 and C2 are constants (C1=1.1910659 x 10-5 mW/(m2-sr-cm-4)
and C2=1.438833 cm-K).

Note that the temperatures obtained by this procedure are not corrected for atmospheric
attenuation, etc.

The central wave numbers (cm-1) for Channels 3, 4, and 5 as a function of temperature
can be found for each satellite in Section 1.4.

The following example shows how the raw data values may be converted to temperature
values. Let the slope and intercept values for Channels 3 and 4 have the following
values:




                                          3-17        NOAA POD Guide - Jan. 2002 Revision17
                                                 S4 = - 171966195
                                                  S3 = - 1638538
                                                  I4 = 667267071
                                                    I3 = 6365951


Since these values are scaled they must be divided by the proper scale factor. The slope
values
must be divided by 230; therefore,

                         171966195
                S4 = -           30
                                               = - .160156 mW/(m2 - sr- cm-1)overcount
                                2
                                    1638538                     mW/(m2 - sr- cm-1)
                         S3 = -           30
                                                  = - .001526
                                      2                             count

Similarly, the intercept values must be divided by 222:

                                667267071
                         I4 =          22
                                                  = 159.088867mW/(m2 - sr- cm-1)
                                      2
                                    6365951
                          I3 =            22
                                                  = 1.517761mW/(m2 - sr- cm-1)
                                      2

Now, the video data for Channels 3 and 4 must be extracted from the tape. Assume the
data values for spot n are:

                                                  Channel 3 = 857
                                                 Channel 4 = 513
For spot n+1, assume the values are:

                                                  Channel 3 = 858
                                                 Channel 4 = 515


To convert these values into radiance values, the calibration coefficients must be applied
to the
data using Equation 3.3.1-1. Therefore, for Channel 4:

                                                               2        -1
            En = - .160156 x 513 + 159.088867 = 76.92883 mW/( m - sr- cm )

                                                                   2        -1
           En 1 = - .160156 x 51 5 + 159.088867 = 76. 60853 mW/( m - sr- cm )

And for Channel 3:



                                                      3-18          NOAA POD Guide - Jan. 2002 Revision18
                                                                2        -1
               E n = - .001526 x 857 + 1.517761 = .209979 mW/( m - sr- cm )

                                                                 2        -1
               En+1 = - .001526 x 858 + 1.517761 = .208453 mW/( m - sr- cm )

These radiance values can be converted to temperatures by use of Equation 3.3.1-2.
Assuming υ = 2638.05 cm-1 for Channel 3 and υ = 912.01 cm-1 for Channel 4, the
radiance values correspond to 273.94 K and 274.84 K for Channels 3 and 4, respectively.

3.3.1.1        Non-Linearity Corrections (TIROS-N through NOAA-12)

Pre-launch calibrations of the infrared and microwave channels are carried out in a
thermal vacuum chamber to minimize absorption of radiation in the path between the
source and the radiometer and to simulate conditions in space. The radiometer
sequentially views the warm calibrated laboratory blackbody (in place of the earth
"target"), a blackbody cooled to approximately 77 K (representing the cold space view),
and its own internal blackbodies. Temperatures of all blackbodies are sensed with
thermistors or platinum resistance thermistors (PRTs). Radiances for each channel can
be computed from those temperatures by the methods described in Section 3.3.1. Data
are collected as the laboratory blackbody is cycled through a sequence of temperature
plateaus approximately 10K apart between 175K and 320K, which spans the entire range
of earth target temperatures. The entire procedure is carried out independently for several
instrument operating temperatures (e.g., 10, 15 and 20 degrees C for the AVHRR) that
bracket the range of operating temperatures encountered in orbit. The operating
temperature is represented by the temperature of the instrument's baseplate, which is also
approximately the same as the temperature of its internal warm blackbody.

The instrument manufacturers and NESDIS independently analyze the data from the pre-
launch tests to determine operating characteristics of the instruments, such as their signal-
to-noise ratios, stability, linearity of response, and gain (output in digital counts per unit
incident radiance). However, these characteristics cannot be expected to remain the same
in orbit as they were before launch. One reason is that the thermal environment varies
with position in the orbit, causing gains to vary orbitally. Also, instrument components
age in the several years that usually elapse between the time of the pre-launch test and
launch, and the aging process continues during the two or more years the instrument
typically operates in orbit. Therefore, the TIROS/NOAA radiometers have been
designed to view cold space and one or more internal warm blackbodies as part of their
normal scan sequences in orbit. This provides data in the microwave and infrared
channels for determining signal-to-noise and radiometric slopes and intercepts.
Unfortunately, there are no on-board calibration sources for the visible region.
Therefore, the pre-launch calibration must be used for the visible channels.

There are other coefficients necessary for in-orbit calibration that must be derived from
pre-launch test data. These include the coefficients to account for the non-linearity in the
AVHRR's response, which will be described later in this section.



                                           3-19         NOAA POD Guide - Jan. 2002 Revision19
The pre-launch calibration relates the AVHRR's output, in digital counts, to the radiance
of the scene. In pre-launch tests, the scene is represented by the laboratory blackbody.
The calibration relationship is a function of channel and baseplate temperature. For
channel 3, which uses an InSb detector, the calibration is highly linear. However,
because channels 4 and 5 use HgCdTe detectors, their calibrations are slightly non-linear.

To characterize the calibration when the AVHRR is in orbit, the only data available are
those acquired when the AVHRR views space and the internal blackbody. This gives
two points on the calibration curve, sufficient to determine only a straight-line
approximation to the calibration. The linear approximation is what is applied to
determine scene radiances. Scene brightness temperatures are then derived via the
temperature-to-radiance look-up tables described in each spacecraft's respective
subsection of Section 1.4.

To account for non-linearities, NESDIS provides corrections in each spacecraft's
respective subsection of Section 1.4 that are added to the scene brightness temperatures
computed from the linear calibration. The corrections are tabulated against scene
temperatures, and there is a separate table for each channel and each baseplate
temperature. NESDIS derives the pre-launch test data as follows:

       a. A quadratic is fitted by least squares to the scene radiance VS. AVHRR output
       count data.

       b. The quadratic equation is applied to the AVHRR response, in counts, when it
       viewed its internal blackbody. This determines the radiance of the internal
       blackbody. In effect, the AVHRR itself is used to transfer the calibration of the
       laboratory blackbody to the internal blackbody. Note that no assumptions have
       been made about the emissivity of the internal blackbody.

       c. Using counts from the "view" of the cold target (whose radiance is assumed to
       be zero) and the internal target (whose radiance was determined in step b., the
       linear calibration equation is determined.

       d. The linear calibration is then applied to the AVHRR output, in counts,
       obtained when the AVHRR viewed the laboratory blackbody. This produces
       radiances, one for each of the temperature plateaus of the laboratory blackbody.
       The radiances are converted to brightness temperatures by the method described
       in NESS 107, Appendix A.

       e. The brightness temperatures are subtracted from the actual temperatures of the
       laboratory blackbody, determined from its PRTs. The differences are the
       correction terms.

It should be noted that the procedures outlined above were not used for TIROS-N,
NOAA-6, NOAA-7 and NOAA-8. For these spacecraft, the variation in the non-linearity
correction with internal blackbody temperature was not allowed for, and a negative



                                         3-20         NOAA POD Guide - Jan. 2002 Revision20
radiance of space, Nsp was introduced to minimize temperature errors in the range of 225-
310 K.

3.3.1.2        Non-Linearity Corrections (NOAA-13 and successors)

With the launch of NOAA-13, NESDIS changed its derivation of the non-linearity
correction in the calibration of AVHRR Channels 4 and 5. The linear calibration now
uses a negative, non-zero value for the radiance of space, instead of the former value of
zero. This method makes the dependence of the correction terms on the internal
calibration target negligible.

NESDIS continues to supply tables of brightness temperature correction terms for the
non-linearity. These correction terms are valid only when applied to "linear" brightness
temperatures based on the negative radiance of space. Since the correction terms no
longer vary with the internal calibration target temperature, the user does not need to
interpolate on the internal calibration target temperature. Otherwise, the user applies the
non-linearity corrections as before.

NESDIS also supplies an alternate method of handling the-non-linearity which can be
applied to radiances instead of brightness temperatures. For each instrument and for each
channel, three coefficients (A, B and D) of a quadratic equation are supplied in Section
1.4 for all spacecraft from NOAA-13 on. The following quadratic equation can be used
to compute the corrected radiance, RAD from the "linear" radiance, Rlin:

                            RAD = A x R lin + B x R lin 2 + D                      3.3.1.2-1

This new treatment of the non-linearity plot corrections should be an improvement over
the previous method because: 1) it is less sensitive to noise in the thermal/vacuum test
data, 2) it gives the user a choice of correcting either the radiance or the brightness
temperatures, and 3) it is being applied retrospectively in the NOAA/NASA Pathfinder
program (see URL: http://daac.gsfc.nasa.gov/DATASET_DOCS/avhrr_dataset.html for
more information) to generate a consistent time series of AVHRR radiances from 1981 to
the present for use in studies of climate change. Making the same method operational at
NESDIS will eliminate a source of inconsistency between the Pathfinder data set and
future observations.

3.3.2                  Visible Channel Calibration

The scaled visible channel slope values are in units of percent albedo/count for slope and
in percent albedo for intercept.

The percent albedo measured by the sensor channeli is computed as a linear function of
the input data value as follows:

                                   Ai = Si C + Ii                                    3.3.2-1



                                          3-21          NOAA POD Guide - Jan. 2002 Revision21
where Ai is the percent albedo measured by channel i, C is the input data value in counts,
and Si and Ii are respectively, the scaled slope and intercept values. The visible channels
(1 and 2) are calibrated using Equation 3.3.2-1 to obtain the percent albedo.

The calibration procedure is very similar to the linear calibration procedure described
above for the thermal channels. The pre-launch slopes and intercepts for AVHRR
Channels 1 and 2 are shown in Table 3.3.2-1.

     Table 3.3.2-1. Pre-launch slopes and intercepts for AVHRR Channels 1 and 2.
    Satellite            S1               I1             S2              I2
 TIROS-N              0.1071             -3.9          0.1051           -3.5
 NOAA-6               0.1071           -4.1136         0.1058         -3.4539
 NOAA-7               0.1068           -3.4400         0.1069          -3.488
 NOAA-8               0.1060           -4.1619         0.1060         -4.1492
 NOAA-9               0.1063           -3.8464         0.1075         -3.8770
 NOAA-10              0.1059           -3.5279         0.1061         -3.4766
 NOAA-11              0.0906            -3.730         0.0900          -3.390
 NOAA-12              0.1042           -4.4491         0.1014         -3.9925
 NOAA-13              0.1076           -3.9747         0.1035         -3.8280
 NOAA-14*             0.1081           -3.8648         0.1090         -3.6749

 * Beginning with NOAA-14 in November 1996, the slopes and intercepts for AVHRR
 Channels 1 and 2 were computed monthly, incorporated into the Level 1b datasets and posted
 on the NOAASIS home page (URL:
 http://psbsgi1.nesdis.noaa.gov:8080/EBB/ml/niccal.html).

The two visible channels on the AVHRR instrument are calibrated prior to launch using
the following procedure: the calibration source is a large-aperture integrating sphere
equipped with 12 calibrated quartz-halogen lamps. These lamps were carefully selected
to match each other as closely as possible in spectral output and operating current. The
sphere is then calibrated with all 12 lamps on against a National Institute of Standards
and Technology secondary standard of spectral irradiance. The ratio of the output of n
lamps to that of 12 lamps is also determined. This yields the spectral output of the sphere
when any number of lamps, n, is on. By varying the number of bulbs which are turned
on, a calibration curve from dark level to a maximum of 12 lamps output can be obtained.

The following computations must be made in order to present the calibration in terms of
percent albedo vs. radiometer output. First, the spectral output of the sphere is integrated
with the spectral response function of the AVHRR channel to yield an effective radiance
for the spectral band for 12 lamps operating. This is then multiplied by the appropriate
Kn factor to convert to n lamps. This is described by equation 3.3.2-2:

                                           2

                                  NL = K n  C( )  ( ) d                          3.3.2-2
                                           1




                                          3-22           NOAA POD Guide - Jan. 2002 Revision22
where,

NL             =     effective radiance as seen by the channel in the appropriate spectral
               band.

Kn             =       the factor to convert to radiance for n lamps.

C(λ)           =       calibrated spectral radiance of the sphere with 12 lamps on.

 λ             =       wavelength, in the spectral region λ1 to λ2

φ(λ)           =       the measured spectral response of the channel being calibrated.

Similarly, if one takes the solar irradiance at the top of the atmosphere and performs a
similar calculation, the results are shown in Equation 3.3.2-3.

                                          2
                                      1
                               Ns =
                                          S( )  ( ) d                                 3.3.2-3
                                          1


where,

Ns             =       effective radiance of the radiometer viewing reflected sunlight.

S(λ )          =       spectral irradiance viewed at the top of the atmosphere.

Φ(λ)     =     spectral response function of the channel.

The resultant Ns represents what would be “seen” from space with a 100% reflecting,
diffuse surface when the solar zenith angle is zero.

                                                NL
                                          A=       x 100                                    3.3.2-4
                                                NS

Thus, the percent lbedos A is calculated using Equation 3.3.2-4:
To convert from percent lbedos A to spectral radiance R (in W/(m2-micrometer-sr) ),
the following equation must be used:

where,
                                   F   
                            R=A                                                            3.3.2-5
                               100  W 
                                        

F              =      integrated solar spectral irradiance, weighted by the spectral
               response function of the channel in W/m2.

W              =       equivalent width of the spectral response function in micrometers .


                                               3-23            NOAA POD Guide - Jan. 2002 Revision23
Table 3.3.2-2 contains the values of W and F derived from Neckel and Labs (1984).

                Table 3.3.2-2. Values of W and F for AVHRR Channels 1 and 2.
    Satellite               W1                F1             W2              F2
 TIROS-N              0.325             443.3          0.303         313.5
 NOAA-6               0.109             179.0           0.223         233.7
 NOAA-7               0.108             177.5          0.249         261.9
 NOAA-8               0.113             183.4          0.230         242.8
 NOAA-9               0.117             191.3          0.239         251.8
 NOAA-10              0.108             178.8          0.222         231.5
 NOAA-11              0.113             184.1          0.229         241.1
 NOAA-12              0.124             200.1          0.219         229.9
 NOAA-13              0.121             194.09         0.243         249.42
 NOAA-14              0.136             221.42         0.245         252.29

Although the pre-launch calibration procedures are quite extensive, it is not sufficient to
rely on these calibration data alone to achieve the desired accuracy from AVHRR data.
The instrument characteristics cannot be expected to remain the same in orbit as they
were before launch. This situation occurs primarily because the thermal environment
varies with the satellite's position in orbit, causing the output in digital counts to vary.
Initially, Channels 1 and 2 are observed to degrade in orbit because of the outgassing and
launch associated contamination (Rao and Chen, 1994). Continued exposure to the harsh
space environment (Brest and Rossow, 1992) is also a contributing factor. In addition,
the instrument's components age in the years that elapse between the pre-launch tests and
actual launch. Furthermore, this aging process continues during the two or more years
that the instrument is typically operational.

Unfortunately, there are no onboard calibration sources for the visible channels and the
pre-launch calibration must be used or the user must rely on ground-based experimental
techniques for deriving the calibration equations. NOAA and the National Aeronautics
and Space Administration (NASA) recognized the inherent problems with the AVHRR
data and collaborated to form the NOAA/NASA AVHRR Pathfinder program. The main
objective of the Pathfinder program is to reprocess and rehabilitate the long term records
of AVHRR and AVHRR-derived geophysical products from 1981 to the present. As part
of this program, the AVHRR Pathfinder Calibration activity has determined the in-orbit
degradation of the AVHRR visible and near-infrared channels (Rao et al., 1993a). After
applying the appropriate formulae to account for in-orbit degradation, most (if not all)
spurious trends are removed from the long term records of AVHRR and AVHRR-derived
geophysical products. Currently, these formulae exist for the AVHRRs flown on NOAA-
7, NOAA-9 , NOAA-11 and NOAA-14 spacecraft.

Post-launch calibration information for NOAA-7, NOAA-9 and NOAA-11 can be
accessed on the NOAASIS website at URL:
http://www.osdpd.noaa.gov/EBB/noaasis.html or see Appendix G for more information.



                                          3-24         NOAA POD Guide - Jan. 2002 Revision24
4.0            TOVS Level 1b Data

This section describes the TOVS system, which includes three separate sensors: HIRS/2,
MSU and SSU. A fourth sensor, a Solar Backscattered Ultraviolet system (SBUV/2) for
ozone measurement, was added to the instrument complement starting with the NOAA-9
spacecraft. SSB began archiving SBUV data in 1985. Separate documentation entitled:
Solar Backscattered Ultraviolet Radiometer Version 2 (SBUV/2) User's Guide
(November 15, 1990), is available from SSB upon request. Although SBUV/2 data is
available from SSB, there exists no selection software. Therefore, when ordering
SBUV/2 data, the only option is tape-to-tape copies.

Table 4.0-1 lists the instrument parameters for the HIRS/2, MSU, and SSU sensors on the
TIROS-N series. The spectral response of every channel for each TOVS sensor can be
found in Section 1.4 (in each satellite's corresponding subsection).

Section 4.1 describes the HIRS/2 instrument, data characteristics, and the tape formats
available (full copy, unpacked format, and selective extract subsets). Similarly, Sections
4.2 and 4.3 contain specific information about SSU and MSU data, respectively. Section
4.4 contains general information pertaining to the SBUV/2 data, although specific tape
formats are not included. Section 4.5 describes the procedures for calibrating TOVS data
(both visible and thermal).

                   Table 4.0-1. Instrument Parameters for TOVS Sensors.
   TOVS Instrument               HIRS/2                SSU                  MSU
       Parameters
 Calibration              Stable blackbodies   Stable blackbody     Hot reference body
                          (2) and space        and space            and space
                          background                                background each
                                                                    scan cycle
 Cross-track scan angle +/- 49.5               +/- 40.0             +/- 47.35
 (degrees from nadir)
 Scan time (seconds)      6.4                  32.0                 25.6
 Number of steps          56                   8                    11
 Angular FOV              1.25                 10.0                 7.5
 (degrees)
 Step angle (degrees)     1.8                  10                   9.47
 Step time (seconds)      0.1                  4.0                  1.84
 Ground IFOV at nadir     17.4                 147.3                109.3
 (km diameter)
 Ground IFOV at end of 58.5 km cross-track     244 km cross-track x 323.1 km cross-track
 scan                     x 29.9 km along-     186.1 km along-      x 178.8 km along-
                          track                track                track
 Distance between         42.0                 62.3                 168.1
 IFOV centers
 (km along-track)



                                           4-1         NOAA POD Guide - Jan. 2002 Revision1
 Swath width              +/- 1120 km             +/- 737 km               +/- 1174 km
 Data rate                2880                    480                      320
 (bits per second)
 Data precision (bits)    13                      12                       12
 Time between start of    6.4 sec                 32 sec                   25.6 sec
 each scan line
 Step and dwell time      0.1 sec                 4.0 sec                  1.81 sec
 Time *                   0.5 sec                 2.0 sec                  0.9 sec
 * Time- The difference between the start of each scan and the center of the first dwell period.

4.1            HIRS/2 Data

This section describes the instrument, data characteristics, and magnetic tape formats of
the High Resolution Infrared Radiation Sounder/2 (HIRS/2). Section 4.1.1 contains a
description of the instrument and data characteristics. Section 4.1.2 contains the tape
formats for full data set copies, 16-bit unpacked format, and selective extract subsets.

4.1.1                  Instrument Description and Data Characteristics

The HIRS/2 instrument measures incident radiation primarily in the infrared region of the
spectrum including both longwave (15 micrometers) and shortwave (4.3 micrometers)
regions (see Table 4.0-1). The IFOV of the HIRS/2 channels are stepped across the
satellite track by use of a rotating mirror. This cross-track scan, combined with the
satellite's motion in orbit, will provide coverage of a major portion of the Earth's surface.
The width of the crosstrack scan is 99 degrees or 2240 km and consists of 56 steps. The
mirror is stepped from home position in 55 steps of 1.8 degrees. At the end of the scan
(at position 56) the mirror rapidly returns to the home position and repeats the scanning
pattern. Each scan takes 6.4 seconds to complete (100 milliseconds per step) and there
are 42 km between IFOVs along the sub-orbital track. The optical FOV is 1.25 degrees
which gives a ground IFOV of 17.4 km diameter at the nadir. At the end of the scan, the
ground IFOV is 58.5 km cross-track by 29.9 km along-track.

HIRS/2 can be commanded to automatically enter a calibration mode every 256 seconds.
When the instrument is in the calibration mode, the mirror (starting from the beginning of
a scan line) rapidly slews to a space view and samples all channels for the equivalent time
of one complete scan line of 56 scan steps. Next, the mirror is moved to a position where
it views a cold calibration target and data is taken for the equivalent of 56 scan steps.
The mirror is then stepped to view an internal warm target for another 56 scan steps.

Upon completion of the calibration mode, the mirror continues its motion to the home
position where it begins normal Earth scan. The total calibration sequence is equivalent
to three scan lines (no Earth data are obtained during this period). The analog data output
from the HIRS/2 sensor is digitized onboard the satellite at a rate of 2880 bits per second.
At this rate, there are 288 bits per step (step time = 100 milliseconds) which includes all
20 channels. The data is digitized to 13-bits precision.



                                            4-2          NOAA POD Guide - Jan. 2002 Revision2
Table 4.1.1-1 contains typical values of the HIRS/2 spectral characteristics and Noise
Equivalent differential Radiance (NEdN's in units of mW/(m2-sr-cm-1)). There will be
some variation in the parameters from one HIRS/2 instrument to another.

                   Table 4.1.1-1. Typical HIRS/2 Channel Characteristics.
                                Half-power           Maximum Scene
        Channel              Bandwidth (cm-1)       Temperature (K)            Specified NEdN
 1                         3                       280                      3.00
 2                         10                      265                      0.67
 3                         12                      240                      0.50
 4                         16                      250                      0.31
 5                         16                      265                      0.21
 6                         16                      280                      0.24
 7                         16                      290                      0.20
 8                         35                      330                      0.10
 9                         25                      270                      0.15
 10                        60         17*          290          310*        0.16        0.09*
 11                        40                      275                      0.20
 12                        80                      260                      0.19
 13                        23                      300                      0.006
 14                        23                      290                      0.003
 15                        23                      280                      0.004
 16                        23                      260                      0.002
 17                        23         26*          280          350*        0.002
 18                        35                      340                      0.002
 19                        100                     340                      0.001
 20                        1000                    100%A                    0.10%A
 * NOAA-11 and all subsequent satellites (except NOAA-12) have channels 10 and 17 at
 different locations in the spectrum. An * (asterisk) indicates the values for NOAA-11.

4.1.2          Magnetic Tape Formats

The data set format for full data set copies (all channels) is different from the format for
selective extract subsets (selected channels). Sections 4.1.2.1 and 4.1.2.2 contain formats
for HIRS/2 full data set copies and HIRS/2 selective extract subsets, respectively.
Section 4.1.2.1 also includes an explanation of the 16-bit unpacked data format for
HIRS/2 data.

4.1.2.1        Full Data Set Copies

Each HIRS/2 data set normally contains an individual satellite recorder playback in
chronological order. Each record of HIRS/2 data contains the data for one HIRS/2 scan.
Each record is written in binary and contains 4253 bytes in the format contained in Table
4.1.2.1-1.



                                            4-3         NOAA POD Guide - Jan. 2002 Revision3
                        Table 4.1.2.1-1. Format of HIRS/2 Data Record.
             Byte #                        # Bytes                      Content
 1-2                             2                          Scan Line
 3-8                             6                          Time Code
 9-12                            4                          Scan Quality Indicators
 13-16                           4                          Earth Location Delta
 17-736                          720                        Calibration Coefficients
 737-740                         4                          Height and Local Zenith Angle
 741-964                         224                        Earth Location
 965-3780                        2816                       HIRS/2 Data
 3781-3844                       64                         Minor Frame Quality
 3845-4253                       409                        Spare

The scan line number is from 1 to n. In the case of data gaps which cover one or more
complete scans, the scan line number will be incremented to compensate for the data gap.

The time code consists of the year, Julian day, and UTC time of day in milliseconds.
The year is contained in the first 7 bits of the first two bytes, the 9-bit day of year is right-
justified in the first two bytes and the 27-bit millisecond UTC time of day is right-
justified in the last four bytes. All other bits are zero. The time code has the same format
for all Level 1b data sets.

The scan quality information is contained in four bytes. The first two bytes contain
processing detected conditions, the third byte contains DACS quality indicators, and the
last byte is spare. The scan quality indicators contain a summary of the quality of the 64
TIP minor frames which make up a HIRS/2 scan. The quality bytes are defined in Table
4.1.2.1-2.


              Table 4.1.2.1-2. Format of the HIRS/2 Scan Quality Information.
 Byte     Bit                                     Definition
 9       7      FATAL FLAG - Data should not be used for product generation.
         6      TIME ERROR - A time sequence error was detected while processing this
                scan.
         5      DATA GAP - A data gap of one or more scans precedes this scan.
         4      DWELL - Data gap was due to dwell mode condition.
         3      DATA FILL - The scan contains partial data fill due to a data gap of less than
                one scan. Each halfword of data fill is set to hex 7FFF.
         2      DACS ERROR - This scan contains data that is suspect due to DACS QC
                error(s).
         0-1    SCAN TYPE - The type of data found in this scan line (01=space calibration
                view, 10=cold BB view, 11=main BB view, and 00=normal Earth view)
 10      7      MIRROR LOCKED - The mirror was in a locked position during this scan.
                Normal Earth scanning was disrupted.
         6      MIRROR POSITION ERROR - A scan mirror sequence error was detected


                                              4-4          NOAA POD Guide - Jan. 2002 Revision4
                during this scan.
         5      MIRROR REPOSITION - This scan was used to reposition the mirror.
         4      FILTER SYNC - Improper filter synchronization during this scan.
         3      SCAN PATTERN ERROR - HIRS/2 line counter not incrementing properly.
         2      CALIBRATION - Insufficient data collected to calibrate this scan. If
                calibration coefficients are available, they will be the old coefficients.
         1      NO EARTH LOCATION DATA - Earth location data was not available.
         0      EARTH LOCATION DELTA - Predicted less actual time exceeds tolerance of
                3 seconds.
 11      7      BIT SYNC STATUS - Drop lock during this scan. The scan line is suspect.
         6      SYNC ERROR - Frame sync word error greater than zero during this scan.
         5      FRAME SYNC LOCK - Frame sync lock during this scan.
         4      FLYWHEELING - Flywheeling detected during this scan. The scan line is
                suspect.
         3      BIT SLIPPAGE - Bit slippage detected during this scan. The scan line is
                suspect.
         2      TIP PARITY - DACS TIP parity detected during this scan. The scan line is
                suspect.
         1      AUXILIARY FRAME SYNC ERRORS - The number of bit errors in auxiliary
                frame sync was non-zero during this scan.
         0      SPARE
 12      7-4    MAJOR FRAME COUNTER
         3-0    SCAN SEQUENCE COUNTER - Number (0-4) of scan position within the
                32-second cycle.

The Earth location delta is the time difference between the scan time code and the time
code associated with the Earth location data appended to this record. The value is in
milliseconds and is right-justified in the four bytes.

The twenty HIRS/2 channels occur in the Level 1b data record in the following order: 1,
17, 2, 3, 13, 4, 18, 11, 19, 7, 8, 20, 10, 14, 6, 5, 15, 12, 16, and 9.

The HIRS/2 calibration coefficients are contained in three groups. The first group of
240 bytes contains the three manually calibrated coefficients for each of the 20 channels
stored in descending order. The second group of 240 bytes contain the three auto-
calibrated coefficients for each of the 20 channels stored in descending order. The third
group of 240 bytes contains the normalization coefficients by channel used in auto
calibration stored in ascending order. Each value is stored in four bytes and contains a
scaled number of fractional bits. The scaling factor for the coefficients in ascending
order is 222, 230 and 244, respectively, and fields for non-computed values are set to zero.
The order of the coefficients is shown in Table 4.1.2.1-3.

              Table 4.1.2.1-3. Order of the HIRS/2 calibration coefficients.
 Channel 1 manual coefficient 1 (2nd order term)
 Channel 1 manual coefficient 2 (1st order term)


                                             4-5         NOAA POD Guide - Jan. 2002 Revision5
 Channel 1 manual coefficient 3 (0th order term)
 Channel 17 manual coefficient 1 (2nd order term)
 ...
 Channel 1 auto coefficient 1 (2nd order term)
 Channel 1 auto coefficient 2 (1st order term)
 Channel 1 auto coefficient 3 (0th order term)
 Channel 17 auto coefficient 1 (2nd order term)
 ...
 Channel 1 normalization coefficient 1 (0th order term)
 Channel 1 normalization coefficient 2 (1st order term)
 Channel 1 normalization coefficient 3 (2nd order term)
 Channel 17 normalization coefficient 1 (0th order term)
 ...

The sets of coefficients for the HIRS/2 channels are present in the same sequence in
which the channels are present in the data record (ascending/descending refers to
sequence of the three terms of each coefficient).

Calibration intercepts whose absolute values exceed 512 are truncated when they are
scaled and inserted into the Level 1b database by the program DEFERT. For most
channels of most TIROS-N series satellites instruments, this presents no problem because
the absolute values of their intercepts are less than 512. However, Channels 1 and 2 of
the NOAA-12 HIRS/2 and Channel 1 of the HIRS/2 instruments on NOAA-6, -7, -8, -10,
-11, -13 and -14 are exceptions. In these channels, the absolute values of the intercepts
exceed 512, and the scaled intercept values in the Level 1b database are truncated.
Consequently, the intercepts for these channels are incorrect when they are descaled by
users of the Level 1b data. Users may recover the correct values by adjusting the
descaled values using the following procedures:

       NOAA-12 Channel 1:

       If the absolute value of the descaled intercept is less than 200, increase the
       absolute value by 2048 (and maintain the original sign). For example, if the
       descaled intercept is -11, the correct intercept is -2059.

       If the absolute value of the descaled intercept is greater than or equal to 200,
       increase the absolute value by 1536 (and maintain the original sign). For
       example, if the descaled intercept is -511, the correct intercept is -2047.

       NOAA-12 Channel 2;
       and NOAA-6, -7, -8, -10, -11, -13 and -14 Channel 1:

       If the absolute value of the descaled intercept is less than 200, increase the
       absolute value by 512 (and maintain the original sign). For example, if the
       descaled intercept is -38, the correct intercept is -550; if the descaled intercept is
       95, the correct intercept is 607.


                                            4-6         NOAA POD Guide - Jan. 2002 Revision6
       If the absolute value of the descaled intercept is greater than or equal to 200, make
       no adjustment.

Also note that the HIRS/2 instrument can have negative numbers for the calibration
coefficients. The HIRS/2 auto coefficient 2 will be negative for all channels except
Channel 20. Typical values for auto coefficient 2 range from -0.5 for Channel 1 to-0.5 x
10-3 for Channel 19. The auto coefficient 3 can be positive or negative depending on the
channel. Values usually range from several hundred for Channel 1 to 1 for Channel 19.

See Section 4.5 on how to use the HIRS/2 calibration coefficients.

The height and Local Zenith Angle of the scan is contained in four bytes. The height is
stored in the first two bytes in kilometers. The Local Zenith Angle is stored in the last
two bytes in 128ths of a degree. The Local Zenith Angle is the angle from the observed
point on the earth to the satellite as measured from the local vertical. The Local Zenith
Angle given here is for the fields of view at the edge of scan. The Earth location data
consists of latitude and longitude pairs for each of the 56 field of views (FOV) in the
scan. The latitude and longitude values are stored in two-byte fields in 128ths of a
degree. The order of the data is: FOV 1 latitude, FOV 1 longitude, FOV 2 latitude, FOV
2 longitude, etc.

Each TIP minor frame contains 286 bits of HIRS/2 data packed into 36 bytes. The 286
bits are made up of 22 13-bit words. The 22 13-bit words will be repacked into 44 bytes
according to the following scheme.

       (a) The first two 13-bit words will be packed left-justified into the first four bytes
       of the 44-byte group. The least significant six bits of the four bytes will be zero
       filled. These two words describe the encoder position, electronic calibration
       level, Channel 1 period monitor, element number, and filter sync designator.

       (b) The last 20 13-bit words will be repacked into 20 halfwords (right justified).
       These 13-bit words consist of a sign bit (MSB) and the 12 remaining bits
       represent the radiant signal output for the 20 HIRS/2 channels for the first 56
       minor frames. If the sign bit is zero, then the radiant signal is negative (cooler
       than the filter wheel); if the sign bit is one, then the radiant signal is positive
       (warmer than the filter wheel). Minor frames 56-63 also contain these 20 words as
       described in Table 4.1.2.1-4.

The 44-byte group will be packed sequentially in the scan record. The content of the 286
bits found in each of the 64 TIP minor frames within the HIRS/2 scan is found in Table
4.1.2.1-4.

              Table 4.1.2.1-4. Format of TIP HIRS/2 data output for one scan.
           Bit #                                   Description
                                    Minor Frames 0-55


                                            4-7         NOAA POD Guide - Jan. 2002 Revision7
285-278   Encoder Position (1-56=Earth view, 68=space, 105=cold BB,
          156=warm BB)
277-273   Electronic Calibration Level (0-31, any level indicates both + and -
          )
272-267   Channel 1 Period Monitor
266-261   Element Number (one less than encoder value for Earth views)
260       Filter Sync Designator (out of sync=0)
259-0     Radiant signal Output (20 channels x 13 bits)
                    Minor Frames 55-63
285-260   Same as above
                      Minor Frame 56
259-0     Positive Electronic Calibration (calibration level advanced one of
          32 equal levels on succeeding scans)
                      Minor Frame 57
259-0     Negative Electronic Calibration
              Minor Frame 58 (Thermistors)
259-195   Internal Warm Target #1, 5 times (independent samples, counts)
194-130   Internal Warm Target #2, 5 times (independent samples, counts)
129-65    Internal Warm Target #3, 5 times (independent samples, counts)
64-0      Internal Warm Target #4, 5 times (independent samples, counts)
              Minor Frame 59 (Thermistors)
259-195   Internal Cold Target #1, 5 times
194-130   Internal Cold Target #2, 5 times
129-65    Internal Cold Target #3, 5 times
64-0      Internal Cold Target #4, 5 times
              Minor Frame 60 (Thermistors)
259-195   Filter Housing Temperature #1, 5 times
194-130   Filter Housing Temperature #2, 5 times
129-65    Filter Housing Temperature #3, 5 times
64-0      Filter Housing Temperature #4, 5 times
                      Minor Frame 61
259-195   Patch Temperature Expanded, 5 times
194-130   First State Temperature, 5 times
129-65    Filter Housing Control Current, 5 times
          Electronic Calibration DAC, 5 times (expected count for electronic
64-0      calibration)
                      Minor Frame 62
259-247   Scan Mirror Temperature
246-234   Primary Telescope Temperature
233-221   Secondary Telescope Temperature
220-208   Baseplate Temperature
207-195   Electronics Temperature
194-182   Patch Temperature
181-169   Scan Motor Temperature


                         4-8        NOAA POD Guide - Jan. 2002 Revision8
 168-156                    Filter Motor Temperature
 155-143                    0 Volts to ADC
 142-130                    Patch Control Power
 129-117                    Scan Motor Current
 116-104                    Filter Motor Current
 103-91                     +15 VDC
 90-78                      -15 VDC
 77-65                      +7.5 VDC
 64-52                      -7.5 VDC
 51-39                      +10 VDC
 38-26                      +5.0 VDC TLM
 25-13                      Analog Ground
 12-0                       Analog Ground
                                        Minor Frame 63
 259-247                    HIRS/2 Line Count
 246-245                    Zero Fill
 244-242                    Serial Number
 241-234                    Command Status
 233-229                    Fill Zeroes
 228-221                    Command Status
                            Binary Code                                    Decimal Code
 220-208                    (1,1,1,1,1,0,0,1,0,0,0,1,1)                    +3875
 207-195                    (...)                                          +1443
 194-182                    (...)                                          -1552
 181-169                    (...)                                          -1882
 168-156                    (...)                                          -1631
 155-143                    (...)                                          -1141
 142-132                    (...)                                          -1125
 131-117                    (...)                                          -3655
 116-104                    (...)                                          -2886
 103-91                     (...)                                          -3044
 90-78                      (...)                                          -3764
 77-65                      (...)                                          -3262
 64-52                      (...)                                          -2283
 51-39                      (...)                                          -2251
 38-26                      (...)                                          +3214
 25-13                      (...)                                          +1676
 12-0                       (...)                                          +1992

The 64 bytes of the minor frame quality field contains data quality information for each
of the 64 minor frames making up a scan line. The format for each byte is contained in
Table 4.1.2.1-5.

                 Table 4.1.2.1-5. HIRS/2 minor frame quality field format.


                                          4-9         NOAA POD Guide - Jan. 2002 Revision9
     Bit                                     Description
 7         TIME ERROR - This 44-byte group contains data that is suspect due to a time error.
 6         MISSING DATA - This 44-byte group contains data fill due to a data gap.
 5         DWELL DATA - This 44-byte group contains data fill due to a TIP dwell condition.
 4         DACS - This 44-byte group contains data that is suspect due to DACS QC error(s)
           (DROP LOCK, SYNC ERROR, FLYWHEEL, BIT SLIP, TIP PARITY).
 3         MIRROR LOCKED - The mirror was determined as locked during this minor
           frame.
 2         MIRROR POSITION ERROR - A scan mirror sequencing error was detected
           during this minor frame.
 1         SLEW INDICATOR - The mirror was moving during this minor frame. This
           includes normal movement (e.g., moving between targets).
 0         PARITY BIT - Minor word parity bit (odd parity). This is not an error indicator.

The 16-bit unpacked data format for full copy HIRS/2 data has the same format as the
"packed" data described above except for the format of the HIRS/2 channel data. Also,
the minor frame quality has the same format as described above but it starts on the first
halfword (16 bits) boundary following the end of the HIRS/2 channel data.

The channel data itself (contained in halfwords 3-22 when all channels are requested)
will be packed in consecutive halfwords for TIP minor frames 0-55. The other eight
minor frames (56-63) still retain their 44-byte format. The unpacked data format for full
copy HIRS/2 data is shown in Table 4.1.2.1-6. Note that the order of the channels is the
same as for the packed format in Section 4.1.2.1. The record for the HIRS/2 full copy
unpacked data format contains 3620 bytes.

            Table 4.1.2.1-6. Format for unpacked full copy HIRS/2 data.
 Minor Frame #      Byte #           Bit #                     Content
 0-55           1-2             15-13           Zero filled
                                12-0            Channel 1 data value
                3-4             15-13           Zero filled
                                12-0            Channel 17 data value
                5-6             15-13           Zero filled
                                12-0            Channel 2 data value
                ...             ...             ...
                39-40           15-13           Zero filled
                                12-0            Channel 9 data value
 56-63          ...             285-0           See Table 4.1.2.1-4 for bit description

4.1.2.2        Selective Extract Subsets

When channels are selected for HIRS/2 data, the format is like that described in Section
4.1.2.1, except that the format of the HIRS/2 channel data changes. Also, the minor
frame quality has the same format described in Section 4.1.2.1 but it starts on the first



                                          4-10        NOAA POD Guide - Jan. 2002 Revision10
halfword (16 bits, half of a 32-bit word) boundary following the end of the HIRS/2
channel data.

The channel data itself (contained in halfwords 3-22 when all channels are requested)
will be packed in consecutive halfwords for TIP minor frames 0-55 (corresponding to the
56 FOVs per scan). The other eight minor frames (56-63) will still retain their 44-byte
format. Note: The channels will be in ascending order when packed into the record.
Table 4.1.2.2-1 shows the structure of the HIRS channel data when two channels (1 and
2) are selected.

       Table 4.1.2.2-1. Format of the HIRS/2 channel data for two-channel select.
     Minor Frame #                 Bit #                         Content
 0-55                    31-29                   Zero Filled
                         28-16                   Channel 1 Data Value
                         15-13                   Zero Filled
                         12-0                    Channel 2 Data Value
 56-63                   285-0                   See Table 4.1.2.1-4 for bit description

4.2            SSU Data

This section describes the Stratospheric Sounding Unit (SSU), its data characteristics, and
magnetic tape formats. Section 4.2.1 contains a description of the SSU instrument and its
data characteristics. Section 4.2.2 contains the tape formats for full data set copies, 16-bit
unpacked format, and selective extract subsets.

4.2.1          Instrument Description and Data Characteristics

The SSU is a step-scanned far-infrared spectrometer with three channels in the 15
micrometer carbon dioxide absorption band (the SSU instruments have been contributed
to the TIROS-N series satellites by the British government). It makes use of the pressure
modulation technique to measure radiation emitted from carbon dioxide at the top of the
Earth's atmosphere. The principles of operation are based on the selective chopper
radiometer flown on Nimbus 4 and 5, and the pressure modulator radiometer flown on
Nimbus 6. The three SSU channels have the same frequency, but different cell pressures,
as shown in Table 4.2.1-1.

                    Table 4.2.1-1. Cell pressures of the SSU channels.
 Channel # Central Wave #             Cell        Pressure of Weighting          Typical NEdN*
                  (cm-1)           Pressure         Function Peak (mb)
                                     (mb)
 1          668                 100               15                            0.30
 2          668                 35                5                             0.40
 3          668                 10                1.5                           1.00
 * NEdN is Noise Equivalent differential radiance (mW/(m2-sr-cm-1))




                                           4-11         NOAA POD Guide - Jan. 2002 Revision11
The SSU consists of a single primary telescope with a 10 degree IFOV which is step-
scanned perpendicular to the satellite subpoint track. Each scan line is composed of eight
individual 4.0 second steps and requires a total of 32 seconds, including time for the
mirror retrace. The 10 degree IFOV gives a resolution of 147 km at the satellite subpoint
and the stepping produces an underlap between adjacent scan lines of approximately 62
km at nadir. A calibration sequence is initiated every 256 seconds (8 scans) during which
the radiometer is in turn, stepped to a position to view unobstructed space and an internal
blackbody at a known temperature. This calibration mode is synchronized with the
HIRS/2 instrument.

Data is sampled at the rate of 40 samples per second, and is digitized to 12-bit precision.
Therefore, the SSU data rate is 480 bits per second.

4.2.2          Magnetic Tape Formats

The data set format for full data set copies (all channels) is different from the format for
selective extract subsets (selected channels). Sections 4.2.2.1 and 4.2.2.2 contain formats
for SSU full data set copies and SSU selective extract subsets, respectively. Section
4.2.2.1 also includes the unpacked format for SSU data.

4.2.2.1        Full Data Set Copies

Each SSU data set normally contains an individual satellite recorder playback. Data
within each SSU data set are in chronological order with one record for each SSU scan.
Each record is written in binary and contains 2498 bytes in the format as shown in Table
4.2.2.1-1.

                             Table 4.2.2.1-1. Format of SSU data.
             Byte #                        # Bytes                        Content
 1-2                             2                           Identifier Field
 3-4                             2                           Scan Line
 5-10                            6                           Time Code
 11-14                           4                           Scan Quality Indicator
 15-16                           2                           Earth Location Delta
 17-112                          96                          Calibration Coefficients
 113-116                         4                           Height and Local Zenith Angle
 117-148                         32                          Earth Location Data
 149-2068                        1920                        SSU Data
 2069-2100                       32                          Scan Position Quality
 2101-2498                       398                         Spare

The identifier field contains the Spacecraft ID in the first byte (see Spacecraft ID in
Section 2.0.1) and the SSU data set code in the second byte. The SSU data set code is
always the number 7.




                                          4-12         NOAA POD Guide - Jan. 2002 Revision12
The scan line, time code, and height and Local Zenith Angle fields have the same
format as the HIRS/2 data in Section 4.1.2.1.

The scan quality information is contained in four bytes. The first two bytes contain
processing detected conditions, the third byte contains DACS quality indicators, and the
last byte is spare. The scan quality indicators contain a summary of the quality of the 320
TIP minor frames which make up an SSU scan. The definition of the quality bytes is
contained in Table 4.2.2.1-2.

                   Table 4.2.2.1-2. Format of the SSU scan quality information.
 Byte        Bit                                       Definition
 1       7          FATAL FLAG - Data should not be used for product generation.
         6          DATA GAP - A data gap of one or more scans precedes this scan.
         5          DATA FILL - The scan contains partial data fill. Each halfword of data fill
                    is set to hex AFFFF@.
         4          DWELL - Data gap was due to dwell data.
         3          TIME ERROR - This scan contains data that is suspect due to time error(s).
         2          DACS - This scan contains data that is suspect due to DACS QC.
         1          NO EARTH LOCATION - Earth location data not available.
         0          EARTH LOCATION DELTA - Predicted less actual time exceeds tolerance
                    of 3 seconds.
 2       7          CALIBRATION - Insufficient data was collected to calibrate this scan, for at
                    least one channel. On TIROS-N, Channel 3 was not working properly and
                    this bit is set quite often. However, calibration data for the other two
                    channels is current.
         6          SPACE VIEW - This scan contains space view data.
         5          BLACKBODY VIEW - This scan contains blackbody view data.
         4          MIRROR LOCKED - The mirror was in a locked position during this scan.
                    Normal Earth scanning was disrupted.
         3          SCAN SEQUENCE - A scan mirror sequence error was detected during this
                    scan.
         2          MIRROR SYNC - Mirror sync was lost during this scan. Normal Earth
                    scanning was disrupted.
         1          LINEARITY - ADC non-linearity was detected during this scan. Usually not
                    an error unless detected continuously.
         0          SPARE
 3       7          BIT SYNC STATUS - Drop lock during this scan. The scan line is suspect.
         6          SYNC ERROR - Number of bit errors in frame sync was non-zero during
                    this scan. The scan line is suspect.
         5          FRAME SYNC LOCK - Frame sync lock during this scan.
         4          FLYWHEELING - Flywheeling detected during this scan. The scan line is
                    suspect.
         3          BIT SLIPPAGE - Bit slippage detected during this scan. The scan line is
                    suspect.
         2          TIP PARITY - DACS TIP parity detected during this scan. The scan line is


                                           4-13        NOAA POD Guide - Jan. 2002 Revision13
                   suspect.
          1        AUXILIARY FRAME SYNC ERRORS - The number of bit errors in
                   auxiliary frame sync was non-zero during this scan. The scan line is suspect.
          0        SPARE
 4        7-4      MAJOR TIP FRAME (0-7) from which this scan was generated.
          3-0      SPARE

The Earth location delta contains the time difference between the scan time code and
the time code associated with the Earth location data appended to this record. The value
is right-justified in the two bytes and is in milliseconds.

The calibration coefficients for SSU data contain three groups. Each group contains
coefficients for all three channels. The first group of 24 bytes contains the manual
calibration slope and intercept coefficients. The second group of 24 bytes contains the
auto calibration slope and intercept coefficients. The third group of 48 bytes contains the
normalization coefficients, stored in ascending order. Each value is stored in four bytes
and contains a scaled number of fractional bits. The scaling factor for the lowest order
coefficients, the constants, is 222 , with increasing order coefficients scaled by 230, 244 and
256, respectively. All fields for non-computed values are set to zero. The coefficients
are stored as shown in Table 4.2.2.1-3.

                    Table 4.2.2.1-3. Storage of SSU calibration coefficients.
                               Channel 1 manual slope coefficient
                             Channel 1 manual intercept coefficient
                               Channel 2 manual slope coefficient
                                                ...
                                 Channel 1 auto slope coefficient
                                  Channel 1 intercept coefficient
                                 Channel 2 auto slope coefficient
                                                ...
                      Channel 1 normalization coefficient 1 (0th order term)
                      Channel 1 normalization coefficient 2 (1st order term)
                     Channel 1 normalization coefficient 3 (2nd order term)
                     Channel 1 normalization coefficient 4 (3rd order term)
                      Channel 2 normalization coefficient 1 (0th order term)
                                                ...

See Section 4.5 on how to use the SSU calibration coefficients. The Earth location field
contains the latitude and longitude for each of the 8 Earth FOVs in the scan. The latitude
and longitude values are stored in the two-byte fields in 128ths of a degree. The Earth
location data is ordered as follows: FOV 1 latitude, FOV 1 longitude, FOV 2 latitude,
FOV 2 longitude, etc.

Each TIP minor frame contains six bytes (3 two-byte pairs) of SSU data. The data is
organized into 60-byte groups (10 TIP minor frames) and placed in the SSU Level 1b


                                           4-14          NOAA POD Guide - Jan. 2002 Revision14
data set. Each 60-byte group contains data for one-fourth of an SSU FOV so that each
SSU data set record contains 32 of the 60-byte groups. The order of the data in each 60-
byte group is defined in Table 4.2.2.1-4.

                Table 4.2.2.1-4. Format of each 60-byte group of SSU data.
               SSU Data                          Bytes               Tip Minor Frame
 Digital Word 1                        1,2                        1
 Digital Word 2                        3,4
 Digital Word 3                        5,6
 Space Port Temperature                7,8                        2
 Earth Port Temperature                9,10
 PMC Bulkhead Temperature              11,12
 Detector Temperature                  13,14                      3
 Blackbody Temperature (Space Side)    15,16
 Blackbody Temperature (Sun Side)      17,18
 Cell Temperature Channel 1            19,20                      4
 Cell Temperature Channel 2            21,22
 Cell Temperature Channel 3            23,24
 Base Plate Temperature                25,26                      5
 Middle Bulkhead Temperature           27,28
 Optics Baseplate Temperature          29,30
 Signal Output Channel 1               31,32                      6
 Signal Output Channel 2               33,34
 Signal Output Channel 3               35,36
 Thermistor Reference                  37,38                      7
 Mirror Fine Position                  39,40
 Blackbody Temperature (Point)         41,42
 PMC Amplitude Channel 1               43,44                      8
 PMC Amplitude Channel 2               45,46
 PMC Amplitude Channel 3               47,48
 ADC Calibration 5% of Full Scale      49,50                      9
 ADC Calibration 50% of Full Scale     51,52
 ADC Calibration 90% of Full Scale     53,54
 Signal Output Channel 1               55,56                      10
 Signal Output Channel 2               57,58
 Signal Output Channel 3               59,60

The scan position quality is contained in 32 bytes, one byte for each 60-byte group of
SSU data. The definition of the quality byte is contained in Table 4.2.2.1-5.

            Table 4.2.2.1-5. Definition of the scan position quality for SSU data.

 Byte    Bit                                 Definition
 1      1       TIME ERROR - This 30-word group contains data that is suspect due to a time


                                         4-15        NOAA POD Guide - Jan. 2002 Revision15
                 error.
          2      MISSING DATA - This 30-word group contains data fill due to a data gap.
          5      DWELL - This 30-word group contains data fill due to a dwell condition.
          4      DACS - This 30-word group contains data that is suspect due to DACS QC
                 error(s) (DROP LOCK, SYNC ERROR, FLYWHEEL, BIT SLIP, TIP
                 PARITY).
          5      SCAN SEQUENCE ERROR - A scan mirror position sequence error was
                 detected for this 30-word block.
          6      MIRROR SYNC ERROR - The mirror sync was lost during this 30-word
                 block.
          7-8    SPARE

The unpacked format for a full copy SSU data set is very similar to the "packed" format
described above except for the field containing the SSU data. The signal output for each
selected channel (contained in TIP minor frames 6 and 10) is substituted for the complete
SSU data field. The unpacked full copy SSU data field has the format shown in Table
4.2.2.1-6. Note: the 400 spare bytes have been eliminated, so the unpacked full copy
SSU data record contains only 564 bytes.

                   Table 4.2.2.1-6. Format of unpacked full copy SSU data.
      Byte #             # Bytes                             Content
 149-150             2               Signal Output Channel 1, Group 1, TIP Minor Frame 6
 151-152             2               Signal Output Channel 2, Group 1, TIP Minor Frame 6
 153-154             2               Signal Output Channel 3, Group 1, TIP Minor Frame 6
 155-156             2               Signal Output Channel 1, Group 1, TIP Minor Frame 10
 157-158             2               Signal Output Channel 2, Group 1, TIP Minor Frame 10
 159-160             2               Signal Output Channel 3, Group 1, TIP Minor Frame 10
 161-162             2               Signal Output Channel 1, Group 2, TIP Minor Frame 6
 ...                 ...             ...
 527-528             2               Signal Output Channel 1, Group 32, TIP Minor Frame 10
 529-530             2               Signal Output Channel 2, Group 32, TIP Minor Frame 10
 531-532             2               Signal Output Channel 3, Group 32, TIP Minor Frame 10
 533-564             32              Scan position quality

4.2.2.2         Selective Extract Subsets

When channels are selected for SSU data sets, the format of the SSU data is the only field
that changes from the format described in Section 4.2.2.1. The signal output for each
selected
channel (contained in TIP minor frames 6 and 10) is substituted for the complete SSU
data field. One or two channels can be selected for the SSU data sets. If Channels 2 and
3 were selected, the SSU data field would have the format shown in Table 4.2.2.2-1.
Immediately following the SSU data values, the scan position quality is written starting
on the next halfword boundary.



                                         4-16         NOAA POD Guide - Jan. 2002 Revision16
      Table 4.2.2.2-1. Format of SSU data field when Channels 2 and 3 are selected.
      Byte #            # Bytes                          Content
 149-150            2             Signal Output Channel 2, Group 1, TIP Minor Frame 6
 151-152            2             Signal Output Channel 3, Group 1, TIP Minor Frame 6
 153-154            2             Signal Output Channel 2, Group 1, TIP Minor Frame 10
 155-156            2             Signal Output Channel 3, Group 1, TIP Minor Frame 10
 157-158            2             Signal Output Channel 2, Group 2, TIP Minor Frame 6
 ...                ...           ...
 397-398            2             Signal Output Channel 2, Group 32, TIP Minor Frame 6
 399-400            2             Signal Output Channel 3, Group 32, TIP Minor Frame 6
 401-402            2             Signal Output Channel 2, Group 32, TIP Minor Frame 10
 403-404            2             Signal Output Channel 3, Group 32, TIP Minor Frame 10

4.3            MSU Data

This section describes the Microwave Sounding Unit (MSU), its data characteristics, and
magnetic tape formats. Section 4.3.1 contains a description of the instrument and its data
characteristics. Section 4.3.2 describes the tape formats for full data set copies, 16-bit
unpacked format, and selective extract subsets.

4.3.1                 Instrument Description and Data Characteristics

MSU is a passive scanning microwave spectrometer with four channels in the 5.5
micrometer oxygen region. The four channels respond to the following respective
spectral frequencies: 50.3, 53.74, 54.96, and 57.95 GHz with a channel bandwidth of 200
MHz in each case, and a typical NEdT of 0.3 K. The MSU sensors consist of two four-
inch diameter antennas, each having an IFOV of 7.5 degrees. The antennas are step-
scanned through eleven individual 1.84-second Earth viewing steps and require a total of
25.6 seconds to complete. The 124 km IFOV resolution at the subpoint creates an
underlap of approximately 115 km between adjacent scan lines. See Table 4.0-1.

The MSU data output represents an apparent brightness temperature after a 1.84-second
integration period per step. The data is quantized to 12-bit precision and combined with
telemetry and step position information to produce an effective output data rate of 320
bits per second.

Unlike the HIRS/2 and SSU instruments, the MSU has no special calibration sequence
that interrupts normal scanning. The calibration data is included in a scan line of data.
From the last Earth view position, the reflector rapidly moves 4 steps to view space, 10
additional steps to view the housing, and then returns to the home position to begin
another scan line. Since each scan line requires 25.6 seconds, synchronization of MSU
within the other two TOVS instruments occurs every 128 seconds (5 scan lines).

4.3.2                 Magnetic Tape Formats




                                          4-17         NOAA POD Guide - Jan. 2002 Revision17
The data set format for full data set copies (all channels) is different from the format for
selective extract subsets (selected channels). Sections 4.3.2.1 and 4.3.2.2 contain formats
for MSU full data set copies and MSU selective extract subsets, respectively. Section
4.3.2.1 also includes the unpacked format for MSU data (all channels).

4.3.2.1              Full Data Set Copies

Each MSU data set normally contains an individual satellite recorder playback. Data
within each MSU data set are in chronological order with one record for each MSU scan.
Each record is written in binary and contains 437 bytes. Table 4.3.2.1-1 contains the
format for the MSU data.

                                 Table 4.3.2.1-1. Format of MSU Data.
                Byte #                          # Bytes                     Content
 1-2                                 2                          Scan Line
 3-8                                 6                          Time Code
 9-12                                4                          Scan Quality Indicators
 13-16                               4                          Earth Location Delta
 17-112                              96                         Calibration Coefficients
 113-116                             4                          Height and Local Zenith Angle
 117-160                             44                         Earth Location Data
 161-384                             224                        MSU Data
 385-400                             16                         Scan Position Quality
 401-437                             37                         Spare

The scan line, time code, and height and Local Zenith Angle fields have the same
format as the HIRS/2 data in Section 4.1.2.

The scan quality information is stored in four bytes. The first two bytes contain
processing detected conditions, the third byte contains DACS quality indicators, and the
last byte is spare. The scan quality indicators contain a summary of the quality of the 256
TIP minor frames which make up a MSU scan. The definition of the quality bytes is
contained in Table 4.3.2.1-2.

                         Table 4.3.2.1-2. Format of the MSU scan quality bytes.
 Byte          Bit                                         Definition
 9         7            FATAL FLAG - Data should not be used for product generation.
           6            DATA GAP - A data gap of one or more scans precedes this scan.
           5            DATA FILL - This scan contains partial data fill due to missing data. Each
                        halfword of fill is set to hex A7FFF@.
           4            DWELL - Data gap and/or data fill was due to dwell data.
           3            TIME ERROR - This scan contains data that is suspect due to time error(s).
           2            DACS - This scan contains data that is suspect due to DACS QC.
           1            NO EARTH LOCATION - Earth location data not available.
           0            EARTH LOCATION DELTA - Predicted less actual time exceeds tolerance


                                              4-18        NOAA POD Guide - Jan. 2002 Revision18
                  of 3 seconds.
 10       7       CALIBRATION - Insufficient data was collected to calibrate this scan, for at
                  least one channel. If calibration coefficients are available, they will be old
                  coefficients.
          6-5     SPARE
          4       SCAN DISABLE - The scan disable condition was detected during this scan.
                  Normal Earth scanning was disrupted. Scan line is suspect.
          3       SCAN SEQUENCE - A scan mirror sequence error was detected during this
                  scan.
          2       MIRROR SEQUENCE - A mirror sequence error was detected during this
                  scan.
          1-0     SPARE
 11       7       BIT SYNC STATUS - Drop lock during this scan. Scan line is suspect.
          6       SYNC ERROR - Frame sync word error greater than zero during this scan.
          5       FRAME SYNC LOCK - Frame sync lock during this scan.
          4       FLYWHEELING - Flywheeling detected during this scan.
          3       BIT SLIPPAGE - Bit slippage detected during this scan.
          2       TIP PARITY - DACS TIP parity detected during this scan.
          1       AUXILIARY FRAME SYNC ERRORS - The number of bit errors in
                  auxiliary frame sync was non-zero during this scan.
          0       SPARE
 12       7-4     MAJOR FRAME COUNTER
          3-0     SCAN SEQUENCE COUNTER - Number (0-4) of scan position within the
                  128-second cycle.

The Earth location delta field contains the time differences between the scan time code
and the time code associated with Earth location data appended to this record. The value,
in milliseconds, is right-justified in the four bytes.

The calibration coefficient field contains two groups of calibration coefficients. Each
group contains coefficients for all four channels. The first group of 32-bytes contains the
calibration slope and intercept coefficients stored in ascending order. Each value is
stored in four bytes and contains a scaled number of fractional bits. The scaling factor
for the lowest order coefficients, the constants, is 222, with increasing order coefficients
scaled by 230, 244 and 256, respectively. See Section 4.5 on how to use MSU calibration
coefficients. The coefficients for MSU are stored as shown in Table 4.3.2.1-3.

                   Table 4.3.2.1-3. Order of MSU calibration coefficients.
 Channel 1 slope coefficient (1st order term)
 Channel 1 intercept coefficient (0th order term)
 Channel 2 slope coefficient (1st order term)
 ...
 Channel 1 normalization coefficient 1 (0th order term)
 Channel 1 normalization coefficient 2 (1st order term)
 Channel 1 normalization coefficient 3 (2nd order term)


                                          4-19         NOAA POD Guide - Jan. 2002 Revision19
            Channel 1 normalization coefficient 4 (3rd order term)
            Channel 2 normalization coefficient 1 (0th order term)
            ...

           The Earth location field contains the latitude and longitude for each of the 11 Earth
           FOVs in the scan. The latitude and longitude values are stored in two-byte fields in
           128ths of a degree. The order of this data is: FOV 1 latitude, FOV 1 longitude, FOV 2
           latitude, FOV 2 longitude, etc.

           The MSU data is extracted from the TIP frames (256 TIP minor frames per MSU scan),
           all zero words are discarded, and the meaningful 224 bytes (112 halfword groups) are
           organized by scan position and placed in the Level 1b MSU data set as shown in Table
           4.3.2.1-4.

                                      Table 4.3.2.1-4. Format of MSU data.
                  TELEMETRY                                             EARTH VIEW
                                                       Channel   Channel   Channel    Channel
    Scan   Instrument    Instrument      Instrument        1         2         3          4       Scan Position
    Spot     Voltages   Temperature     Temperature      Data      Data      Data       Data      Line Count (2)
           INSTR.                                      CH.1      CH.2      CH. 3      CH. 4
           SER. #       T1 CAL LO      T2 CAL LO       DATA      DATA      DATA       DATA      SCAN POS 0
1           [0]         [1]            [2]             [3]       [4]       [5]        [6]       SCAN CT [7]
           E CAL LO                                                                             SCAN POS 1
2          [8]          T1 CAL HI      T2 CAL HI       A         A         A          A         SCAN CT [15]
           F CAL HI     OTHER 1        OTHER 2
3          [16]         TEMP           TEMP            A         A         A          A         [23]
           XTAL 1+
4          [24]         LO 1 TEMP      LO 2 TEMP       A         A         A          A         [31]
           XTAL 1-
5          [32]         LO 3 TEMP      LO 4 TEMP       A         A         A          A         [39]
                        DICKE          DICKE
           XTAL 2+      LOAD           LOAD
6          [40]         1 TEMP         2 TEMP          A         A         A          A         [47]
                        DICKE          DICKE
           XTAL 2-      LOAD           LOAD
7          [48]         3 TEMP         4 TEMP          A         A         A          A         [55]
           XTAL 3+      TARGET 1A      TARGET 1B
8          [56]         TEMP           TEMP            A         A         A          A         [63]
           XTAL 3-      TARGET 2A      TARGET 2B
9          [64]         TEMP           TEMP            A         A         A          A         [71]
                        ANTENNA 1      ANTENNA 2
           XTAL 4+      BEARING        BEARING
10         [72]         TEMP           TEMP            A         A         A          A         [79]
           XTAL 4-      MOTOR          MOTOR
11         [80]         TEMP           TEMP            A         A         A          A         [87]
           -15 +5
SPACE      VOLTS
VIEW       [88]         RF CHASSIS     RF CHASSIS      A         A         A          A         [95]
BLACK
BODY       +5 VOLTS                                                                             SCAN POS 12
VIEW       [96]         PROG TEMP      PROG TEMP       A         A         A          A         SCAN CT [103]



                                                      4-20        NOAA POD Guide - Jan. 2002 Revision20
SCAN
TO                                                  CH 1      CH 2       CH 3       CH 4
SPOT     E ZERO       PROG TEMP      PROG TEMP      REF       REF        REF        REF         SCAN POS X
#1       [104]        [105]          [106]          [107]     [108]      [109]      [110]       SCAN CT [111]
Note: All 12-bit words; 112 words = 1 scan line = 25.6 seconds. Counts to 5 and resets every 128 seconds.
Numbers in brackets[ ] indicate the halfword number.

         The bit description for the MSU data is described in Tables 4.3.2.1-5 and 4.3.2.1-6.

         a)     Typical Format for all words except Scan Position-Line Count is described in
         Table 4.3.2.1-5.

              Table 4.3.2.1-5. Typical format for all MSU words (except scan position-line count).
                  Bit position                                       Description
           1 (MSB)                       = 1 when word is a Areal@ word;
                                         = 0 only for an Aall zero@ word.
           1                             = 1 when it is the first word in a scan;
                                         = 0 at all other words.
           0                             = 0 for the first 6 words.
           Z                             = 1 when in zero reference disable mode;
                                         = 0 at all other times.
           D11                           Data
           D10                           Data
           D9                            Data
           D8                            Data
           D7                            Data
           D6                            Data
           D5                            Data
           D4                            Data
           D3                            Data
           D2                            Data
           D1                            Data
           D0 (LSB)                      Data

         b)       Scan Position - Line Count (Word 7) is described in Table 4.3.2.1-6.

                     Table 4.3.2.1-6. Format of MSU scan position - line count (Word 7).
                 Bit Position                                      Description
           1 (MSB)                     = 1 when the word is a Areal@ word
           0                           = 0 when this is not the first word in a scan.
           1                           = 1 when this is the 8th word in the scan position.
           Z                           = 1 when in zero reference disable mode.
           S                           = 1 when in scan disabled mode;
                                       = 0 at all other times.
           R2                          Scan line count (reset by 128 sec sync).


                                                   4-21         NOAA POD Guide - Jan. 2002 Revision21
 R1                            Scan line count
 R0                            Scan line count
 E7                            Scan angle (position) data
 E6                            Scan angle (position) data
 E5                            Scan angle (position) data
 E4                            Scan angle (position) data
 E3                            Scan angle (position) data
 E2                            Scan angle (position) data
 E1                            Scan angle (position) data
 E0 (LSB)                      Scan angle (position) data

The scan position quality is contained in 16 bytes. The first 14 bytes contain quality
information for each of the 14 MSU scan positions. The last two bytes are spares. The
definition of the quality byte for each scan position is contained in Table 4.3.2.1-7.

                  Table 4.3.2.1-7. Format of the MSU scan position quality.
 Byte    Bit                                         Definition
 1      7       TIME ERROR - This scan line position contains data that is suspect due to a
                time error.
        6       MISSING DATA - The scan line position contains data fill due to a data gap.
                Each halfword of data fill is set to hex A7FFF@.
        5       DWELL - This scan line position contains data fill due to a dwell condition.
        4       DACS - This scan line position contains data that is suspect due to DACS QC
                error(s) (DROP LOCK, SYNC ERROR, FLYWHEEL, BIT SLIP, TIP
                PARITY).
        3       SCAN DISABLED - The instrument was in the scan disable condition during
                this scan line position. Normal Earth scanning is disrupted.
        2       SCAN SEQUENCE - A scan sequence error was detected in this scan line
                position. Normal Earth scanning may be disrupted.
        1       MIRROR SEQUENCE - A mirror sequence error was detected in this scan line
                position.
        0       SPARE

The 16-bit unpacked format for full copy MSU data has the same format as the "packed"
data described above except for the MSU channel data field. The unpacked format for
full copy MSU data for the channel data field has the format shown in Table 4.3.2.1-8.
Note that the 40 bytes of spare have been eliminated and the record length is 280 bytes.

      Table 4.3.2.1-8. Unpacked format for full copy MSU data (channel data field).
           Byte #                   .# Bytes                        Content
 161-162                      2                      Channel 1, scan spot 1
 163-164                      2                      Channel 2, scan spot 1
 165-166                      2                      Channel 3, scan spot 1
 167-168                      2                      Channel 4, scan spot 1
 169-170                      2                      Channel 1, scan spot 2


                                        4-22         NOAA POD Guide - Jan. 2002 Revision22
 ...                               ...                     ...
 247-248                           2                       Channel 4, scan spot 11
 249-250                           2                       Channel 1, Space view
 251-252                           2                       Channel 2, Space view
 253-254                           2                       Channel 3, Space view
 255-256                           2                       Channel 4, Space view
 257-258                           2                       Channel 1, Blackbody view
 259-260                           2                       Channel 2, Blackbody view
 261-262                           2                       Channel 3, Blackbody view
 263-264                           2                       Channel 4, Blackbody view
 265-280                           16                      Scan position quality

4.3.2.2        Selective Extract Subsets

When channels are selected for MSU data sets, the format of the MSU channel data is the
only field that changes from the format described in Section 4.3.2.1. One, two, or three
channels can be selected for the MSU data sets. Table 4.3.2.2-1 shows the format of the
MSU data field when Channels 1 and 4 are selected. Immediately following the MSU
channel values, the scan position quality is written starting in the first available halfword.

        Table 4.3.2.2-1. Format of MSU data field if Channels 1 and 4 are selected.
           Byte #                       # Bytes                        Content
 161-162                       2                             Channel 1, scan spot 1
 163-164                       2                             Channel 4, scan spot 1
 165-166                       2                             Channel 1, scan spot 2
 167-168                       2                             Channel 4, scan spot 2
 ...                           ...                           ...
 201-202                       2                             Channel 1, scan spot 11
 203-204                       2                             Channel 4, scan spot 11
 205-206                       2                             Channel 1, Space view
 207-208                       2                             Channel 4, Space view
 209-210                       2                             Channel 1, Blackbody view
 211-212                       2                             Channel 4, Blackbody view

4.4            SBUV/2 Data

This section describes the instrument and data characteristics of the Solar Backscattered
Ultraviolet system/Version 2 (SBUV/2). Section 4.4.1 contains a description of the
instrument and data characteristics. Section 4.4.2 contains general information about the
actual data for the three types of SBUV/2 data archived by SSB: 1) Level 1b; 2)
Historical Instrument File; and 3) Product Master File. Tape formats are not included in
this document but are thoroughly covered in a separate document entitled: Solar
Backscattered Ultraviolet Radiometer Version 2 (SBUV/2) User's Guide (November 15,
1990).



                                           4-23         NOAA POD Guide - Jan. 2002 Revision23
4.4.1         Instrument Description and Data Characteristics

The SBUV/2 is an operational remote sensor designed to map total ozone concentrations
and the vertical distribution of ozone in the earth's atmosphere on a global scale. The
purpose of the SBUV/2 instrument is to provide data on an operational basis, from which
the distribution of ozone can be determined on the ground. The SBUV/2 system was
chosen by NOAA because of the precision and reliability demonstrated by its
predecessors, the SBUV and BUV, developed by NASA and flown on the NIMBUS-7
and NIMBUS-4 satellites, respectively.

The SBUV/2 contains a scanning double monochromator and a cloud cover radiometer
(CCR) designed to measure ultraviolet (UV) spectral intensities. In its primary mode of
operation, the monochromator measures solar radiation Backscattered by the atmosphere
in 12 discrete wavelength bands in the near-UV, ranging from 252.0 to 339.8 nanometers
(nm), each with a bandpass of 1.1 nm. The total-ozone algorithm uses the four longest
wavelength bands (312.5, 317.5, 331.2 and 339.8 nm), whereas the profiling algorithm
uses the shorter wavelengths. The cloud cover radiometer operates at 379 nm (i.e.,
outside the ozone absorption band) with a 3.0 nm bandpass and was designed to measure
the reflectivity of the surface in the IFOV. The SBUV/2 also makes periodic
measurements of the solar flux by deploying a diffuser plate into the FOV to reflect
sunlight into the measurement.

The monochromator and the cloud cover radiometer are mounted so that they look in the
nadir direction with coincident FOV's of 11.3 by 11.3 degrees. As the satellite moves in
a sun synchronous orbit, the FOV traces 160 km wide paths on the ground. The earth
rotates approximately 26 degrees during each orbit. The satellite footprint moves at a
speed of about 6 km/sec. In discrete mode, a set of 12 measurements, one for each
discrete wavelength band, is taken every 32 seconds. The order of measurements is
252.0 to 339.9 nm and the integration time is 1.25 seconds per measurement. For each
monochromator measurement, there is a cloud cover radiometer measurement.

The SBUV/2 instrument can also measure the solar irradiance or the atmospheric
radiance with a continuous spectral scan from 160 to 400 nm in increments of nominally
0.148 nm.

4.4.2                 Magnetic Tape Formats

Three operational products based on the data collected from the SBUV/2 instrument (on
NOAA-9 and NOAA-11) are archived and available through SSB. All products are
archived on IBM 3480 cartridges. The NOAA-9 SBUV/2 data (Level 1b) have been
reprocessed for data from 1985 to the present. For NOAA-9, SSB archives the
reprocessed Level 1b data and the original Level 1b, and HIF data (no PMF). The
NOAA-11 Level 1b data has been reprocessed and is available in the archive (original
Level 1b not available).




                                        4-24         NOAA POD Guide - Jan. 2002 Revision24
SSB has no selection software for any type of SBUV/2 data. Tape-to-tape copies of the
data is the only option available at this time. Each of the three types of SBUV/2 data is
stored on one IBM 3480 cartridge per month of data.

4.4.2.1        Level 1b Data Set

The Level 1b data set contains: 1) all SBUV/2 sensor data and support data necessary for
the derivation of atmospheric ozone and solar flux; 2) instrument in-flight calibration data
and housekeeping functions for monitoring post-launch instrument changes; and 3)
prelaunch calibration factors, and computed current-day instrument calibration and
albedo correction factors to adjust the ozone algorithm for actual instrument performance.

The SBUV/2 sensor data consists of radiance and irradiance measurements taken in both
the discrete mode (12 wavelengths) and the sweep mode (1680 wavelengths at
approximately 2 intervals). The support data includes cloud and temperature data from
TOVS, ancillary data to initialize the algorithm, surface pressure data, and snow/ice data.

4.4.2.2        Product Master File

The Product Master File (PMF) contains the ozone information derived by the algorithm,
located in space and time, other meteorological information developed in support of the
ozone computation, parameters indicating the validity of the individual ozone retrievals,
and the radiance information derived from the SBUV/2 measurements.

4.4.2.3        Historical Instrument File

The Historical Instrument File (HIF) is a collection of data files, created by the
Instrument Support Subsystem which provide the data to characterize the instrument
performance and albedo correction over time.

4.5            Calibration of TOVS Data

TOVS thermal data values (HIRS/2 Channels 1-19, SSU Channels 1-3, and MSU
Channels 1-4) may be converted to brightness temperatures, and TOVS visible data
values (HIRS/2 Channel 20) may be converted to percent albedo, by the following
calibration procedures.

The format and order of the calibration coefficients is described in Sections 4.1.2.1,
4.2.2.1, 4.3.2.1 for HIRS/2, SSU, and MSU data, respectively. Once the calibration
coefficients have been extracted they must be scaled and normalized in that order. The
scale factors for the coefficients from lowest to highest in order are 222, 230, 244 and 256.
(The 0th order term is a constant or in this case the intercept value, and has a scale factor
of 222. Similarly, the 3rd order term has a scale factor of 256.) To scale the raw
calibration values, they must be divided by their respective scale factor. HIRS/2 users
should refer to adjustments necessary to obtain correct intercept values in Section 4.1.2.1.




                                          4-25         NOAA POD Guide - Jan. 2002 Revision25
Once the coefficients have been scaled, the raw data (in counts) should be normalized or
corrected for non-linearity by using the normalization coefficients which are supplied
with the calibration coefficients. The equation for the normalized count value Ci= is as
follows:

            C i' = Li, 0 + Li, 1 C + Li, 2 C2 + Li, 3 C3                                  4.5-1

where L is the normalization coefficient, C is the raw data in counts, subscript i indicates
the channel, and the subscripts 0, 1, 2, and 3 indicate the order of the normalization
coefficient. This is a generalized equation since the HIRS/2 calibration coefficients do
not contain a 3rd order normalization coefficient (i.e., drop the Li, 3 C3 term in Equation
4.5-1). When the condition of Li, 0 = 0, Li, 1 = 1, Li, 2 = 0 and Li, 3 = 0, is met, then Ci= =
Ci . This means that channel i is linear and no non-linearity correction is necessary. At
this time, the normalization coefficients for HIRS/2 and SSU data have this condition.
The scaled calibration coefficients and normalized data may now be used as described
below.

4.5.1           Thermal Channel Calibration

The scaled thermal channel zero order coefficients (intercept) are in units of mW/(m2-sr-
cm-1) , the 1st order coefficients (slope) are in units of mW/(m2-sr-cm-1) per count, etc.

The radiance measured by the sensor (Channel i) is computed as a function of the input
data value as follows:

                              '    2     '
                 Ei = Ai, 2 Ci + Ai, 1 Ci + Ai, 0                                       4.5.1-1

where Ei is the radiance value, in mW/(m2-sr-cm-1) , Ci= is the normalized count value
(computed from Equation 4.5-1), A is the calibration coefficient (auto or manual),
subscript i indicates the channel, and subscripts 0, 1 and 2 indicate the order of the
calibration coefficients. The Ai, 2 Ci=2 term in Equation 4.5.1-1 should be dropped for
SSU and MSU data.

For the SSU and MSU data, the conversion to "brightness" temperature from energy is
performed using the inverse of Planck's radiation equation (which is Equation 3.3.1-2 in
Section 3.3.1). The same values should be used for the constants C1 and C2, and the
central wave number values can be found in Section 1.4 (see the corresponding subsection
for the desired satellite).

For the conversion to "brightness" temperatures for the HIRS/2 data, the same procedure
is followed as with the MSU and SSU data, except that a band correction algorithm must
be applied to the results of the inverse of Planck's equation. The inverse of Planck's
equation actually produces an apparent brightness temperature, T*, which is corrected
using the following equation:


                                            4-26         NOAA POD Guide - Jan. 2002 Revision26
                                       *
                                        -b
                               T= T                                                   4.5.1-2
                                       c

where T is the corrected brightness temperature, and b and c are the band correction
coefficients which are supplied in Section 1.4 (see the corresponding subsection for the
desired satellite).


4.5.2          Visible Channel Calibration

The scaled visible channel calibration values are in units of percent lbedos for the zero
order term (intercept), percent lbedos/count for the 1st order term (slope), etc. The only
visible channel for the TOVS is the HIRS/2 Channel 20, so the equation to compute the
percent lbedos, B, is as follows:

                              '    2      '
                  B = A20, 2 C20 + A20,1 C20 + A20, 0                                 4.5.2-1

where A is the calibration coefficient (auto or manual), C20' is the normalized count
value for Channel 20, subscript 20 indicates Channel 20, and subscripts 0, 1, and 2
indicate the order of the calibration coefficients. At this time, the second order term (A20,
      2
2 C20' ) in Equation 4.5.2-1 can be dropped since A20, 2 is usually 0.




                                             4-27       NOAA POD Guide - Jan. 2002 Revision27
5.0            NESDIS Operational Products

SSB presently archives several different types of NESDIS operational polar orbiter
products. The products include atmospheric soundings, sea surface temperatures, heat
budget, mapped/gridded AVHRR data, TOVS and AVHRR Level 1b data (which have
been previously described in Sections 2, 3, and 4), and total and profile ozone data.
Tables 5.0-1 through 5 contain a detailed list of the specific NESDIS products which are
available. The sounding products in Table 5.0-1 are known as the TOVS sounding
products which are described in Section 5.1. The sea surface temperature products in
Table 5.0-2 are produced from quantitative processing of digital radiometric
measurements (AVHRR) and are described in Section 5.2. The mapped GAC
products contained in Table 5.0-3 (Polar Stereographic and Mercator GAC mosaics) are
described in Section 5.3. Heat budget products listed in Table 5.0-4 are described in
Section 5.4. The ozone products generated from the Solar Backscattered Ultraviolet
Radiometer Version 2 (SBUV/2) and listed in Table 5.0-5 are described in Section 5.5.

The TOVS sounding product information is derived from the three TOVS instruments.
These instruments consist of the HIRS/2, MSU, and SSU sensors (described in previous
sections) which measure the intensity of the upwelling radiation in the various spectral
intervals that occur at maxima over broad layers and depths of the atmosphere. These
radiance measurements are processed into Earth-located, calibrated radiance values,
"clear" radiances (radiances corrected for cloud effects and angle of view), estimates of
water vapor in three atmospheric layers (converted to precipitable water in these layers),
mean temperatures for selected atmospheric layers, tropopause height and temperature
estimates, and geopotential thickness of selected atmospheric layers.

The digital AVHRR data are processed into the quantitative products of global sea
surface temperatures and global radiation budget estimates.

The GAC infrared and visible data are processed into a basic set of sea surface
temperature (SST) observations at 8-km resolution (50-km prior to Nov. 17, 1981) over
the global oceans. All observations are values which have been integrated over an 8-km
diameter spot, however, they have a variable spacing, ranging from 8-km (contiguous) in
the U.S. coastal waters to 25-km in the open ocean. This data base is further processed to
generate gridded analyses at the regional, global, and local scales. The Regional-Scale
analyses (50 km resolution) are over five selected regions on a 0.5 degree
latitude/longitude grid. The Global-Scale analysis covers the global oceans at 100-km
resolution (1 degree latitude/longitude grid) and the Local-Scale analyses are at 14-km
resolution (.125 degree latitude/longitude grid) over eight selected regions.

The Radiation Budget archive consists of six types of similar data. One type is the
Monthly Radiation Budget consisting of daily values of day flux, night flux, absorbed
solar energy, and available solar energy for a month. These data are available in Polar
Stereographic and Mercator projections. Another type of Radiation Budget product is the
Seasonal Radiation Budget which has the same daily radiation fields as the Monthly
Radiation Budget product. But, in addition to Polar Stereographic and Mercator



                                            5-1         NOAA POD Guide - Jan. 2002 Revision1
projections, there is a smaller (45 x 45) polar chip included and, the data range over a
three-month season. A subset of the Seasonal Radiation Budget product is now available
for ten years in the Mercator format, and is called the Ten-year Mercator Radiation
Budget product. The fourth type of Radiation Budget product is the Monthly Mean
Radiation Budget which contains monthly averages for the above mentioned radiation
fields. These data are also available in Polar Stereographic and Mercator projections.
The fifth and sixth types of radiation budget data products are the seasonal mean and
annual mean. The seasonal mean product are averages over each season while the annual
mean product are averages calculated over each calendar year.

The gridded AVHRR products consist of mosaics of orbital passes of unmapped data and
the mapped AVHRR products consist of Mercator and Polar Stereographic map
projections. The mapped mosaics are of daytime visible and infrared, and nighttime
infrared imagery. Note that as of June 24, 1985, the Mercator mosaics became available
in digital form in addition to the already available Polar Stereographic mosaics.

There are three types of SBUV/2 ozone products. They are the 1B Capture product, the
Historical Instruments file product and the Product Master File product.

                      Table 5.0-1. TOVS Sounding Products on CCT
         Product Description              Accuracy Goals       Coverage/Spatial Resolution
 Layer-mean temperatures (K) for the      Surface-850 mb:     Global coverage. Nominal 250
 layers listed below:                       +/- 2.5K; 850-    km near the subsatellite track.
 surface - 850 mb; 850-700 mb; 700-        tropopause: +/-    Spacing and resolution increase
 500 mb; 500-400 mb; 400-300 mb;                2.25K;        with scan angle. Resolution will
 300-200 mb; 200-100 mb; 100-70 mb;         tropopause-2      be fixed at 250 km nominal.
 70-50 mb; 50-30 mb; 30-10 mb; 10-5       mb: +/- 3K; 2-4
 mb; 5-2 mb; 2-1 mb; 1-0.4 mb.               mb: +/- 3.5K
 Layer precipitable water (mm) for              +/- 30%       Same as above.
 these layers:
 surface-700 mb;
 700-500 mb;
 above 500 mb
 Tropopause pressure (mb) and              Pressure: +/- 50   Same as above.
 temperature                                     mb;
                                          temperature: +/-
                                             2.5 degrees
 Total ozone (Dobson units)                    +/- 15%        Same as above.
                                               tropical;
                                            +/- 50% polar




                                          5-2         NOAA POD Guide - Jan. 2002 Revision2
Equivalent Blackbody temperatures                 +/- 2K          Same as above.
(K) for 20 HIRS/2 stratospheric
channels, 4 MSU channels, and 3 SSU
channels
Cloud cover                                       +/- 20%         Same as above.


                      Table 5.0-2. Sea Surface Temperature Products
Product Description     Accuracy Goals        Spatial Resolution/           Format/Schedule
                                                Geographical
                                                   coverage
1) Sea Surface          +/- 1.5 degrees C     8 km                      CCT - weekly
Temperature             absolute; +/- 1.5     (nominal/Global)
Observations             degrees relative
2) Sea Surface             See above.         0.5 degree lat/long       Image - weekly;
Temperature                                   grid (50 km); 5           CCT - monthly
Regional-Scale                                regions
Analysis
3) Sea Surface             See above.         1 degree lat/long         Contour chart - weekly;
Temperature Global-                           grid (100 km)             CCT- bimonthly;
Scale                                                                   Image - daily
4) Sea Surface             See above.         0.125 degree lat/long     2 CCTs - monthly; Image
Temperature Local-                            grid (14 km); 8           - daily
Scale Analysis                                regions
5) Sea Surface             See above.         Global 2.5 degrees        CCT - yearly; Contour
Temperature                                   lat/long grid (250        chart - monthly
Monthly Mean                                  km)


                      Table 5.0-3. Mapped/Gridded AVHRR Product
Product Description       Accuracy Goals             Coverage/Spatial         Format/Schedule
                                                        resolution
1) Hemisphere           Nominal +/- 5 km for       Northern/Southern        Mapped imagery -
Mapped GAC Polar         polar and Mercator        Hemispheres 1024 x       CCT daily
mosaics IR and VIS        mapping location         1024; 14.8 km at
mosaics                                            Equator; 29.6 km at
                                                   poles




                                            5-3         NOAA POD Guide - Jan. 2002 Revision3
2) Mercator Mapped         See above.         360 degree longitude;    Mapped imagery
GAC Mosaics                                   40N-40S; 9.8 km at       CCT daily
IR/VIS                                        Equator, increasing      (beginning May 31,
                                              poleward                 1985)
3) Polar Mapped            See above.         North/South polar        Mapped - conforms
GAC composites                                Regions 1024 x 1024      to 7 day compositing
IR/VIS (minimum                                                        period
Brightness/maximum
temperatures)
4) Pass-by-pass         Nominal +/- 5 km      Global 4 km              Gridded imagery -
Gridded GAC              grid placement                                orbit by orbit
imagery VIS/IR (one
satellite)
5) Imagery from               n/a             Recorded data:           Imagery - recorded:
LAC data: both                                selectable; two 11.5     variable two 11.5
recorded and Direct                           minute                   minute
Readout (ungridded)                           segments/orbit.          segments/orbit.
                                              Direct Readout           Direct Readout all
                                              Continental U.S.         Continental U.S.


                        Table 5.0-4. Radiation Budget Products
  Product Description         Accuracy        Coverage/              Format/Schedule
                               Goals           Spatial
                                              Resolution
Monthly Radiation Budget   +/- 7 W/m2         Global;        CCT (January 1979 to present)
Parameters                 reflected          Observa-       a. 2.5 x 2.5 degree Mercator
                           outgoing energy    tions are      map array
                                              50km           b. 125 x 125 polar map array
                                                             2 times/day IR flux; 1
                                                             time/day reflected energy;
                                                             monthly (time average)
1. Daytime Longwave        +/- 7 W/m2         Global         See above.
Flux
2. Nighttime Longwave      +/- 7 W/m2         Global         See above.
Flux
3. Absorbed Solar          +/- 7 W/m2         Global         See above.
Radiation




                                        5-4        NOAA POD Guide - Jan. 2002 Revision4
4. Available Solar Energy   +/- 7 W/m2         Global        See above.
(calculated field to be
included in output form)

Seasonal Radiation Budget   +/- 7 W/m2         Global        CCT (June 1974 to present)
Parameters                                                   a. 125 x 125 polar stereo map
                                                             array
                                                             b. 45 x 45 polar stereo chip
                                                             array
                                                             c. 144 x 72 (2.5 x 2.5 degree)
                                                             Mercator array
                                                             Daily data for a 3-month
                                                             season
1. Daytime Outgoing         +/- 7 W/m2         Global        See above.
Longwave
2. Absorbed Solar Energy    +/- 7 W/m2         Global        See above.
3. Available Solar Energy   +/- 7 W/m2         Global        See above.
4. Nighttime Outgoing       +/- 7 W/m2         Global        See above.
Longwave

10-year Mercator Heat       +/- 7 W/m2         Global        CCT
Budget Parameters                                            a. 144 x 72 (2.5 x 2.5 degree)
                                                             Mercator map array
                                                             Daily data for 10 years. (June
                                                             1974 - March 1978, January
                                                             1979 - February 1986)
1. Daytime Outgoing         +/- 7 W/m2         Global        See above.
Longwave
2. Absorbed Solar Energy    +/- 7 W/m2         Global        See above.
3. Available Solar Energy   +/- 7 W/m2         Global        See above.
4. Nighttime Outgoing       +/- 7 W/m2         Global        See above.
Longwave

Monthly Mean Heat           +/- 7 W/m2         Global        CCT (January 1979 to present)
Budget Parameters                                            a. 144 x 72 (2.5 x 2.5 degree)
                                                             Mercator map array
                                                             b. 125 x 125 Polar stereo map
                                                             array
1. Daytime IR Flux          +/- 7 W/m2         Global        See above.



                                         5-5       NOAA POD Guide - Jan. 2002 Revision5
2. Nighttime IR Flux          +/- 7 W/m2           Global        See above.
3. Absorbed Solar Energy      +/- 7 W/m2           Global        See above.
4. Available Solar Energy     +/- 7 W/m2           Global        See above.


                            Table 5.0-5. SBUV/2 Ozone Products
             Product Description                   Accuracy Goals           Coverage/Spatial
                                                                              Resolution
Total Ozone (Dobson units)                                  1%                   Global
Layer Ozone (Dobson units), layers:                         5%                   Global
   Layer number         Pressure range (mb)
         1                   surface - 250
         2                    250 - 125
         3                     125 - 63
         4                     63 - 31
         5                     31 - 16
         6                      16 - 8
         7                       8-4
         8                       4-2
         9                       2-1
         10                     1 - 0.5
         11                   0.5 - 0.25
         12                   0.25 - 0.1
Level Ozone (micrograms/gram), levels:                      5%                   Global
   Level number             Pressure (mb)
         1                       0.3
         2                       0.4
         3                       0.5
         4                       0.7


                                             5-6       NOAA POD Guide - Jan. 2002 Revision6
5    1.0
6    1.5
7    2
8    3
9    4
10   5
11   7
12   10
13   15
14   20
15   30
16   40
17   50
18   70
19   100




           5-7   NOAA POD Guide - Jan. 2002 Revision7
5.1            TOVS Sounding Product

NESDIS currently has the capability of producing a maximum of 100,000 soundings
every 24 hours from two operational spacecraft. Up until March 9, 1992, the soundings
were 250 km resolution and only those classified as "good" were archived. Beginning
March 9, 1992, all the soundings were included ("good" and "redundant", not sampled)
on the archive tape with their resolution increased to 80 km. These soundings are
provided to SSB on a weekly basis.

Section 5.1.1 contains a description of the format used for the TOVS Sounding Product
between January 1979 and March 8, 1992. As of March 9, 1992, a modified format for
the TOVS Sounding Product was implemented because of a change in archive media -
seven days of soundings are written to one IBM 3480 cartridge each week. A description
of this format is contained in Section 5.1.2.

5.1.1                 TOVS Sounding Product (Jan. 1979 - March 8, 1992)

The data volume required for the TOVS Sounding Product for one week for one satellite
is approximately one-third of a 9-track, 6250 BPI tape. Therefore, when there is only one
operational satellite, three weeks worth of sounding data can be stacked on one CCT.
However, when there are two operational satellites, the sounding data will be intermixed
and in chronological order on one weekly CCT.

Individual soundings stored on tape are formatted according to the NMC/NESDIS Data
Set Format which is described in detail later in this section. Each tape contains a data
directory found at the beginning of the tape which will describe the contents of the tape.
The data directory acts as a housekeeping file and consists of two parts: 1) an element
containing directory information, and 2) the elements related to the data on the tape. The
purpose of the NMC/NESDIS archive housekeeping file is to aid users in determining the
location of time categorized, satellite-derived soundings on the tape. The end of each
group of time-categorized soundings, as described by the individual data directory
elements, is indicated by an end of file (EOF). A double EOF marks the end of data on
tape as described by the last directory element in the housekeeping file. Together, the
EOF markers and the housekeeping file are intended to provide the user with a means of
selectively choosing soundings from the tape.

The format of the NMC/NESDIS archive housekeeping file is in two parts. The first part
of the file is the Directory Information Element which contains 20 bytes or ten 2-byte
words in the format shown in Table 5.1.1-1.

                        Table 5.1.1-1. Directory Information Element
  Byte #                                          Contents
      1-2    Number of data directory elements in housekeeping file
      3-6    Total number of soundings (reports) on the tape


                                           5-8         NOAA POD Guide - Jan. 2002 Revision8
    7-8       Processing year (2 digits)
   9-10       Processing month (2 digits)
   11-12      Processing day (2 digits)
   13-20      Spares (denoted by “666610")

The second part of the housekeeping file is the Data Directory Element which contains 20
bytes per element in the format shown in Table 5.1.1-2.

                             Table 5.1.1-2. Data Directory Element
     Byte #                                           Contents
       1-2          Time category of reports stored
       3-4          Number of reports in time category
       5-6          Year of reports (Century x 256 + year)
       7-8          Month and day of reports (Month x 256 + day)
      9-10          Time of day (UTC) of earliest report (Hours x 256 + minutes)
      11-12         Time of day (UTC) of latest report (Hours x 256 + minutes)
      13-20         Spares (denoted by “666610")

Digital data may be selected from the TOVS Sounding Product tapes by time and/or area.
Each record that contains any of the selection criteria will be included in its entirety.
Note: if the TOVS Sounding Product selection software is run, the housekeeping file is
not included with the selected data. Using the selection software, a 1600 BPI CCT holds
approximately 131,000 soundings, while a 6250 BPI CCT holds approximately 455,000
soundings. Specific orbits cannot be selected with the existing software.

The time category (listed as the first two bytes of the Data Directory Element) is defined
in Table 5.1.1-3. If the value of the time category number equals 10 + the category
number, it will denote that the soundings for that data directory element are of bad
quality.

                                  Table 5.1.1-3. Time Category
               Category Number                                   Time Range (UTC)
                        1                                            0000 - 0259
                        2                                            0300 - 0559



                                             5-9         NOAA POD Guide - Jan. 2002 Revision9
                       3                                          0600 - 0859
                       4                                          0900 - 1159
                       5                                          1200 - 1459
                       6                                          1500 - 1759
                       7                                          1800 -2059
                       8                                          2100 - 2359

The overall structure of each TOVS Sounding Product archive tape is shown in Figure
5.1.1-1. It shows the n+1 elements in the housekeeping file and the corresponding TOVS
soundings files which are in the NMC/NESDIS Data Set Format.

                Figure 5.1.1-1. Structure of TOVS Sounding Product Tape
 Directory Information Element
   Data Directory Element #1
   Data Directory Element #2                                             Housekeeping File
   Data Directory Element #3
   ...
   Data Directory Element #n                                EOF
 TOVS Soundings described by Data Directory Element #1        EOF
 TOVS Soundings described by Data Directory Element #2        EOF
 ...
                                                                                Data Files
 TOVS Soundings described by Data Directory Element #n        EOF
 TOVS Quality information (since 1989)                        EOF
                                                            EOF

The TOVS Sounding Product tape has a logical record length of 280 bytes and a block
size (physical record length) of 6,440 bytes. However, the housekeeping file has a
variable length physical record. It ranges from a minimum of 280 bytes to a maximum of
3080 bytes because of the variable nature of the directory. The 6,440-byte block size
holds 23 reports of 280 bytes each. Thus, each report occupies one logical record. A
missing or undefined data value is denoted by "777710", a spare is "666610", and an end-
of-report is indicated by "888810". The TOVS Sounding data files are written in the
NMC/NESDIS Data Set Format. This format is in binary and contains 44 bytes of
documentation and 236 bytes of Sounding Products/information for a maximum of seven
data type categories. The format for the documentation portion is contained in Table
5.1.1-4.



                                        5-10        NOAA POD Guide - Jan. 2002 Revision10
         Table 5.1.1-4. NMC/NESDIS Documentation Format
Byte #                                      Content
 1-2     Satellite Identification (see Section 2.0.2)
 3-4     Year (last two digits) x 256 + Month
 5-6     Day x 256 + Hour (UTC)
 7-8     Minutes x 256 + Seconds (UTC)
9-10     Latitude (degrees x 100, +N, -S, Range: +90 to -90)
11-12    Longitude (degrees x 100, +E, -W, Range: +180 to -180)
13-14    Solar Zenith Angle (degrees x 100, +Day, -Night, Range: +90 to -90)
15-16    Land/Sea Indicator (if land, surface elevation in meters; if sea, zero)
17-18    Surface (skin) temperature (K x 10)
19-20    Estimated Surface Model Pressure (mb x 10)
21-22    Instrument and/or Channel combination used to obtain various products
23-24    Retrieval Method
25-26    Standard Deviation of Low-level HIRS/2 Channel (7) (K x 100, range: 0 to
         10)
27-28    Standard Deviation of Mid-level HIRS/2 Channel (5) (K x 100, range: 0 to
         10)
29-30    Average value of N*, range: 0 to 1 (dimensionless x radiance values when
         there are some clouds obstructing the surface.)
31-32    Superswath Box counter and minibox (Superswath x 1000 + Box counter x
         10 + minibox)
33-34    Sea Surface Temperature (K x 10). SST over ocean, skin temperature over
         land.
35-36    Day of Month and Hour (UTC) when Edit Flag is written to file. Scaling:
         (Day x 256) + Hour
37-38    Minute and Second (UTC) when Edit Flag is written to file. Scaling:
         (Minute x 256) + Seconds
39-40    TOVS Filter Flag: 0 = sounding is good; 1 = sounding is redundant



                               5-11          NOAA POD Guide - Jan. 2002 Revision11
      41-44        Special Counter for 7-Day Archive Tape (address of start on disk)
 Note: A value of N* between 0 and 1000 indicates that the N* method was used. A value of
 "7777" indicates missing data and implies that the HIRS radiances are completely clear and
 the N* method was not used. A value of "9211" means that the HIRS radiances are
 completely cloudy and the user should check the channel combination flags to determine
 which channels were used.

A superswath is defined as the 40 scan lines of HIRS/2 data between calibration modes,
while a box is 7 lines x 9 spots, and a minibox is 3 lines x 3 spots. There are a maximum
of 26 superswaths per orbit.

Table 5.1.1-5 contains the format of the sounding products/information (arranged in
categories). Category 6 contains radiometric information supplied in the form of
equivalent Blackbody or brightness temperatures. These can be transformed to radiances
(mW/(m2-sr-cm-1)) by application of the Planck function. The Planck function requires
channel central wave numbers and temperature-adjustment coefficients which are
spacecraft/instrument dependent and available in Section 1.4.

            Table 5.1.1-5. NMC/NESDIS Sounding Products/Information Format
   Byte #                                         Content
                Category 1 - Layer Mean Temperature (Maximum 15 layers)
   45-46      Pressure at lower boundary (mb x 10)
   47-48      Pressure at upper boundary (mb x 10)
   49-50      Layer-mean temperature (K x 10)
   51-52      Quality (K x 10)
   53-164     Repeat of Category 1 data for 14 more layers
                Category 2 - Layer Precipitable Water (Maximum 3 layers)
  165-166     Pressure at lower boundary (mb x 10)
  167-168     Pressure at upper boundary (mb x 10)
  169-170     Layer Precipitable Water (mm)
  171-172     Quality (percent)
  173-188     Repeat of Category 2 data for two more layers
                            Category 3 - Tropopause Parameters
  189-190     Pressure (mb x 10)


                                         5-12        NOAA POD Guide - Jan. 2002 Revision12
  191-192     Temperature (K x 10)
  193-194     Quality (mb x 10)
  195-196     Spare
                                      Category 4 - Ozone
  197-198     Total ozone amount (Dobson units)
  199-200     Quality (percent)
                                   Category 5 - Cloud Cover
  201-202     Pressure (mb x 10)
  203-204     Amount (Percent)
                               Category 6 - Sounding Radiances
  205-244     Twenty HIRS/2 Channel Equivalent Blackbody Temperatures (K x 64 except for
              Channel 20 which has K x 16)
  245-252     Four MSU Channel Equivalent Blackbody Temperatures (K x 64)
  253-258     Three SSU Channel Equivalent Blackbody Temperatures (K x 64)
  259-260     Spare
  261-276                                  New Category(s) Spare
  277-278     Spare
  279-280     End of Report

The documentation portion of the NMC/NESDIS Data Set Format contains two bytes
(bytes 21-22) which indicate the instrument and/or channel combination used to obtain
various products. ICC represents the value in this byte, and is defined as shown in
Equation 5.1.1-1,
                      ICC = 4096 Z + 256Y + 16X + 4W + V                            5.1.1-1

Table 5.1.1-6 describes the variables that comprise ICC.

                         Table 5.1.1-6. Variables that Comprise ICC
    V       denotes channel combinations used to obtain layer precipitable water for the layers:
            surface to 700 mb, 700 to 500 mb, and 500 to 300 mb. V can have the following
            values:
            0 No Retrieval



                                         5-13         NOAA POD Guide - Jan. 2002 Revision13
    1 HIRS/2 + MSU
    2 HIRS/2
    denotes channel combinations used to obtain tropopause temperature and pressure.
    W can have the following value:

W   0 No Retrieval
    1 HIRS’ + MSU
    2 HIRS/2
    denotes channel combinations used to obtain total ozone. X can have the following
    values:
    0 No Retrieval

X   1 HIRS/2 (1, 2, 3, 8, 9, 16, 17) + MSU (4)
    2 HIRS/2 (1, 2, 3, 8, 9, 16, 17)
    3 HIRS/2 (1, 2, 3, 9, 17) + MSU (4)
    4 HIRS/2 (1, 2, 3, 9, 17)
    denotes channel combinations used to obtain mean temperature for the layers:
    surface to 850 mb, 850 to 700 mb, 700 to 500 mb, 500 to 400 mb, 400 to 300 mb,
    300 to 200 mb, 200 to 100 mb. Y can have the following values:
    0 No Retrieval
    1 HIRS/2 + MSU
Y   2 HIRS’ + MSU
    3 HIRS/2
    4 MSU
    5 HIRS’ + MSU + SKINTK (ocean only)
    6 MSU + SKINTK (ocean only)
    denotes channel combinations used to obtain mean temperature for the layers; 100
    to 70 mb, 70 to 50 mb, 50 to 30 mb, 30 to 10 mb, 10 to 5 mb, 5 to 2 mb, 2 to 1 mb,
    1 to 0.4 mb. Z can have the following values:
    0 No Retrieval
Z
    1 HIRS’ + SSU + MSU (3,4)
    2 HIRS’ + MSU (3,4)
    3 SSU + MSU (3,4)


                                 5-14        NOAA POD Guide - Jan. 2002 Revision14
            4 HIRS’ + SSU
            5 HIRS’
            6 MSU (3,4) (Output will terminate at 10 mb since there is no meaningful data
            above that level in this case.)
 Note that HIRS' is equivalent to HIRS/2 Channels 1 (668 cm-1), 2 (679 cm-1), 3 (691 cm-1),
 and 17 (2360 cm-1).

The retrieval method is contained in bytes 23 and 24 of the documentation portion of the
NMC/NESDIS Data Set Format. METREC represents the value in the two bytes, and is
defined by Equation 5.1.1-2,

                             METREC = 256A + 16B +C                                5.1.1-2

Table 5.1.1-7 describes the variables that comprise METREC.

                      Table 5.1.1-7. Variables that Comprise METREC.
                      0         No HIRS/2 data.
     A=               1         Clear radiances are derived from completely clear spots.
                      2         Clear radiances derived from the N* approach.
                      0         No HIRS/2 data.
                      1         All HIRS/2 channels were used in the retrieval.
     B=
                      2         The tropopause HIRS/2 channels were unusable due to clouds
                                and only stratospheric channels were used in the retrieval.
                      0         A statistical retrieval method was used.

     C=               1         The minimum information retrieval was used.
                      2         The minimum information retrieval was attempted, but the
                                statistical retrieval was used.

5.1.1.1        TOVS Quality Information File (Sept. 1989 - March 8, 1992

Since September 1989, TOVS quality information as required by NOAA's Climate and
Global Change Program, has been generated and written to the last file (usually file 58)
of the TOVS Sounding Product archive tape. This quality information is cumulative
(e.g., the quality information written during the week of Jan. 8, 1990, contains quality
statistics from July 1989 through Jan. 7, 1990). Statistics were generated beginning in
July 1989 but were not written to the archive tape until September 1989.




                                         5-15         NOAA POD Guide - Jan. 2002 Revision15
Table 5.1.1.1-1 shows the general structure of the TOVS quality information file. The
housekeeping record (record 1) has the format shown in Table 5.1.1.1-2, while the
directory records (records 2 to 8) have the format shown in Table 5.1.1.1-3. Data records
(records 9 to 848) have the format shown in Table 5.1.1.1-4. Each directory record
contains 120 directory elements. Each element is a group of 12 words containing
information on the corresponding data record (described in Table. 5.1.1.1-4).

         Table 5.1.1.1-1. General Structure of the TOVS Quality Information File.
    Record #                                          Contents
        1          Housekeeping record (see Table 5.1.1.1-2)
       2-8         Directory records (see Table 5.1.1.1-3)
      9-848        Data records (see Table 5.1.1.1-4)


 Table 5.1.1.1-2. Format of the Housekeeping Record for the TOVS Quality Information
                                          file.
  Word # (I*4)                                        Contents
        1          Total number of records in the file (848)
        2          Last record updated
        3          Last record updated at the time the file was archived on tape
        4          Beginning record number of directory (2)
        5          Beginning record number of data (9)
      6-720        Spares (fill = -110)


   Table 5.1.1.1-3. Format of Directory Record for the TOVS Quality Information File.
  Record # (I*2)                                        Contents
            2         Directory of data records 9 - 128 (fill = -110)
            3         Directory of data records 129 - 248
            4         Directory of data records 249 -368
            5         Directory of data records 369 - 488
            6         Directory of data records 489 - 608
            7         Directory of data records 609 - 728
            8         Directory of data records 729 - 848



                                          5-16          NOAA POD Guide - Jan. 2002 Revision16
     Table 5.1.1.1-4. Format of the Data Record for TOVS Quality Information File.
     Word #                                         Contents
        1           Start month
        2           Start day
        3           Start year
        4           End month
        5           End day
        6           End year
        7           Plot title code
        8           Data type code
        9           Satellite ID
        10          Record number
        11          Thickness/Virtual temperature indicator
        12          Spare (fill = -110)

Table 5.1.1.1-5 contains the format of the TOVS quality information data records. The
format included in Table 5.1.1.1-5 is for records 9 to 848, which are data records (all
words are INTEGER*2 with fill = -110. These 1440 words are repeated for each week on
the file.

             Table 5.1.1.1-5. Format of TOVS Quality Information Data Records
   Word #                                 Description                              Scaling
    1-240        Zone 1 (90N - 60N)                                                   n/a
     1-60         Mean (retrieval - radiosonde)                                       n/a
     1-30            Temperature (1000 - 10 mb)                                      100
    31-44            Thickness/Virtual Temperature (1000 - 10 mb)                     10
      45             Tropopause temperature                                          100
      46             Tropopause pressure                                              10
    47-60            Mixing ratio (1000 - 350 mb)                                    100
    61-120        Root Mean Square (Retrieval -radiosonde)                            n/a
    61-90            Temperature (1000 - 10 mb)                                      100


                                          5-17      NOAA POD Guide - Jan. 2002 Revision17
    91-104           Thickness/Virtual Temperature (1000 - 10 mb)                        10
        105          Tropopause temperature                                              100
        106          Tropopause pressure                                                 10
   107-120           Mixing ratio (1000 - 350 mb)                                        100
   121-180        Standard deviation (σ)                                                 n/a
   121-150           Temperature (1000 - 10 mb)                                          100
   151-164           Thickness/Virtual Temperature (1000 - 10 mb)                        10
        165          Tropopause temperature                                              100
        166          Tropopause pressure                                                 10
   167-180           Mixing ratio (1000 - 350 mb)                                        100
   181-240        Sample size (N)                                                        n/a
   181-210           Temperature (1000 - 10 mb)                                           1
   211-224           Thickness/Virtual Temperature (1000 - 10 mb)                         1
        225          Tropopause temperature                                               1
        226          Tropopause pressure                                                  1
   227-240           Mixing ratio (1000 - 350 mb)                                         1
   241-480       Zone 2 (60N to 30N). Format same as for Zone 1.                         n/a
   481-720       Zone 3 (30N to 0). Format same as for Zone 1.                           n/a
   721-960       Zone 4 (0 to 30S). Format same as for Zone 1.                           n/a
   961-1200      Zone 5 (30S to 60S). Format same as for Zone 1.                         n/a
  1201-1440      Zone 6 (60S to 90S). Format same as for Zone 1.                         n/a


5.1.2         TOVS Sounding Product (March 9, 1992 - May 31, 1998)

Beginning with the data for March 9, 1992, the format for the TOVS Sounding Product
has changed. This section describes the new format and how it relates to the old format.

The TOVS sounding product currently consists of a full resolution file, which replaces
the former archive of a sampled data set. Some of the changes which have been
implemented in this new format include the following:




                                         5-18        NOAA POD Guide - Jan. 2002 Revision18
       1) The number of words in each data record remains the same at 140 words.
       Each variable is INTEGER*2 and the logical record length is fixed at 280 bytes.

       2) The new format consists of one large file for all the TOVS data (instead of 57
       small files) plus a separate file containing the TOVS Quality information file.

       3) There is no longer a housekeeping file at the beginning of the data.

       4) The TOVS quality information file is contained in a separate file from the
       normal TOVS Sounding data and must be specifically ordered from SSB if
       desired.

       5) The archive media changed from 9 track 6250 bpi magnetic tape to IBM 3480
       cartridges.

The number of records on the cartridge varies from week to week. Before Sept. 21, 1992,
the data were blocked into 6440 byte physical records. Each physical record contained
23 logical records of 280 bytes each. To minimize space on the cartridge, the block size
was changed to 31,920 bytes beginning with the data on Sept. 21, 1992. Currently each
physical record (block) contains 114 logical records of 280 bytes each. Each logical
record comprises a report and is composed of 140 INTEGER*2 words (280 bytes). The
data are separated into three-hour time periods, thus there are eight possible time periods
in a day. The last two data records of each time period are fillers, i.e., every byte in the
record is set to a value of "-33310". Although the format of the old and the new TOVS
Sounding data records are very similar, for clarification purposes, the format for the new
data record is repeated in Table 5.1.2-1.

           Table 5.1.2-1. Format of New TOVS Sounding Product Data Record.
   Word #                                            Contents
       1        Satellite Identification (see Section 2.0.2)
       2        Year x 256 + Month
       3        Days x 256 + Hours (UTC)
       4        Minutes x 256 + Seconds
       5        Latitude (degrees x 100, +N, -S, range: +90 to -90)
       6        Longitude (degrees x 100, +E, -W, range: +180 to -180)
       7        Solar Zenith Angle (degrees x 100, range: 0 to 90, 90=night)
       8        Land/Sea indicator (if land, surface elevation in meters; if sea, zero)
       9        Surface temperature (K x 10)
      10        Estimated pressure at base of sounding (mb x 10)


                                          5-19         NOAA POD Guide - Jan. 2002 Revision19
 11     Instrument and/or channel combination
 12     Retrieval method
 13     Standard deviation for low-level channel (K x 100, range: 0 to 10)
 14     Standard deviation for medium-level channel (K x 100, range: 0 to 10)
 15     Mean value of N* (N* x 1000, range: 0 to 1)
 16     Superswath, box and minibox counter (superswath x 1000 + box counter x 10 +
        minibox)
 17     Sea Surface Temperature (K x 10)
 18     Day of month and hour (UTC) when edit flag is written to file (Day x 256 +
        hour)
 19     Minute and second when edit flag is written to file (Minute x 256 + seconds)
 20     TOVS filter flag (range: 0 to 3)
21-22   Spare
                 Words 23-82 are Layer mean temperatures
 23     Pressure at low boundary (mb x 10)
 24     Pressure at upper boundary (mb x 10)
 25     Layer-mean temperature (K x 10)
 26     Quality (K x 10)
27-82   Same as words 23-26 for the other 14 layers
                Words 83-94 are for layer precipitable water:
 83     Pressure at lower boundary (mb x 10)
 84     Pressure at upper boundary (mb x 10)
 85     Layer precipitable water (mm)
 86     Quality (percent)
87-94   Same as words 83-86 for the other 2 layers
 95     Tropopause pressure (mb x 10)
 96     Tropopause temperature (K x 10)
 97     Tropopause quality (percent)
 98     Spare



                                 5-20        NOAA POD Guide - Jan. 2002 Revision20
      99        Total ozone amount (Dobson units)
     100        Total ozone quality (percent)
     101        Cloud cover pressure (mb x 10)
     102        Cloud cover amount (percent)
                         Words 103-130 are for sounding radiances:
   103-121      Equivalent Blackbody temperatures used to obtain HIRS/2 Ch. 1-19, (K x 64)
     122        Equivalent Blackbody temperatures used to obtain HIRS/2 Ch. 20, (K x 16)
   123-126      Equivalent Blackbody temperatures used to obtain MSU Ch. 1-4 (K x 64)
   127-129      Equivalent Blackbody temperatures used to obtain SSU Ch. 1-3 (K x 64)
     130        Spare
     131        Stability departure
     132        Stability departure time difference
   133-139      Spares
     140        End of report indicated by “8888"
 Note: A value of N* between 0 and 1000 indicates that the N* method was used. A value of
 "7777" indicates missing data and implies that the HIRS radiances are completely clear and the
 N* method was not used. A value of "9211" means that the HIRS radiances are completely
 cloudy and the user should check the channel combination flags to determine which channels
 were used.

Weekly (on a seven day cycle beginning with Monday), sounding data for two satellites
are written onto an IBM 3480 cartridge (which is full). SSB has selection software for
this version of the TOVS Sounding Product. Digital data may be selected from the
TOVS Sounding Product tapes by time and/or area. Each record that contains any of the
selection criteria will be included in its entirety.

The instrument and/or channel combination described in word 11 is represented by ICC,
which is defined by Equation 5.1.2-1:

                     ICC = 4096Z + 256Y + 16X + 4W +V                              5.1.2-2

Table 5.1.2-2 describes the variables that comprise ICC.




                                         5-21         NOAA POD Guide - Jan. 2002 Revision21
                 Table 5.1.2-2. Variables that Comprise ICC
    denotes channel combinations used to obtain layer precipitable water for the layers:
    surface to 700 mb, 700 to 500 mb, and 500 to 300 mb. V can have the following
    values:
V   0 No Retrieval
    1 HIRS + MSU
    2 HIRS
    denotes channel combinations used to obtain tropopause temperature and pressure.
    W can have the following values:

W   0 No Retrieval
    1 HIRS’ + MSU
    2 MSU
    denotes channel combinations used to obtain total ozone. X can have the following
    values:
    0 No Retrieval

X   1 HIRS (1, 2, 3, 8, 9, 16, 17) + MSU (4)
    2 HIRS (1, 2, 3, 8, 9, 16, 17)
    3 HIRS (1, 2, 3, 9, 17) + MSU (4)
    4 HIRS (1, 2, 3, 9, 17)
    denotes channel combinations used to obtain mean temperature for the layers:
    surface to 850 mb, 850 to 700 mb, 700 to 500 mb, 500 to 400 mb, 400 to 300 mb,
    300 to 200 mb, 200 to 100 mb. Y can have the following values:
    0 No Retrieval
    1 HIRS + MSU
    2 HIRS’ + MSU
Y
    3 HIRS
    4 MSU
    5 HIRS’ + MSU + SKINTK (ocean only)
    6 MSU + SKINTK (ocean only)
    Note: SKINTK is no longer used, so Y values of 2 and 5 are identical, as well as Y
    values of 4 and 6.



                                 5-22          NOAA POD Guide - Jan. 2002 Revision22
            denotes channel combinations used to obtain mean temperature for the layers; 100
            to 70 mb, 70 to 50 mb, 50 to 30 mb, 30 to 10 mb, 10 to 5 mb, 5 to 2 mb, 2 to 1 mb,
            1 to 0.4 mb. Z can have the following values:
            0 No Retrieval
            1 HIRS’ + SSU + MSU (3,4)

    Z       2 HIRS’ + MSU (3,4)
            3 SSU + MSU (3,4)
            4 HIRS’ + SSU
            5 HIRS’
            6 MSU (3,4) (Note: If Z = 6, output will terminate at 10 mb, since there is no
            meaningful information above that level in this case.)
 Note that HIRS' is equivalent to HIRS/2 Channels 1 (669 cm-1), 2 (679 cm-1), 3 (690 cm-1),
 and 17 (2358 cm-1).

The retrieval method in word 12 is indicated by MR, where MR is defined by Equation
5.1.2-2:

                                MR = 256X + 16Y Z                                  5.1.2-2
Table 5.1.2-3 describes the variables that comprise MR.

                         Table 5.1.2-3. Variables that Comprise MR
 X indicates:       0        No HIRS/2 data.
                    1        Clear radiances are derived from completely clear spots.
                    2        Clear radiances are derived from the N* method.
 Y indicates:       0        No HIRS/2 data.
                    1        All HIRS/2 channels were used.
                    2        Tropospheric HIRS/2 channels were unusable due to clouds only
                             stratospheric channels were used.
 Z indicates:       0        Statistical retrieval method was used.
                    1        Minimum information retrieval was used.
                    2        Minimum information retrieval attempted, but statistical retrieval
                             used.
                    3        No HIRS.



                                         5-23         NOAA POD Guide - Jan. 2002 Revision23
Radiometric information are supplied in the form of equivalent Blackbody (or
"brightness") temperatures (K). These can be transformed into radiances (mW/(m2-sr-
cm-1)) by application of the Planck function. Parameters required for such transformation
such as channel central wave numbers and temperature adjustment coefficients are
spacecraft instrument dependent and are supplied in respective subsections of Section 1.4
for each satellite.

Spares are indicated by "666610", missing or undefined values are indicated by "777710"
and end of report is denoted by "888810".

The TOVS filter flag in word 20 indicates that one of the following conditions is true:
      0      Sounding is good
      1      Sounding is redundant

Word 17 contains the sea surface temperature value when over ocean and the skin
temperature when over land.

5.1.2.1        TOVS Sounding Quality Information File (March 9, 1992 - Present)

The format of the TOVS sounding quality information file is drastically different from
the old format. This file is an on-going accumulation of weekly statistics for the TOVS
Sounding Product. It contains a housekeeping record which has 720 INTEGER*4 words.
The first five words of the housekeeping record are contained in Table 5.1.2.1-1. Words
1 and 3 are the same since the entire file is archived. Word 4 is set to a value of two
since the housekeeping record is the first record on the file and the directories follow.

                    Table 5.1.2.1-1. Format of the Housekeeping Record.
  Word # (I*4)                                         Contents
          1         Total number of records on file
          2         Last record updated
          3         Last record updated at time of archive
          4         Beginning record number of directory
          5         Beginning record number (i.e., start of data for first directory)
      6-720         Zero filled


The directories are dimensioned as 12 x 120 INTEGER*2 arrays. The number of records
containing directories can be computed from the housekeeping record: word 5 minus
word 4. Table 5.1.2.1-2 contains the format of the directories.




                                          5-24         NOAA POD Guide - Jan. 2002 Revision24
                       Table 5.1.2.1-2. Format of the Directory Record
    Word # (I*2)                                        Contents
          1            Starting month of data period (period is a week)
          2            Starting day
          3            Starting year
          4            Ending month of data period
          5            Ending day
          6            Ending year
          7            Plot title code
          8            Data type code
          9            Satellite ID
         10            Record number of data in file
        11-12          Spares (“FFFFZ”)
      13-1440          Repeat of word numbers 1-12 for each directory record


Table 5.1.2.1-3 contains the format for the quality information record. Each week, one
record of data is written for each operational spacecraft for the clear, N* and cloudy
cases. Therefore, in one week for two operational satellites, six data records are created.
The data records contain 1440 INTEGER*2 words. Each record contains data for six
latitude zones: 90N to 60N, 60N to 30N, 30N to 0, 0 to 30S, 30S to 60S, and 60S to 90S.
Unless otherwise specified when ordering, the current quality information file will not be
included with a customer's order of TOVS Sounding Product data.

               Table 5.1.2.1-3. Format of New TOVS Quality Information Record
  Word # (I*2)                                Description                             Scaling
       1-240         Zone 1 (90N-60N)
       1-120                             Retrieval temperature (at 30 TOVS levels)
       1-30          Mean (K)                                                          1000
       31-60         Root mean square                                                  1000
       61-90         Standard deviation                                                1000
      91-120         Sample size                                                       1000



                                            5-25       NOAA POD Guide - Jan. 2002 Revision25
        121-176                                     Thickness (at 14 levels)
        121-134        Mean (m)                                                             100
        135-148        Root mean square                                                     100
        149-162        Standard deviation                                                   100
        163-176        Sample size                                                          100
        177-180                                    Tropopause temperature
          177          Mean (K)                                                            1000
          178          Root mean square                                                    1000
          179          Standard deviation                                                  1000
          180          Sample size                                                         1000
        181-184                                     Tropopause pressure
          181          Mean (mb)                                                            100
          182          Root mean square                                                     100
          183          Standard deviation                                                   100
          184          Sample size                                                          100
        185-240                                    Mixing ratio at 14 levels
        185-198        Mean (g/kg)                                                         1000
        199-212        Root mean square                                                    1000
        213-226        Standard deviation                                                  1000
        227-240        Sample size                                                         1000
        241-480        Zone 2 (60N to 30N). Format same as Zone 1.
        481-720        Zone 3 (30N to 0). Format same as Zone 1.
        721-960        Zone 4 (0 to 30S). Format same as Zone 1.
        961-1200       Zone 5 (30S to 60S). Format same as Zone 1.
    1201-1440          Zone 6 (60S to 90S). Format same as Zone 1.

5.1.3              RTOVS Sounding Product (October 22, 1997 - present)

RTOVS is the Revised TOVS system introduced on October 22, 1997 for NOAA-14
processing and on November 19, 1997 for NOAA-11 processing. RTOVS uses the same
instruments as TOVS but newer software designed to easily transition to the new NOAA


                                            5-26           NOAA POD Guide - Jan. 2002 Revision26
KLM series of satellites. The format of the archive has been kept the same as TOVS
(fully described in Section 5.1.2), to ease data processing by users, although the data
volume is higher. There is a parallel archive of TOVS and RTOVS data through May
1998.

5.2            Sea Surface Temperature (SST) Products

SSB archives several NESDIS operational SST products. Once per week, NESDIS
produces a tape containing eight days (seven days prior to Nov. 1, 1986) of 8-km
resolution (50-km prior to Nov. 17, 1981) SST observations from a current operational
TIROS-N series satellite. Twice per month the daily 100-km (Global-Scale Analysis)
gridded SST fields produced from these observations are archived to tape. NESDIS
produced 500-km gridded SST fields (Climatic-Scale analysis) on a monthly basis until
Nov. 1, 1984, when this product was discontinued. NESDIS expanded the Regional-
Scale Analysis (50-km) from three regions to five regions on Aug. 1, 1986 and
introduced the 14-km gridded (Local-Scale analysis) SST fields over nine selected
regions on Jan. 1, 1986. Monthly means are produced from the observations on a 250-km
grid (SST Monthly Mean) and archived yearly. Any queries regarding SST products
should be directed to the National Climatic Data Center, Climate Services Division, 151
Patton Avenue, Asheville, NC 28801, where all but the latest CCTs containing SST data
are currently archived.

The 14-km gridded, 50-km gridded, and 100-km gridded SST fields are generated by
NESDIS in the SST Field Format which is described in Section 5.2.1. Section 5.2.2
describes the SST Observation File and the SST Monthly Mean is described in Section
5.2.3.

Most SST archive tapes contain a Header File which will usually be the first file on tape.
The Header File consists of one 400-byte physical record which contains some of the
information shown in Table 5.2-1.

                         Table 5.2-1. Format of the SST Header File
 Word #      # Bytes                    Content                                 Range
      1-20     80      Title of data set archived in File 2 of      1-80 characters with blank fill
                       this tape
  21-27        28      Data set name of disk data set               1-28 characters with blank fill
  28-29         8      Original archive tape number                  1-8 characters with blank fill
                                 Date of earliest data on tape:
      30        1      Year                                                      0-99
                1      Month                                                     1-12
                1      Day                                                       1-31


                                         5-27           NOAA POD Guide - Jan. 2002 Revision27
                1       Blank                                                   n/a
                                Date of most current data on tape:
    31          1       Year                                                   0-99
                1       Month                                                  1-12
                1       Day                                                    1-31
                1       Blank                                                   n/a
                    Date and time when data was archived from disk to tape:
    32          4       Year                                                   0-99
    33          4       Month                                                  1-12
    34          4       Day                                                    1-31
    35          4       Hour                                                   0-23
    36          4       Minute                                                 0-59
    37          4       Second                                                 0-59
    38          4       Number of records of data in File 2 of                  n/a
                        tape
    39          4       Number of files of data on the tape (not                n/a
                        counting Header file)
  40-100       244      Spare                                                   n/a

5.2.1          SST Field Format

All of the SST Field products (14-km gridded, 50-km gridded, and 100-km gridded) are
derived from the basic 8-km SST observations. An SST Field consists of a specific set of
information pertaining to global latitude and longitude intersections. Files have been
generated for 0.125 degree, 0.5 degree, and 1 degree latitude-longitude resolution (or 14-
km, 50-km, and 100-km resolution, respectively). The Global-Scale (1 degree resolution)
file includes the area from 180W to 179E longitude and from -70S to 70N latitude.
Using the SST observations as input, NESDIS produces Regional-Scale (50-km) SST
analyses and Local-Scale (14-km) SST analyses twice weekly by analyzing all the SST
observations obtained during the period since the last analysis.

All resolution field (accumulation) files consist of a Directory Record and a Field
Documentation Record, followed by Field Data Records for each field in the
accumulation file. Each file (except the Header File) begins with a Directory Record
which points to the Field Documentation Record for each field in the file. Details of the
Directory Record are contained in Section 5.2.1.1. The Field Documentation Record is



                                          5-28        NOAA POD Guide - Jan. 2002 Revision28
described in Section 5.2.1.2, and is always followed by a Field Data Record for each
latitude or row of the field. The Field Data Record is described in Section 5.2.1.3.

The fields will generally be arranged in chronological order. A field for a particular day
may be missing or repeated so one should examine the Field Documentation Record for
each field in the file to find that field spanning the time of interest. The Field
Documentation Record (the first record of each field) should be used in referencing the
data record for the field since it provides information concerning the organization, size,
and time period of the field.

After the Directory Record, there are NFIELDS fields. The first record of each field is a
Field Documentation Record which is followed by NRECS Field Data Records, one for
each latitudinal row in the field. Each row consists of 28 bytes of information for each
longitude or column forming a grid intersection plus 28 bytes at the end of the record (the
Latitudinal Row Identifier) containing the row number identification and the date and
time of the last analysis made for the field.

Prior to Nov. 1, 1984, a 500-km gridded SST (Climatic-Scale Analysis) product was
generated and included with the 50-km gridded fields on the monthly tape. This tape
contained five files, the first being the Header File previously described in Table 5.2-1.
The second file contained 36 500-km daily fields organized chronologically. The 500-
km fields contained 72 grid intersections in each row, one for each 5 degrees of longitude
from -180W eastward to 175E. The first physical record of the second file was the
Directory Record which pointed to the beginning address of each of the 36 fields. Each
field consisted of 30 logical records of 2044 bytes each, blocked into five 12,264-byte
physical records. Since there were 36 fields, the data spanned slightly more than a
month. The third, fourth, and fifth files of this tape (prior to Nov. 1, 1984), contained 50-
km gridded SST fields. The October 1984 archive tape was the last tape to contain a file
of 500-km fields.

The third file of the 50-km and 500-km tape (second file after October 1984) contained
the 50-km field data for Region 1 from 5N through 53N by -100W through -52W in five
weekly fields organized chronologically. The first physical record of the third file was
the Directory Record which pointed to the beginning of each of the five fields. Each field
had 98 logical records of 2,744 bytes each, blocked into physical records of 10,976 bytes.
There were 491 logical records blocked into 123 physical records in this file. The fourth
and fifth files (third and fourth after October 1984) contained the 50-km gridded fields
for Regions 2 and 3, covered by 15N through 63N by -145W through -97W, and 15N
through 63N by 170E through -142W, respectively. They were identical to the third file
in organization, but differed in the number and size of records in each file. The third file
contained a region with 97 grid intersections per row, one for each .5 degrees of
longitude from -100W eastward to -52W. Similarly, the fourth and fifth files had the
same number of grid intersections per row, but different longitude ranges from -150W to
-70W and 155E to -142W, respectively. The fourth file had five fields with each field
having 62 logical records of 4,536 bytes and the fifth file had 5 fields with each field
having 62 logical records of 3,416 bytes.



                                          5-29          NOAA POD Guide - Jan. 2002 Revision29
Before April 2, 1996, the 50-km gridded SST files were archived to tape twice each
month. Beginning April 2, 1996, these 50 km gridded SST field accumulation files are
archived to tape once a month (on the second day of each month) for the previous month
and the field accumulation files have been enlarged. File 1 remains a header file while
files 2-6 continue to contain the field files. Each field file contains 10 fields (instead of
5) which results in an increase in the number of records in each file. These fields are
produced twice a week by analyzing all the SST observations obtained since the last
analysis. Prior to Aug. 1, 1986, the 50-km gridded fields were generated for three
regions with grid points at every .5 degree latitude/longitude intersection as described
above. After Aug. 1, 1986, they were produced for five regions which are defined in
Table 5.2.1-1.

           Table 5.2.1-1. Areas of 50-km Gridded SST Fields after August 1, 1986.
    Region 1:       5N through 53N latitude
                    -100W through -52W longitude
    Region 2:       15N through 63N latitude
                    -145W through -97W longitude
    Region 3:       15N through 63N latitude
                    +170E through -142W longitude
    Region 4:       -35S through 20N latitude
                    -150W through -70W longitude
    Region 5:       -35S through 20N latitude
                    +155E through -145W longitude

The 50-km gridded SST product (after Aug. 1, 1986) contains six files. The first file is
the Header File, and files 2 through 6 contain 50-km fields for Regions 1 through 5,
respectively. These files are organized in the same manner as the 50-km gridded fields
for three regions as previously described.

Before March 2, 1996, the 100-km SST field has the following structure. There are two
files, the first being the Header File. In File 2, after the Directory Record, there are 20
fields, 142 physical records per field. The Field Documentation Record is followed by
141 Field Data Records, one for each 1 degree latitudinal row from -70S to 70N. There
are 360 grid intersections in each row, one for each l degree of longitude from -180W
eastward to 179E. Currently, each Field Data Record contains 2841 logical records with
a maximum of 30,520 bytes.

Beginning March 2, 1996, the 100-km SST field tape is generated monthly (on the
second day of the month). The tape still contains two files: file 1 is a header file, file 2 is


                                           5-30          NOAA POD Guide - Jan. 2002 Revision30
an archive of the 100-km SST field accumulation file. However, file 2 contains 35 fields,
but continues to have the same file organization as before (i.e., the directory record
structure, the file record length and the format of each field have not changed). Only the
number of fields and therefore the number of records in file 2 has increased.

The 14-km gridded SST fields (Local-Scale Analyses) are archived monthly on two
tapes. There are eight 0.125 degree resolution fields over the areas shown in Table 5.2.1-
2.

                      Table 5.2.1-2. Areas of 14-km Gridded SST Fields
                    18N through 31N latitude
    Region 2:
                    -98W through -80W longitude
                    39N through 52N latitude
    Region 4:
                    -136W through -123W longitude
                    28N through 41N latitude
    Region 5:
                    +114W through -136W longitude
                    30N through 46N latitude
    Region 6:
                    -82W through -60W longitude
                    18N through 32N latitude
    Region 7:
                    -85W through -70W longitude
                    50N through 62N latitude (Seasonal)
   Region 10:
                    -160W through -126W longitude
                    50N through 70N latitude (Seasonal)
   Region 11:
                    -180W through -157W longitude
                    20N through 32N latitude
   Region 12:
                    -136W through -105W longitude

The first tape of the 14-km gridded SST field data contains Regions 2, 4, 5, 6, and 7
which cover the Gulf of Mexico, Northwest Pacific coast, Southwest Pacific coast,
Northeast Atlantic coast, and Southeast Atlantic coast, respectively. This tape contains
six files, the first file being the Header File. The second file contains the 14-km field
data for Region 2. There are twelve weekly fields organized chronologically. The first
record of each field data file is a Directory Record which points to the beginning of each
of the twelve fields. Each field consists of 1273 logical records of 4060 bytes blocked
into 12,180-byte physical records. There are 1,273 logical records blocked into 426
physical records in this file. The third file contains 14-km field data for Region 4. Each


                                         5-31         NOAA POD Guide - Jan. 2002 Revision31
field in the third file consists of 1,273 logical records of 2,968 bytes blocked into 11,872-
byte physical records. There are a total of 1,273 logical records blocked into 321
physical records in the file. The fourth file contains 14-km field data for Region 5. Each
field consists of 1,273 logical records of 4,984 bytes blocked into 9,968-byte physical
records. There are 1,273 logical records blocked into 640 physical records in this file.
The fifth file contains 14-km field data for Region 6. Each field consists of 1,561 logical
records of 4,984 bytes blocked into 9,968-byte physical records. There are a total of
1,561 logical records blocked into 784 physical records in this file. The sixth file contains
14-km field data for Region 7. Each field consists of 1,369 logical records of 3,416 bytes
blocked into 10,248-byte physical records. There are a total of 1,369 logical records
blocked into 460 physical records in this file.

The second tape of the 14-km gridded SST data contains Regions 10, 11 and 12 which
cover the Gulf of Alaska, Bering Sea and the Gulf of California, respectively. This tape
contains four files, the first file being the Header File which has already been described.
The second file contains the 14-km field data for Region 10. This file contains twelve
weekly fields organized chronologically. The first record in each field data file is a
Directory Record which points to the beginning of each of the twelve fields. Each field
consists of 1,177 records of 7,672 bytes each. The third file contains 14-km field data for
Region 11 and has the same format as the second file except each field consists of 1,945
records of 5,208 bytes each. The fourth and file contains 14-km data for Region and is
identical to the second file in organization except the record size is 7,000 bytes.

5.2.1.1            Directory Record Format

A Directory Record is always the first record of each SST Field File (except the Header
File). It has a variable length with zero fill to the logical record size of the type of field,
and serves as a pointer to the beginning of each field. Table 5.2.1.1-1 contains the format
of the Directory Record.
                Table 5.2.1.1-1. Format of the Directory Record for the SST Field File.
 Full Word #                                             Content
          1          Number of records in the data set
          2          Number of records in each field (NRECS)
          3          Number of fields in the accumulation file (NFIELDS)
          4          Field number of latest field entered in accumulation file
          5          Record number of first record of Field #1
          6          Record number of first record of Field #2
          ...        ...
 4+NFIELDS           Record number of first record of Field # NFIELDS




                                             5-32         NOAA POD Guide - Jan. 2002 Revision32
5.2.1.2       Field Documentation Record

The format of the Field Documentation Record is described in Table 5.2.1.2-1. There are
158 words of information in the Field Documentation Record with blank fill to the logical
record size of the particular kind of field. The minimum size is 158 words (632 bytes)
and the maximum size is 2,527 words (10,108 bytes). It has the following format (where
R or I indicates real or integer words, respectively):
                  Table 5.2.1.2-1. Format of the Field Documentation Record.
 Word #     Parameter     R      Description
                          or I
 1          LDBGN         I      Record number of the first row of the field (currently 2 for all
                                 fields since the documentation record requires only one
                                 record).
 2          SMGLAT        R      Minimum latitude included in field which is the bottom edge
                                 and first row of field (-South; + North).
 3          AXLAT         R      Maximum latitude included in field which is the top edge and
                                 last row of field (-South; + North).
 4          SMLONG        R      Minimum longitude included in field which is the left edge and
                                 first column of field (-West; + East).
 5          AXLONG        R      Maximum longitude included in field which is the right edge
                                 and last column of field (excluding the I.D. column) (-
                                 West;+East).
 6          RES           R      Number of latitude-longitude degrees between each grid point.
 7          SMHOUR        R      Youngest time, in hours of the year, of observations used
                                 during last analysis, which becomes the oldest time allowed for
                                 the next analysis.
 8          HOURS         R      Oldest time, in hours of the year, of observations used during
                                 last analysis.
 9          TIMGAP        R      Number of hours between youngest and oldest times of
                                 observations used in analysis.
 10         MAXDAT        I      Maximum number of hours allowed in time period for
                                 observation times to be included in analysis.
 11         SMREL         R      Minimum reliability of observations to be used in analysis.
 12         AXREL         R      Maximum reliability of observations to be used in analysis.
 13-22      SORC(10)      R      List of source codes of observations to be used in analysis.
                                 (See Table 5.2.2.1-6)




                                         5-33         NOAA POD Guide - Jan. 2002 Revision33
23-32   OBTYPE     R   List of observation types allowed to be used in analysis. (See
        (10)           Table 5.2.2.1-5)
33      NROWS      I   Number of rows (latitudinal parallels) included in field,
                       excluding documentation record.
34      NCOLS      I   Number of columns (longitudinal meridians) in field, including
                       the I.D. column.
35      IBLK       I   Number of rows or logical records per physical block.
36      NWRDS      I   Number of full words (32 bits) allocated to each grid point.
37      ISZ        I   Number of rows to be maintained in an array in core for
                       temperature analysis and calculation of gradients.
38      ICENT      I   Center line within the array of ISZ rows upon which
                       calculations will be performed.
39-41   LWT,       I   Word number, length in bits, and starting bit location of
        LNT, LBT       analysis temperature within a grid intersection information unit
                       of an SST field.
42-44   LWG,       I   Word number, length in bits, and starting bit location of
        LNG,LBG        average gradient.
45-47   LWGXP,     I   Word number, length in bits, and starting LBGXP bit location
        LNGXP,         of gradient X+ direction.
        LBGXP
48-50   LWGXN,     I   Word number, length of bits, and starting LBGXN bit
        LNGXN,         location of gradient X- direction.
        LBGXN
51-53   LWGYP,     I   Word number, length in bits, and starting LBGYP bit location
        LNGYP,         of gradient Y+ direction.
        LBGYP
54-56   LWGYN,     I   Word number, length in bits, and starting LBGYN bit location
        LNGYN,         of gradient Y- direction.
        LBGYN
57-59   LWPD,      I   Word number, length in bits, and starting LBPD bit location of
        LNPD,          Physiographic Description.
        LBPD
60-62   LWNO,      I   Word number, length in bits, and starting LBNO bit location
        LNNO,          of Number Observations.
        LBNO




                               5-34         NOAA POD Guide - Jan. 2002 Revision34
63-65     LWAGE,    I   Word number, length in bits, and starting LBAGE bit location
          LNAGE,        of Age of most Recent Observations.
          LBAGE
66-68     LWREL,    I   Word number, length in bits, and starting LBREL bit location
          LNREL,        of Reliability.
          LBREL
69-71     LWCLS,    I   Word number, length in bits, and starting LBCLS bit location
          LNCLS,        of Class 1 coverage.
          LBCLS
72-74     LWSXP,    I   Word number, length in bits, and starting LBSXP bit location
          LNSXP,        of Spatial Covariance X+.
          LBSXP
75-77     LWSXN,    I   Word number, length in bits, and starting LBSXN bit location
          LNSXN,        of Spatial Covariance X-.
          LBSXN
78-80     LWSYP,    I   Word number, length in bits, and starting LBSYP bit location
          LNSYP,        of Spatial Covariance Y+.
          LBSYP
81-83     LWSYN,    I   Word number, length of bits, and starting LBSYN bit location
          LNSYN,        of Spatial Covariance Y-.
          LBSYN
84-86     LWIND,    I   Word number, length in bits, and starting LBIND bit location
          LNIND,        of Independent Temperature.
          LBIND
87-96     GRDWTS    R   Weight assigned to each grid unit, according to its distance
          (10)          from the grid intersection for which gradients are being
                        calculated.
97        NP        I   Number of grid points to be used in calculation of gradients.
98-117    KMDST     I   Look up table of gradient values and corresponding distances
          (10,2)        to be used in determining the search area for analysis.
118       MKM       R   Number of paired entries in KMDST.
119-138   H(10,2)   R   Look up table of gradient values and corresponding factors to
                        be used in determining the new weight assigned to the
                        observation temperature analysis.
139       MH        I   Number of paired entries in H.
140       EXP       R   Exponent used in temperature analysis.




                                5-35         NOAA POD Guide - Jan. 2002 Revision35
141   FDX      R   Factor used in determining new weight assigned to the
                   observation temperature for analysis.
142   XCLASS   R   Factor used to place gradients into a class for Gradient Class
                   Summary.
143   DEL      R   Maximum number of degrees Centigrade (x 10) that the new
                   analysis temperature may differ from the previous SST field
                   temperature.
144   MF       I   Factor applied to the previous field temperature and reliability
                   to determine the final analysis temperature and its reliability.
145   MSTAR    I   Factor applied to the combined observation temperature and
                   weight in determining the new analysis temperature.
146   MNSRCH   I   Minimum distance in kilometers to be searched for analysis
                   observations.
147   MXSRCH   I   Maximum distance in kilometers to be searched for analysis
                   observations.
148   BDEL     R   Maximum distance in kilometers to be searched for analysis
                   observations. Maximum difference allowed between new
                   analysis temperature and the previous one for Class 1 coverage
                   bit to be set to 1.
149   FCWT     R   Maximum value that can be assigned as the reliability of the
                   new analysis temperature.
150   IYYY     I   Year of youngest time of observation data used (0-99).
151   IYMM     I   Month of youngest time of observation data used (1-12).
152   IYDD     I   Day of youngest time of observation data used (1-31).
153   IYHH     I   Hour of youngest time of observation data used (0-23).
154   IOYY     I   Year of oldest time of observation data used (0-99).
155   IOMM     I   Month of oldest time of observation data used (1-12).
156   IODD     I   Day of oldest time of observation data used (1-31).
157   IOHH     I   Hour of oldest time of observation data used (0-23).
158   ICURTM   I   Last time used in analysis (in Julian days from Jan. 1, 4713
                   BC).




                           5-36         NOAA POD Guide - Jan. 2002 Revision36
5.2.1.3        Field Data Record Format

Each Field Data Record (latitudinal row) consists of a series of grid intersection points.
These points are 28 bytes in length. Each longitude (column) reflects one grid
intersection. At the end of the data record (i.e., immediately following the last column) is
the 28-byte Latitudinal Row Identifier. All parameters in the grid intersection are stored
as integer values and have the format shown in Table 5.2.1.3-1. Note: climatology values
are available in global SST fields only.

             Table 5.2.1.3-1. Format of the Parameters in the Grid Intersection.
 Word #     Byte #                  Description                  Units                Range
     1        1-2     Analysis Temperature                       C x 10            -850 to +610
     1        3-4     Average Gradient                      C/100 km (x 10)          0 to 300
     2        5-6     Gradient X+                           C/100 km (x 10)          0 to 300
     2        7-8     Gradient X-                           C/100 km (x 10)          0 to 300
     3       9-10     Gradient Y+                           C/100 km (x 10)          0 to 300
     3       11-12    Gradient Y-                           C/100 km (x 10)          0 to 300
     4         13     Physiographic Descriptor              0 = sea; 1=land           0 to 15
     4         14     Spare                                    Undefined              Blank
     4         15     Number of Observations                     Integer             0 to 255
     4         16     Age Recent Observations                    Hours               0 to 255
     5       17-18    Reliability                                Integer            0 to 32767
     5       19-20    Class 1 Coverage                            Bits                0 or 1
     6         21     Spatial Covariance X+                    Grid units             0 to 10
     6         22     Spatial Covariance X-                    Grid units             0 to 10
     6         23     Spatial Covariance Y+                    Grid units             0 to 10
     6         24     Spatial Covariance Y-                    Grid units             0 to 10
     7       25-26    Climatological Temperature                C (x 10)           -850 to +610
     7       27-28    Spare                                    Undefined              Blank

The format of the Latitudinal Row Identifier (last 28 bytes of a row) is contained in Table
5.2.1.3-2. All parameters in the table are stored as integer values. Words 5 through 7 are
the date and time at which analysis was performed.



                                            5-37       NOAA POD Guide - Jan. 2002 Revision37
                  Table 5.2.1.3-2. Format of the Latitudinal Row Identifier
  Word #      # Bytes              Description                    Units               Range
     1           4       Row                                      Integer             1-141
     2           4       Spare                                  Undefined            0 to 232
     3           4       Spare                                  Undefined            0 to 232
     4           1       Physiographic Descriptor                 Integer          Always 255
     4           3       Spare                                  Undefined            0 to 224
                        Date and time at which analysis was performed:
     5           4       Hour of Day, Minutes of hour         100 x hours +       100 x (0-23) +
                                                                minutes               (0-59)
     6           4       Day of Year                               Days               1-366
     7           4       Year (2-digit)                           Years                0-99

The terms used to describe the grid intersection points are defined as follows:

ANALYSIS TEMPERATURE - The latest sea surface temperature calculated based on
the previous analysis temperature, weighted according to its reliability combined with a
weighted average of current observations within a surrounding area which is determined
according to the grid points gradient.

AVERAGE GRADIENT - The average of the gradients in all four directions (N, S, E, W)
from the grid intersection.

GRADIENT IN X+ DIRECTION - Change in temperature between the grid point and
neighbor points within the field in the positive direction along the X axis.

GRADIENT IN X- DIRECTION - Change in temperature in the negative direction along
the X axis.

GRADIENT IN Y+ DIRECTION - Change in temperature in the positive direction along
the Y axis.

GRADIENT IN Y- DIRECTION - Change in temperature in the negative direction along
the Y axis.

PHYSIOGRAPHIC DESCRIPTOR - The land/sea tag indicating whether a grid
intersection is a land or sea point.

SPARE - Unused parameter.



                                          5-38         NOAA POD Guide - Jan. 2002 Revision38
NUMBER OF OBSERVATIONS - The total number of current observations used in the
analysis of the new temperature for the grid intersection.

AGE OF MOST RECENT OBSERVATION - The age, in hours from the time of last
analysis, of the most recent observation used to determine the new temperature for a grid
intersection.

RELIABILITY - New reliability associated with the new temperature, based on the
previous reliability combined with the weighted reliability of all observations used in the
last analysis. Larger values are more reliable.

CLASS 1 TEMPORAL COVERAGE - Set of bits (0-15) of which Bit 1 is set to 1 for
each analysis which included observations with a reliability greater than or equal to a
specific minimum reliability considered as Class 1. Bit 0 always remains a 0, and all bits
are shifted right during each analysis leaving Bit 1 to 0 when no Class 1 reliability
observations are used for a grid intersection.

SPATIAL COVARIANCE X+ - The distance in grid units from the grid intersection to
the nearest land mass in the positive direction along the X axis.

SPATIAL COVARIANCE X- - The distance in grid units from the grid intersection to
the nearest land mass in the negative direction along the X axis.

SPATIAL COVARIANCE Y+ - The distance in grid units from the grid intersection to
the nearest land mass in the positive direction along the Y axis.

SPATIAL COVARIANCE Y- - The distance in grid units from the grid intersection to
the nearest land mass in the negative direction along the Y axis.

CLIMATOLOGICAL GRID TEMPERATURE - The average sea surface temperature of
a grid intersection for a particular month over a number of years, taken from the global
climatology file (for global field files only).

5.2.2          SST Observation File

There has been a steady evolution of the SST Observation file since it was first generated
in December 1978 using TIROS-N data. In 1978, the SST Observation file contained
seven days of SST data at a resolution of 50 km. On Nov. 17, 1981, the operational
technique for calculating SSTs was changed to a multichannel technique with separate
algorithms for day and night observations. This new multichannel technique yielded a
much improved resolution of 8 km. On Nov. 1, 1986, the SST Observation File was
changed to eight days to satisfy requirements for the Tropical Ocean and Global
Atmosphere (TOGA) project. The basic structure of the two types of SST Observation
Files is very similar. However, there are differences in the format of the Block Directory,
Subblock Directory, and the Observation Unit. Section 5.2.2.1 describes the Seven Day
Observation File and Section 5.2.2.2 describes the Eight Day Observation File.



                                          5-39         NOAA POD Guide - Jan. 2002 Revision39
The SST Observation File contains either seven or eight days of SST observations
(depending on time period of data) which are organized in 5 x 5 degree blocks. These 5 x
5 degree blocks are further subdivided into 1 x 1 degree subblocks. Global coverage
requires 2,592 blocks. The block number IBLOCK for an observation located at ILAT
latitude (+N,-S) and ILONG longitude (+E,-W) can be calculated using the following
equation:

                              ( ILAT  LA)          ( ILONG  LO)
                 IBLOCK                    INBC                1                 5.2.2-1
                                  LAO                    LOO

where LA is the latitude origin of the file (-90 degrees), LO is the longitude origin of the
file (-180 degrees), LAO is the size of the block in the latitudinal direction (5 degrees),
LOO is the size of the block in the longitudinal direction (5 degrees), and INBC is the
number of column blocks (360 degrees/LOO). Each block includes the minimum whole
latitude and longitude, and excludes the maximum whole latitude and longitude which
borders the block. For example, the limits of Block 1 are: -90.0S to -85.01S and -
180.0W to -175.01W. Since all subblocks are 1 degree boxes, the Subblock number SBN
for a given latitude and longitude can be defined as:

                        SBN  ( ILAT  LLA)  ILONG  LLL  1                        5.2.2-2

where LLA and LLL are respectively the lower left latitude and longitude of the 5 degree
block.

On July 26, 1995, NESDIS began archiving an 8-day observation file created from SST
retrievals processed at the Naval Oceanographic Center at Stennis Space Center, MS.
This was initiated under a Department of Commerce/Department of Defense agreement
for shared processing. This file is identical in format to the NESDIS 8-day observation
file.

5.2.2.1        Seven Day SST Observation File

The Seven Day SST Observation File is organized with the first record containing
documentation and directory information. This Block Directory Record points to the
location of the beginning record for each block in the file. The first record in each block
contains a Subblock directory. The Subblock Directories point to the first Observation
Unit (6 words) in each of 25 subblocks for each block. The structure of the SST
Observation File is shown in Figure 5.2.2.1-1.




                                          5-40         NOAA POD Guide - Jan. 2002 Revision40
           Figure 5.2.2.1-1 Structure of the Seven Day SST Observation File

The first record in the SST Observation File is the Block Directory and it contains 13,024
bytes. The Block Directory contains location information, dates of data, and pointers to
the location of the beginning record for each block. The format of the Block Directory
for the Seven Day SST Observation File is contained in Table 5.2.2.1-1.

 Table 5.2.2.1-1. Format of the Block Directory for the Seven Day SST Observation File.
 Halfword #                                             Contents
       1         LA, the latitude origin of the file
       2         LO, the longitude origin of the file
       3         LAO, size of block in latitudinal direction
       4         LOO, size of block in longitudinal direction
       5         First free record pointer
       6         Number of records in file
       7         Start of Block Directory Information (in halfwords)
       8         Day of year of most recent information
       9         Year of most recent information
      10         NESDIS archive flag (1 if archived; 0 if not archived) of most recent
                 information



                                             5-41        NOAA POD Guide - Jan. 2002 Revision41
    11-13       Day of year, year, NESDIS flag of 2nd most recent data
    14-16       Day of year, year, NESDIS flag of 3rd most recent data
    17-19       Day of year, year, NESDIS flag of 4th most recent data
    20-22       Day of year, year, NESDIS flag of 5th most recent data
    23-25       Day of year, year, NESDIS flag of 6th most recent data
    26-28       Day of year, year, NESDIS flag of 7th most recent data
    29-31       Day of year, year, NESDIS flag of 8th most recent data
    32-40       Unused
      41        Record position for block 1 (zero if no data in block)
      42        Record position for block 2 (zero if no data in block)
      ...       ...

Under normal circumstances, there can be a maximum of 3,250 blocks. The remaining
records in the SST Observation File contain the Subblock Directories and Observation
Units. The format for the Subblock Directory is contained in Table 5.2.2.1-2.

                      Table 5.2.2.1-2. Format of the Subblock Directory
                         Halfword #       Byte #                         Contents
                              1                1      Record number
                              2                3      Block number
                              3                5      Pointer (in halfwords) to start position of
                                                      Subblock directory information
                              4                7      Length of observation unit in words
                                                      (normally 6 words)
                              5                9      LLA, lower left latitude of block
                              6             11        LLL, lower left longitude of block
                              7             13        Pointer (in halfwords) for start of
                                                      observation data
                              8             15        Unused
                              9             17        Position (in halfwords) for start of
                                                      Subblock 1 Observation Units




                                        5-42         NOAA POD Guide - Jan. 2002 Revision42
  Repeated for rest of          10             19         Position for end of Subblock 1
      Subblocks                                           Observation Units
                                11             21         Record number containing Subblock 1
            ...                 ...                ...    ...

There is only one Subblock Directory for each block. It is not repeated at the start of
each new record. If no data is contained in a Subblock, then all corresponding location
parameters are set to zero. All unused bytes in each record are set to zero.

The Observation Unit contains the actual SST data for each Subblock. Each unit contains
6 words and has the format shown in Table 5.2.2.1-3. The first bit in the Observation
Unit must be on as this signifies the beginning of the unit. Thus, the type of observation
is coded in one byte as a number between 129 and 255. Also, there cannot be a high
order bit on in any odd full word of the unit because it will be interpreted as the
beginning of a unit. Note: in this format a longitude value of +180 degrees is not allowed
and a value of -3000 for temperature signifies no information.

                         Table 5.2.2.1-3. Format of the Observation Unit.
 Halfword #       Byte #                            Content                           Range
       1            1         Type of observation (see Table 5.2.2.1-5)              129-255
       1            2         Source of observation (see Table 5.2.2.1-6)              0-255
       2            3         Year of century (last 2 digits)                          0-99
       2            4         Month of year                                            1-12
       3           5-6        Latitude (+N, -S) x 100                              -9000 to 9000
       4           7-8        Longitude (+E, -W) x 100                           -18000 to 17999
       5            9         Day of month                                             1-31
       5            10        Hour                                                     0-23
       6            11        Minute                                                   0-59
       6            12        Second                                                   0-59
       7          13-14       SST Measurement (degrees C x 10)                     -3000 to 1000
       8          15-16       Reliability                                            Variable
                                                                                   (normal=100)
     9-12         17-24       Variable information (depending on                        n/a
                              observation type)




                                            5-43          NOAA POD Guide - Jan. 2002 Revision43
The record structure of the Seven Day SST Observation File is contained in Table
5.2.2.1-4 (assuming that data for 25 subblocks can be stored in one record). If there are
no data in a block, there will be no record for that block. If there are numerous data for a
block, there will be more than one consecutive record allocated to that block. Note:
Currently, the SST Observation File has a maximum of 4,002 records.

         Table 5.2.2.1-4. Record structure of the Seven Day SST Observation File.
      Record #                                          Contents
          1            Block Directory
          2            1st block, Subblock directory and data for 25 subblocks
          3            2nd block, Subblock directory and data for 25 subblocks
          ...          ...
        2593           2592nd block, Subblock directory and data for 25 subblocks

Tables 5.2.2.1-5 and 5.2.2.1-6 contain the SST Observation types and source codes,
respectively.

                             Table 5.2.2.1-5. SST Observation Types.
       Code                                              Type
         0           No type
       1-128         Illegal type code
        129          Nominal SST
        130          AVHRR only SST
        131          HIRS/2 only SST
        132          Coastal type
        133          Reserved
        134          Reserved
        135          Reserved
        136          Reserved
        137          Reserved
        138          Test type
     139-149         Reserved



                                          5-44         NOAA POD Guide - Jan. 2002 Revision44
      150          Heat Budget observation
      151          AVHRR-only day operational
      152          AVHRR-only night operational
      153          HIRS-only day operational
      154          HIRS-only night operational
      155          AVHRR + HIRS day operational
      156          AVHRR + HIRS night operational
      157          Reserved
      158          Aerosol contaminated night operational
      159          Reserved
      160          Reserved
      161          AVHRR-only day test
      162          AVHRR-only night test
      163          HIRS-only day test
      164          HIRS-only night test
      165          AVHRR + HIRS day test
      166          AVHRR + HIRS night test
    167-168        Reserved
      179          ITOS SST
    180-199        Reserved
      200          Independent SST (Ship or Buoy)
    201-254        Reserved
      255          Erroneous Data - Do not use this Observation
Note: Codes having values between 0 and 149 (inclusive) indicate the operational technique in
use between Dec. 1, 1978 and Nov. 16, 1981. Codes having values between 150 and 166
(inclusive) indicate a multichannel technique in use between Nov. 17, 1981 and the present.




                                        5-45        NOAA POD Guide - Jan. 2002 Revision45
                      Table 5.2.2.1-6. SST Observation Source Codes
     Source code                                      Source
    (archived data)
         128               No source
         129               AVHRR #1 (TIROS-N)
         130               AVHRR #2 (NOAA-6)
         131               AVHRR #3 Not used
         132               AVHRR #4 (NOAA-7)
         133               AVHRR #5 Not used
         134               AVHRR #6 (NOAA-8) 1
        135, 72            AVHRR #7 (NOAA-9)
           8               AVHRR #8 (NOAA-10) 1
           1               AVHRR #9 (NOAA-11)
           5               AVHRR #10 (NOAA-12)
           2               AVHRR #11 (NOAA-13) 3
           3               AVHRR #12 (NOAA-14)
         TBD               AVHRR #15-20 (TBD)
         21-50             ITOS NOAA-1 Sensor #1
          51               ITOS NOAA-1 Sensor #2
          53               ITOS NOAA-2 Sensor #1
          54               ITOS NOAA-2 Sensor #2
         55-58             ITOS NOAA-3 and -4
         59-62             ITOS NOAA-5
        63-127             Reserved
1
  No SSTs were archived for these satellites.
2
  NOAA-9 source code was 135 prior to August 4, 1986. NOAA-9 source code was 7
beginning on August 4, 1986.
3
  No SSTs were ever produced for this satellite.




                                       5-46      NOAA POD Guide - Jan. 2002 Revision46
5.2.2.2         Eight Day SST Observation

The Eight Day SST Observation File is arranged similarly to the Seven Day Observation
File (see Fig. 5.2.2.1-1). Currently, it has 5 x 5 degree blocks, which are further
subdivided into 1 x 1 degree subblocks. There are 25 subblocks in each block. The first
record in the Eight Day SST Observation File is the Block Directory which contains
13,028 bytes using the record format VS option. The format of the Block Directory is
contained in Table 5.2.2.2-1.

                       Table 5.2.2.2-1. Format of the Block Directory Record.
 Halfword #                                           Contents
          1      LA, the latitude origin of the file (range: -90 to 90)
          2      LO, the longitude origin of the file (range: -180 to 180)
          3      LAO, size of block in latitudinal direction (range: 1 to +5)
          4      LOO, size of block in longitudinal direction (range: 1 to +5)
          5      First free record pointer (points to record number of 1st record available as an
                 overflow track; 0 if no more tracks available).
          6      Number of records in file (3100 initially)
          7      Start of Block Directory Information in halfwords (11 initially)
          8      Day of year of most recent information (range: 1 to 366)
          9      File availability: 0=available; 1=unavailable, update in progress
      10         Year of century of last data (range: 0 to 99)
      11         Record number for Block 1 (range: 2 to 3100; 0 for no data in block)
      12         Record number for Block 2 (range: 2 to 3100; 0 for no data in block)
          ...    ...

Using the block number, the record number can be calculated and found in the portion of
the Block Directory which serves as a lookup table. If the record number entry is zero,
there is no data for that corresponding block in the file. The record number points to the
Observation Data record, of which the first portion is a subdirectory. The file contains
8,446 records of 13,028 bytes each. The Observation Data record has the format shown
in Table 5.2.2.2-2.




                                           5-47         NOAA POD Guide - Jan. 2002 Revision47
                    Table 5.2.2.2-2. Format of Observation Data Record
 Halfword #                              Contents                                   Range
       1        Record number                                                      2 to 4002
       2        Block number                                                       1 to 2592
       3        Extent number (number of records removed from                    0 (if primary)
                primary)
       4        Pointer to succeeding overflow record. Last overflow           0 if no overflow
                record points to primary record.
       5        Pointer to halfword position of start of Observation Unit             61
       6        Pointer to start of Subblock Directory                                11
       7        Lower left latitude of block LLA (+N,-S) in degrees               -90 to +90
       8        Lower left longitude of block LLL (+E,-W) in degrees             -180 to +180
       9        Pointer to last halfword containing data                              n/a
      10        Unused                                                                n/a
      11        Halfword of start of data for Subblock #1                         0 if no data
      12        Halfword of end of data for Subblock #1 (other extents            0 if no data
                may or may not contain data for this Subblock).
    13-60       Similar to halfwords # 11 and #12 for remaining                       n/a
                subblocks
   61-6512      Observation Unit                                                      n/a

If the block size is changed in the future, a block may contain a different number of
subblocks, thus changing the number of Subblock pointers and the starting halfword of
the Observation Unit. If the observations for a block do not fit on one record, then as
many records (extents) are allocated as needed. Each additional record will include the
subdirectory and Observation Unit. If the Subblock contains no information, then the
start and end position contain a zero. Subblocks may cross record boundaries. If an
entire Subblock cannot fit into one record, it will be split and a new record will be
allocated for the remainder of the Subblock. Unused portions of records and records
containing no data will be zero filled.

The Observation Unit for the Eight Day SST Observation File is of variable length,
ranging from a minimum of 4 words to a maximum of 24 words. The length must be an
even number of full words with no odd full word (except the first word which is always
negative). The first three words of an Observation Unit contain identification
information including the type of algorithm used, the satellite, date, time, and location.



                                          5-48         NOAA POD Guide - Jan. 2002 Revision48
The fourth word contains the actual SST data and the reliability assigned to the
observation. The remainder of the Observation Unit is unique to the type of algorithm
used. The format of the Eight Day SST Observation Unit is contained in Table 5.2.2.2-3.

              Table 5.2.2.2-3. Format of the Eight Day SST Observation Unit.
 Halfword #     Byte #                         Contents                            Range
      1            1     Type of Observation (Table 5.2.2.1-5)                   129 to 255
      1            2     Source of Observation (Table 5.2.2.1-6)                   0 to 255
      2            3     Year                                                      0 to 99
      2            4     Month                                                     1 to 12
      3           5-6    Latitude (+N,-S) x 100                                 -9000 to 9000
      4           7-8    Longitude (+E, -W) x 100                                 -18000 to
                                                                                    17999
      5            9     Day                                                       1 to 31
      5           10     Hour                                                      0 to 23
      6           11     Minute                                                    0 to 59
      6           12     Second                                                    0 to 59
      7         13-14    SST (degrees C x 10)                                     -20 to 350
      8         15-16    Reliability                                             0 to 32767
      9         17-18    Solar Zenith Angle (degrees x 10)                        0 to 1800
      10        19-20    Satellite Zenith Angle (degrees x 100)                  -600 to 600
      11        21-22    Analyzed Field SST (degrees C x 10)                      -20 to 350
      12        23-24    Internal Error (RMS x 100)                               0 to 1000
      13        25-26    Solar azimuth angle (degrees x 10)                       0 to 1800
      14        27-28    Climatological SST (degrees C x 10)                      -20 to 350
      15          29     Beginning Row if unit array                               1 to 11
      15          30     Beginning Column of unit array                            1 to 11
      16        31-32    AVHRR Channel 1 average (% x 100)                       0 to 10000
      17        33-34    AVHRR Channel 2 average (% x 100)                       0 to 10000
      18        35-36    AVHRR Channel 3 average (K x 100)                       0 to 32767



                                        5-49        NOAA POD Guide - Jan. 2002 Revision49
      19          37-38    AVHRR Channel 4 average (K x 100)                          0 to 32767
      20          39-40    AVHRR Channel 5 average (K x 100)                          0 to 32767
      21          41-42    Space view σ Channel 1 (% x 100)                           0 to 10000
      22          43-44    Space view σ Channel 2 (% x 100)                           0 to 10000
      23          45-46    Space view σ Channel 3 (K x 100)                           0 to 32767
      24          47-48    Channel 4 Blackbody Temperature (K x 100)                  0 to 32767
      25          49-50    Channel 5 Blackbody Temperature (K x 100)                  0 to 32767
      26          51-52    Year of observation1                                     1998 to 32767
      27          53-56    Spares                                                            n/a
 1
    This change makes the software Year 2000 compliant with a 4-digit year. Change went into
 effect on 4/29/98 with the 12Z NOAA-14 GAC orbit.

5.2.3           SST Monthly Mean Archive
The SST Monthly Mean Archive contains 12 monthly mean SST fields for one year.
NESDIS creates this archive tape in January of every year, archiving the monthly mean
fields for the previous year. The data on this tape were derived exclusively from satellite
data. The field has a 2.5 degree latitude-longitude resolution or 250-km resolution. For
each 2.5 degree box in the field, there is a count of the number of observations in the box,
the mean SST, and the standard deviation about the mean, σ.

The SST Monthly Mean archive tape contains two files. The first file is a Header File
(previously described in Section 5.2) which contains information about the data on tape.
The second file has 72 physical records, each containing 12 logical records consisting of
satellite SST monthly mean data. For each month of the year and for each point of its
geographical grid, the data consists of 1) the month's mean temperature, T; 2) the
standard deviation of a single measure, σT ; and 3) the number of observations entering
into the mean, N. Each of these quantities are stored as 2-byte integers: T as degrees C x
10, σT as degrees C x 100 and N as itself.

The geographical grid establishes a global field of boxes at 2.5 degree resolution. Boxes
are bordered by meridians and parallels which are multiples of 2.5 degrees in latitude and
longitude. Four of these boxes can be combined to produce boxes centered on
intersections of meridians and parallels which are multiples of 5 degrees in latitude and
longitude.

The second file contains 12 fields, the first is January, the last is December. Each field
has 72 logical records grouped into 12 logical records per physical record or each field
has 6 physical records. Each logical record is 876 bytes long with 10,512 bytes in a
physical record. The first logical record in each field contains data for the 2.5 degree
latitude band with southern boundary at 90.0S. The 72nd logical record for a field has


                                          5-50         NOAA POD Guide - Jan. 2002 Revision50
data for the 2.5 degree latitude band with southern boundary at 87.5N. Within a latitude
band, the first grid box has a westernmost boundary of 180W. The 144th grid box has a
westernmost boundary of 177.5E. Each grid box requires three 16-bit halfwords. In
addition, the first 12 bytes of each logical record contains the year, month, and latitude of
the latitude band. A detailed format description of a Monthly Mean Data Field is
contained in Table 5.2.3-1.

                        Table 5.2.3-1. Format of Monthly Mean Data Field
 Logical        Bytes                         Content (Integer values indicated)
 Record #
     1           1-4       Year of data (e.g., 1978)
      1          5-8       Month of data (e.g., 1)
      1          9-12      Latitude of southern edge of this 2.5 degree latitude band (real value)
      1         13-14      Number of observations N for 2.5 degree box with southwest corner at
                           90.0S, 180.0W.
      1         15-16      Monthly mean temperature T (degrees C x 10) for same box
      1         17-18      Standard deviation σT (degrees C x 100) for same box
      1         19-20      N for 2.5 degree box with southwest corner at 90.0S, 177.5W.
      1         21-22      T for same box
      1         23-24      σT for same box
     ...          ...      ...
      1        871-872     N for 2.5 degree box with southwest corner at 90.0S, 177.5E.
      1        873-874     T for same box
      1        875-876     σT for same box
     ...          ...      ...
     72        10,507-     N for 2.5 degree box with southwest corner at 87.5N, 177.5E.
               10,508
     72        10,509-     T for same box.
               10,510
     72        10,511-     σT for same box.
               10,512




                                             5-51       NOAA POD Guide - Jan. 2002 Revision51
5.3              Mapped GAC Products

The mapped GAC products consist of mapped mosaics displayed on Polar Stereographic
and Mercator map projections with both forms available on CCTs. The mapped mosaics
are of daytime visible (VIS) and Infrared (IR), and nighttime IR imagery. The mapped
GAC product in Polar Stereographic form is described in Section 5.3.1, while the mapped
GAC product in Mercator form is described in Section 5.3.2.

NESDIS/IPD produces an operational mapped GAC product which is known as the
Global Vegetation Index Product. This product provides a means of monitoring the
density and vigor of green vegetation over the growing areas of the Earth. Plate Carrée,
Polar Stereographic and Mercator mosaics of the Global Vegetation Index, derived from
AVHRR Channels 1, 2, plus coincident channels 4 and 5, and supporting information are
produced weekly. For more information, contact NCDC to obtain a copy of the NOAA
Global Vegetation Index User'sGuide.

5.3.1            Mapped GAC (Polar Stereographic) Product (1979 - Oct. 26, 1994)

Mapped GAC Product (in Polar Stereographic projection) produced between 1979 and
Oct. 26, 1994 have the format described in this section. The mapped mosaics are
displayed on a 1024 x 1024 Polar Stereographic grid that provides 14.8 km resolution at
the Equator decreasing to 29.6 km near the poles. The mapped GAC (Polar
Stereographic) product tapes have the file structure as shown in Table 5.3.1-1.

          Table 5.3.1-1. File Structure of the Mapped GAC (Polar Stereographic) Tapes.
 File #      Record #   Bytes/                            Contents
                        record
      1         1        4096    Northern Hemisphere IR day documentation
                2        4096    Northern Hemisphere VIS day documentation
      2       1-512      4096    Northern Hemisphere IR/VIS day data (interleaved)
      3         1        4096    Southern Hemisphere IR day documentation
                2        4096    Southern Hemisphere VIS documentation
      4       1-512      4096    Southern Hemisphere IR/VIS day data (interleaved)
      5         1        4096    Northern Hemisphere IR night documentation
      6       1-256      4096    Northern Hemisphere IR night data
      7         1        4096    Southern Hemisphere IR night documentation
      8       1-256      4096    Southern Hemisphere IR night data




                                         5-52        NOAA POD Guide - Jan. 2002 Revision52
Files 2 and 4 contain IR and VIS data for both hemispheres. The 8-bit IR daytime and 8-
bit VIS mapped quantities are combined into a single 16-bit quantity for each map
position. The upper order 8 bits are the IR day data and the lower order 8 bits are the VIS
data. This 16-bit combination gives the user a comparison of identical time views with
IR and VIS data for each grid position. Each data record contains 4,096 (8-bit) bytes
which holds two mapped rows. Temperature values range from 0 (warm) to 254 (cold)
for IR data, and a brightness count from 0 (dark) to 254 (bright) for VIS data. A value of
255 represents no data. Figure 5.3.1-1 shows the
arrangement of the data on the Polar Stereographic map base for IR day and VIS.

The format for Files 6 and 8 (which contain IR night data for both hemispheres) is similar
to Files 2 and 4 except that there is only one type of data represented. Each record
contains 4,096 bytes which correspond to four map rows. Each byte represents a mapped
value ranging from 0 (warm) to 254 (cold). Figure 5.3.1-2 shows the arrangement of the
data on the Polar Stereographic map base for IR night.




Figure 5.3.1-1. Arrangement of IR Day and VIS Data on Polar Stereographic Map.


                                         5-53         NOAA POD Guide - Jan. 2002 Revision53
Files 1, 3, 5, and 7 contain documentation for the data file immediately following. These
documentation files contain a single 4,096 word (32-bit) record. The documentation
record of each map file contains a 32-word documentation group for each of the passes
mapped for a single day's archive. The first word of the record indicates the number of
passes processed. The format of the documentation record is contained in Table 5.3.1-2.
The time information is contained in the rightmost six-bytes of the specified two-word
group. The time consists of the year, Julian day, and time of day (UTC) in milliseconds.
The year is contained in the first seven bits of the first two bytes, with the nine-bit Julian
day right justified in the same two bytes and the 27-bit millisecond time of day right
justified in the last four bytes. All other bits are set to zero.

                     Table 5.3.1-2. Format of the Documentation Record.
        Word #                                             Content
           1              Number of data sets processed
           N              Spacecraft ID (See Section 2.0.1)
          N+1             Spare
      N+2 to N+3          Data set start time
          N+4             Spare
      N+5 to N+6          Data set end time
          N+7             Spare
      N+8 to N+9          Processing block ID (See Section 2.0.1)
         N+10             Spare
         N+11             Data type (GAC data=32)
    N+12 to N+31          Spares
                Note: Word numbers N through N+31 are repeated for each data set.

The processing block ID is written in ASCII character code. The conversion table for
hex to ASCII is included in Table 2.1.1-2.

It is helpful when working with Polar Stereographic maps to be able to convert from
latitude and longitude to I and j coordinates or vice-versa. Two subroutines called
IJTOLL and LLTOIJ perform these functions. The source code and documentation for
both of these subroutines are contained in Appendix A. Note: If applying IJTOLL and
LLTOIJ to the Mapped GAC Product, use a prime longitude of +80W.




                                           5-54         NOAA POD Guide - Jan. 2002 Revision54
5.3.1.1        Mapped GAC (Polar Stereographic) Product - Oct. 26, 1994 to
               present

On Oct. 26, 1994, NESDIS replaced the Polar Stereographic GAC mapping system with
the NOAA-KLM master map system. This resulted in corresponding format changes.
This section describes the format of the Polar Stereographic Mapped GAC product in use
since Oct. 26, 1994.

The data are organized as daytime and nighttime for the northern and southern
hemispheres. The daytime data contain both visible (Channel 1) and IR (Channel 4) data
while the nighttime data contain only the IR data. The data are reported in pairs of files.
The first file of each file pair consists of a documentation record for that variable,
immediately followed by an EOF and a second file containing the data records for the
same variable. All records are 16,384 bytes in length. Both documentation and data
records are in binary format and have the same length. A value of zero indicates missing
data.

Every day a 3480 cartridge is created which contains one day of data in the Polar
Stereographic projection. Table 5.3.1.1-1 contains the general file structure of the daily
KLM Master map cartridge. Each cartridge contains 12 files arranged as shown in the
table.

     Table 5.3.1.1-1. General Structure of the Polar Stereographic KLM Master Map
                                        cartridge.
  File #    Record #                                     Contents
                       Daytime Northern Hemisphere - Visible Channels
     1           1      Channel 1 documentation record. See Table 5.3.1.1-2 for format.
     2        1-1024    Channel 1 data records. Consists of 16,384 bytes of data or 4 mapped
                        rows of data. Each row contains 4096 pixels of data. Each pixel is one
                        byte. A value of 0 indicates missing data.
                         Daytime Northern Hemisphere - IR Channels
     3           1      Channel 4 documentation record. See Table 5.3.1.1-2 for format.
     4        1-1024    Channel 4 data records. Same as File 2 data records.
                       Daytime Southern Hemisphere - Visible Channels
     5           1      Channel 1 documentation record. See Table 5.3.1.1-2 for format.
     6        1-1024    Channel 1 data records. Same as File 2 data records.
                         Daytime Southern Hemisphere - IR Channels
     7           1      Channel 4 documentation record. See Table 5.3.1.1-2 for format.



                                          5-55         NOAA POD Guide - Jan. 2002 Revision55
    8       1-1024     Channel 4 data records. Same as File 2 data records.
                      Nighttime Northern Hemisphere - IR Channels
    9          1       Channel 4 documentation record. See Table 5.3.1.1-2 for format.
    10      1-1024     Channel 4 data records. Same as File 2 data records.
                      Nighttime Southern Hemisphere - IR Channels
    11         1       Channel 4 documentation record. See Table 5.3.1.1-2 for format.
    12      1-1024     Channel 4 data records. Same as File 2 data records.

The variables reported in the documentation record are all INTEGER*2 with the
exception of the satellite type in the first two bytes of the record, which is
CHARACTER*2. Table 5.3.1.1-2 defines the basic documentation record format.

 Table 5.3.1.1-2. Format of Documentation Record for Polar Stereographic KLM Master
                                     Map Data.
   Byte #                                        Contents
    1-2      Satellite type, e.g., NH=NOAA-H (CHARACTER*2)
    3-4      Satellite ID:
              0=morning satellite
              1=afternoon satellite
    5-6      Data set type:
              1=LAC
              2=GAC
              3=HRPT
    7-8      Projection type:
              0=unmapped
              1=Mercator
              2=Polar
              3=linear latitude/longitude
                                      Image boundaries
    9-10     Beginning latitude x 128; North>0; South<0
   11-12     Ending latitude x 128
   13-14     Beginning longitude x 128; East>0; West<0
   15-16     Ending longitude x 128




                                       5-56         NOAA POD Guide - Jan. 2002 Revision56
17-18   Mapped resolution x 100; km for polar and Mercator projections; degree/pixel
        for linear latitude/longitude projections; sampling interval for unmapped
        projection
19-22   Spares
                              Polar Projection Data
23-24   Polar grid mesh size (grid size that corresponds to resolution, e.g., 64=1/64 grid)
25-26   Number of grid points (that correspond to grid size, e.g., 1/64 corresponds to
        4096 points)
27-28   Hemisphere:
         1=Northern
         -1=Southern
29-30   Prime longitude; East>0; West<0
                                    Grid Offsets
31-32   IOFF; grid coordinates of top left corner of the image (not applicable for
        unmapped projections)
33-34   JOFF
                                     Image Size
35-36   Number of rows
37-38   Number of columns
39-42   Spares
43-44   Composite flag:
         0=no composite
         1=composite based on minimum nadir angle
         2=retain average value
         3=retain later value
         4=retain warmer value
         5=retain colder value
45-46   Calibration flag:
         0=raw counts
         1=radiances
         2=calibrated to albedos and brightness temperatures
         3=calibrated to albedos and GOES counts
47-48   Fill-up options:
         0=no fill up
         1=fill up using averages
         2=fill up using adjacent pixel values


                                   5-57          NOAA POD Guide - Jan. 2002 Revision57
49-50   Channel number:
        1-5=channel number
        101=scan angle
        102=satellite zenith angle
        103=solar zenith angle
        104=relative azimuth angle
        105=scan time
        201=SST split window
        202=SST dual window
        203=SST Triple window
51-52   Data ID:
        0=visible
        1=infrared
        2=ancillary
                              Data Correction Flags
53-54   Sun normalization:
         0=not performed
         1=performed
55-56   Limb correction:
        0=not performed
        1=performed
57-58   Nonlinearity correction:
        0=not performed
        1=performed
59-60   Number of orbits processed
                                   Channel Images
61-62   Number of channels produced
63-64   Pixel size:
        1=1 byte
        2=2 bytes
65-66   Starting block number
67-68   Ending block number
                                   Ancillary Data
69-70   Number of ancillary parameters produced
71-72   Pixel size:
         1=1 byte
         2=2 bytes



                                   5-58       NOAA POD Guide - Jan. 2002 Revision58
 73-74    Starting block number
 75-76    Ending block number
 77-78    Block size of image files
 79-80    Compression flag
81-100    Spares
                                  Orbit 1 information
101-102   Orbital node over region:
           -1=ascending
           1=descending
           2=both
103-104   Day/night flag:
          0=day
          1=night
                               Image Data Boundaries
105-106   Start row
107-108   Start column
109-110   End row
111-112   End column
                                      Orbit Start Time
113-114   Year of century
115-116   Day of year
117-118   Month and day of month (month x 100) + day
119-120   Hours and minutes (hours x 100) + minutes
121-122   Seconds
123-124   Milliseconds
                                      Orbit End Time
125-126   Year of century
127-128   Day of year
129-130   Month and day of month (month x 100) + day
131-132   Hours and minutes (hours x 100) + minutes



                                       5-59       NOAA POD Guide - Jan. 2002 Revision59
  133-134     Seconds
  135-136     Milliseconds
  137-138     Processing Block ID (orbit number)
                                         Quality Flags
  139-140     Ramp/auto calibration flag
  141-142     Number of data gaps
  143-144     Sync errors
  145-146     TIP parity errors
  147-148     Auxiliary errors
  149-150     Calibration parameter ID
  151-152     DACS status
                                    Calibration Coefficients
  153-154     Channel 1 slope x 10,000
  155-156     Channel 1 intercept x 1,000
  157-158     Channel 2 slope x 10,000
  159-160     Channel 2 intercept x 1,000
  161-166     Spares
                                      Orbit 2 Information
  167-232     Same as bytes 102-166
                                      Orbit 3 Information
  233-298     Same as bytes 102-166
     ...      ...
                                     Orbit n Information
   ((n-1) x   Same as bytes 102-166
  66+102)-
   ((n-1) x
  66+166)

Each data record (16,384 bytes) consists of four mapped rows, each containing 4096
pixels of data. Each pixel is represented by one byte of data.




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5.3.2          Mapped GAC (Mercator)

Beginning June 24, 1985, SSB began archiving the Mapped GAC Product in the
Mercator form. These mapped mosaics are displayed on a Mercator map which extends
from 40N to 40S with a 9.8 km resolution at the Equator, and 7.5 km resolution at 40N
and 40S. The Mercator mapped GAC data reside in Files 9 through 11 of the same
archive tape as the Polar Stereographic mapped GAC. The Mercator files have the file
structure as shown in Table 5.3.2-1. The first record of each file contains documentation
for that file and it has the same format as the documentation for the Polar Stereographic
mapped GAC product described in Section 5.3.1.

               Table 5.3.2-1. File Structure of Mapped GAC Data (Mercator
   File #     Record #     Bytes/record                          Contents
        9         1             4052        Nighttime IR documentation
                2-985           4052        Nighttime IR data
        10        1             4052        Daytime IR documentation
                2-985           4052        Daytime IR data
        11        1             4052        Visible documentation
                2-985           4052        Visible data


The data are contained in records 2 through 985 of each Mercator file. Each record
contains data for one mapped row and 984 records comprise the Mercator map. The
4,052 byte records hold 4,050 8-bit bytes of data with the rightmost two bytes zero filled.
The temperature values for IR data range from 0 (warm) to 254 (cold) and the visible data
count values range from 0 (dark) to 254 (bright). Figure 5.3.2-1 shows the arrangement
of the Mercator mapped GAC data for one file.




                                          5-61        NOAA POD Guide - Jan. 2002 Revision61
               Figure 5.3.2-1. Arrangement of Data on Mercator Map.

5.3.2.1        Mapped GAC (Mercator) Product - Oct. 26, 1994 to present

On Oct. 26, 1994, NESDIS replaced the Polar Stereographic GAC mapping system with
the NOAA-KLM master map system. This resulted in corresponding format changes.
This section describes the format of the Mercator Mapped GAC product in use since Oct.
26, 1994.

The data reported are organized as visible (Channel 1), and daytime and nighttime IR
(Channel 4). These data are reported in pairs of files, totaling six files. The first file of
each file pair consists of a documentation record for that variable, immediately followed
by an EOF and a second file containing the data records for the same variable. All
records are 4,052 bytes in length. Both documentation and data records are in binary
format and have the same length. A value of zero indicates missing data.

Every day a 3480 cartridge is created which contains a day of data in the Mercator
projection. Table 5.3.2.1-1 contains the general file structure of the daily Mercator
Master map cartridge. Each cartridge contains 6 files arranged as shown in the table.

     Table 5.3.2.1-1. General Structure of the Mercator KLM Master Map Cartridge.
   File #      Record #                                    Contents




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                                       Visible Channels
      1           1       Channel 1 documentation record. See Table 5.3.1.1-2 for format
      2         1-984     Channel 1 data records. Consists of 4,052 bytes of data or 1 mapped
                          row of data. Each row contains 4052 pixels of data. Each pixel is
                          one byte. A value of 0 indicates missing data.
                                    IR Channels (Daytime)
      3           1       Channel 4 documentation record. See Table 5.3.1.1-2 for format.
      4         1-984     Channel 4 data records. Same as File 2 data records
                                   IR Channels (Nighttime)
      5           1       Channel 4 documentation record. See Table 5.3.1.1-2 for format.
      6         1-984     Channel 4 data records. Same as File 2 data records

The format of the basic documentation record is the same as the Polar Stereographic
KLM Master Map which is contained in Table 5.3.1.1-2.

Each data record (4,052 bytes) consists of one mapped row, containing 4052 pixels of
data. Each pixel is represented by one byte of data.

5.4           Radiation Budget Products

There are six types of digital Radiation Budget products that were archived by SSB for
the NOAA Polar Orbiting satellites through May 1999. For any data after May 1999,
including some NOAA-14 data, please see Section 9.3.1 of the NOAA KLM User’s
Guide for the archive format. All radiation budget products are currently produced by the
NOAA/NESDIS Office of Satellite Data Processing and Distribution's Product Systems
Branch (OSDPD/PSB).

The first type is the Monthly Radiation Budget. This data has eleven fields per day and
one calendar month per IBM 3480 cartridge. Archival of these tapes began in January
1979 and continues through the present. See Section 5.4.1 for a full description and
format of this product.

The second type of Radiation Budget product is known as the Seasonal Radiation Budget.
There are twenty fields per day and three calendar months per IBM 3480 cartridge,
stacked by season (i.e., Winter - December through February, Spring - March through
May, Summer - June through August, and Autumn - September through November).
These twenty fields include everything that is contained on the Monthly Radiation
Budget tapes plus more. Archival began with the June through August 1974 season and
continues through the present. See Section 5.4.2 for a description and format of this
product.



                                         5-63        NOAA POD Guide - Jan. 2002 Revision63
The third type of Radiation Budget product is the 10-year Mercator Radiation Budget
product which is a subset of the Seasonal Radiation Budget. There are four fields per day
mapped into a Mercator array and three IBM 3480 cartridges contain 10 years of non-
contiguous data. The 10-year period includes from June 1974 through March 1978
(which uses the VHRR instrument from NOAA-3, 4, and 5), and January 1979 through
February 1986 (using the AVHRR instrument on the TIROS-N series).

The fourth type of Radiation Budget product is the Monthly Mean Radiation Budget.
There are forty-five months (June 1974 through February 1978) of mean radiation budget
data (which were generated from the VHRR instrument on-board NOAA-3, -4, and -5)
which are contained on two IBM 3480 cartridges. One CCT contains data on Mercator
grids and the other CCT contains the same data on Polar Stereographic grids. The
algorithm used to compute radiation budget parameters was changed after the generation
of these tapes and these are the only RA/ASB Radiation Budget products which have not
been corrected. The monthly mean data for the TIROS-N series are available from
January 1979 through the present. See Section 5.4.3 for a description and format of this
product

The fifth and sixth types of radiation budget products are the seasonal mean and the
annual mean. The seasonal mean consists of averages over each season while the annual
mean consists of averages calculated over each calendar year. Both types of data have
the same format as the monthly mean radiation budget product described in Section 5.4.3.

5.4.1          Monthly Radiation Budget

The format of the monthly radiation budget data has evolved over the years since it was
first offered in January 1979 with the onset of TIROS-N polar orbiter data. The data
between January 1979 and the end of September 1988 were created with a certain format
and blocking scheme (herein referred to as the "Old" format). These data are described in
Section 5.4.1.1. Beginning in July 1987, a new format accompanied by a new blocking
scheme was introduced (herein referred to as the "New" format). These data are
described in Section 5.4.1.2. However, there was a certain time period in which both
formats were mixed on the archive tapes (July 1987 - September 1988) depending on
whether the satellite was designated primary or secondary. The following documentation
attempts to record the logical progression of the monthly radiation budget data formats.

5.4.1.1        Old Monthly Radiation Budget format

The monthly radiation budget archive tape contains daily sets of radiation budget data
fields for a calendar month. A daily set consists of both Polar Stereographic and 2.5 x 2.5
degree gridded Mercator arrays of Nighttime Longwave Radiation, Daytime Longwave
radiation, and Absorbed Solar Radiation. Polar Stereographic arrays of Available Solar
Energy are also included.

Each daily set of data fields contains the following arrays stacked in the file in this order:
       1) Nighttime Longwave Radiation Northern Hemisphere Polar stereo (125 x 125)



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       2) Nighttime Longwave Radiation Southern Hemisphere Polar stereo (125 x 125)
       3) Nighttime Longwave Radiation 2.5 x 2.5 degree (144 x 72)
       4) Daytime Longwave radiation Northern Hemisphere Polar stereo (125 x 125)
       5) Daytime Longwave radiation Southern Hemisphere Polar stereo (125 x 125)
       6) Daytime Longwave radiation 2.5 x 2.5 degree (144 x 72)
       7) Available Solar Energy Northern Hemisphere Polar stereo (125 x 125)
       8) Available Solar Energy Southern Hemisphere Polar stereo (125 x 125)
       9) Absorbed Solar Radiation Northern Hemisphere Polar stereo (125 x 125)
       10) Absorbed Solar Radiation Southern Hemisphere Polar stereo (125 x 125)
       11) Absorbed Solar Radiation 2.5 x 2.5 degree (144 x 72)

These daily sets of data fields are stacked chronologically on the tape, day by day (up to
31 days worth of data). All data values are contained in 2-byte integer words and are in
units of W/m2 x 10. Missing data values are indicated by a value of -9999. The data
values of Available Solar Energy are flagged with a minus sign at those grid points where
the corresponding values of Absorbed Solar Energy are missing.

Each monthly radiation budget tape contains two files. The first file contains the data for
the primary operational satellite and the second file contains data for the secondary
operational satellite. The block size is 4000 bytes with record format VS (variable length
records spanning block boundaries) and all records are 4000 bytes in length except for the
records containing the remaining data in each array. Since the tape is written with the
IBM VS option, the first 8 bytes of each 4000-byte physical record contain VS
information and should be skipped by the non-IBM user. Table 5.4.1.1-1 shows the
expected record lengths (which includes the 8-bytes of VS information) for the first three
data arrays.

   Table 5.4.1.1-1. Record Length for First Three Data Arrays in the Old Monthly Heat
                                      Budget Data.
  Record #     # of Bytes                            Type of data array
      1           4000
      2           4000
      3           4000
      4           4000       Nighttime Longwave Radiation Polar Stereo Northern Hemisphere
                                                     (125 x 125)
      5           4000
      6           4000
      7           4000
      8           3314
      9           4000       Nighttime Longwave Radiation Polar Stereo Southern Hemisphere



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     10            4000                                 (125 x 125)

     11            4000
     12            4000
     13            4000
     14            4000
     15            4000
     16            3314
     17            4000
     18            4000
     19            4000
                                    Nighttime Longwave Radiation Mercator (144 x 72)
     20            4000
     21            4000
     22            784

In the Polar Stereographic form, each hemisphere of data is contained in a 125 x 125
array written row by row. These data are contained in 31,250-byte logical records. The
data values fit the intersections of a square mesh overlaid on a Polar Stereographic
projection. Array (63,63) lies on the Pole. The arrays for both hemispheres are oriented
such that Array (63,1) represents the data at 0.4N, 100E in the Northern Hemisphere
array and 0.4S, 80W in the Southern Hemisphere array.

Documentation for the Polar Stereographic arrays is contained in Table 5.4.1.1-2.

             Table 5.4.1.1-2. Documentation for the Polar Stereographic Arrays.
          Location                                       Contents
          Array (1,1)        Month
          Array (2,1)        Day
          Array (3,1)        Year
          Array (4,1)        Data type:
                             1=day flux
                             2=night flux
                             4=Available Solar Energy
                             5=Absorbed Solar Radiation




                                         5-66        NOAA POD Guide - Jan. 2002 Revision66
        Array (5,1)           Hemisphere:
                              1=Northern
                              2=Southern

The 2.5 x 2.5 degree gridded Mercator arrays contain data values that fit the intersection
of a 2.5 degree latitude/longitude mesh that covers the globe. These arrays are contained
in 20,736-byte logical records. The top row of 144 words contains documentation and
the data values for the Poles. In the Absorbed Solar Radiation array, Array (27,1)
through Array (99,1) contain values of Available Solar Energy for each 2.5 degree
interval of latitude from 90N to 90S. The remaining 71 rows of 144 words each contain
data for the latitude circles at 2.5 degree intervals from 87.5N to 87.5S. The 144 data
values in each row fit a latitude circle in which the first word contains the data value for
0E, the second word 2.5E, etc. Missing data have been filled in by interpolation and
these values are flagged with a minus sign.

Documentation for the 2.5 x 2.5 degree Mercator arrays is contained in Table 5.4.1.1-3.

          Table 5.4.1.1-3. Documentation for the 2.5 x 2.5 Degree Mercator Arrays
        Location                                           Contents
       Array (3,1)          Year
       Array (4,1)          Month
       Array (5,1)          Day
       Array (6,1)          Data type:
                            1=day flux
                            2=night flux
                            4=Available Solar Energy
                            5=Absorbed Solar Radiation
       Array (25,1)         North Pole data value
       Array (26,1)         South Pole data value

5.4.1.2        New Monthly Radiation Budget Format
The monthly radiation budget (also known as the Radiation Budget monthly) data
contains daily sets of Radiation Budget data fields for a calendar month. The data fields
are copied from the Radiation Budget 37-day file in chronological order.

Each daily set of data contains Polar Stereographic hemispheric arrays and 2.5 x 2.5
degree global Mercator arrays. The arrays contain data parameters which describe the
three Radiation Budget quantities: Daytime Longwave Radiation, Nighttime Longwave
Radiation, and Absorbed Solar Radiation. There are also Polar Stereographic
hemispheric arrays of Available Solar Energy.



                                          5-67         NOAA POD Guide - Jan. 2002 Revision67
In addition to the arrays containing average values of the Radiation Budget quantities,
there are arrays of Class Interval Populations and arrays of the variances of the values
making up the averages.

A daily set of fields is made up of three subsets of arrays. Each subset contains data
parameters which describe one of the Radiation Budget quantities. A daily set contains
the following subsets:

       1.      Nighttime Longwave Radiation
       2.      Daytime Longwave Radiation
       3.      Absorbed Solar Radiation

Each subset contains the following arrays:

       1.      Northern Hemisphere polar stereo array of data values (125 x 125)
       2.      Southern Hemisphere polar stereo array of data values (125 x 125)
       3.      2.5 x 2.5 degree Mercator array of data values (144 x 72)
       4.      Northern Hemisphere polar stereo array of 1st Class Interval Pop. (125 x
               125)
       5.      Southern Hemisphere polar stereo array of 1st Class Interval Pop. (125 x
               125)
       6.      Northern Hemisphere polar stereo array of 2nd Class Interval Pop. (125 x
               125)
       7.      Southern Hemisphere polar stereo array of 2nd Class Interval Pop. (125 x
               125)
       8.      Northern Hemisphere polar stereo array of 3rd Class Interval Pop. (125 x
               125)
       9.      Southern Hemisphere polar stereo array of 3rd Class Interval Pop. (125 x
               125)
       10.     Northern Hemisphere polar stereo array of variances (125 x 125)
       11.     Southern Hemisphere polar stereo array of variances (125 x 125)
       12.     2.5 x 2.5 degree Mercator array of variances (144 x 72)

The subset containing Absorbed Solar Radiation data differs from the others in that there
are the following arrays at the beginning of the subset:

       1.      Northern Hemisphere polar stereo array of Available Solar Energy (125 x
               125)
       2.      Southern Hemisphere polar stereo array of Available Solar Energy (125 x
               125)

In the Polar Stereographic form, each hemisphere of data is contained in a 125 x 125
array written row by row. The data values fit the intersections of a square mesh overlaid
on a Polar Stereographic projection. Array (63,63) lies on the Pole. The arrays for both
hemispheres are oriented such that Array (63,1) represents the data at 0.4N, 100E in the
Northern hemisphere array and 0.4S, 80W in the Southern hemisphere array.



                                          5-68         NOAA POD Guide - Jan. 2002 Revision68
Documentation for the Polar Stereographic arrays is contained in Table 5.4.1.2-1.

       Table 5.4.1.2-1. Documentation for the Monthly Polar Stereographic Arrays.
            Location                                         Description
           Array (1,1)               Month
           Array (2,1)               Day
           Array (3,1)               Year
           Array (4,1)               Data Type:
                                     1st digit (or only digit)
                                        1 = Daytime Longwave Radiation
                                        2 = Nighttime Longwave Radiation
                                        4 = Available Solar Energy
                                        5 = Absorbed Solar Radiation
                                     2nd digit
                                        6 = Class Interval Population
                                        7 = Variance
                                     3rd digit
                                        1 = 1st Class Interval
                                        2 = 2nd Class Interval
                                        3 = 3rd Class Interval

The 2.5 x 2.5 degree arrays contain data values that fit the intersections of a 2.5 degree
latitude/longitude mesh that covers the globe. The top row of 144 contains
documentation and the values for the Poles. The remaining 71 rows, of 144 words each,
contain data for the latitude circles at 2.5 degree intervals from 87.5N to 87.5S. The 144
data values in each row fit a latitude circle where the first word contains the value for 0E
longitude, the second word contains the value for 2.5E longitude, etc. In all the 2.5 x 2.5
degree arrays, missing data has been filled in by interpolation and all interpolated values
are flagged with a minus sign.

The format for the documentation of the 2.5 by 2.5 degree arrays is contained in Table
5.4.1.2-2.

     Table 5.4.1.2-2. Documentation in the Monthly 2.5 x 2.5 Degree Mercator Arrays.
          Location                                         Description
         Array (3,1)           Year
         Array (4,1)           Month
         Array (5,1)           Day



                                            5-69       NOAA POD Guide - Jan. 2002 Revision69
        Array (6,1)           Data type:
                               1 = Daytime Longwave Radiation
                               2 = Nighttime Longwave Radiation
                               3 = Absorbed Solar Radiation
        Array (25,1)          North Pole value
        Array (26,1)          South Pole value

The 2.5 x 2.5 degree array of Absorbed Solar Radiation contains values of Available
Solar Energy in the top row. Beginning in Array (27,1) through Array (99,1) are the
values of Available Solar Energy for each 2.5 degrees of latitude from 90N to 90S.

All data values and variances are in units of W/m2. All data values have been multiplied
by 10. In all fields, missing data are indicated by -9999. All fields reside in INTEGER*2
(FORTRAN 77) arrays.

The data values in the Polar Stereographic arrays of Available Solar Energy are flagged
with a minus sign at those grid points where the corresponding values of Absorbed Solar
Radiation are missing.

In the Class Interval Population arrays of Outgoing Longwave radiation, the populations
represent the following:

       1st Class Interval = Values greater than 174
       2nd Class Interval = Values from 136 through 174
       3rd Class Interval = Values less than 136

In the Class Interval Population arrays of Absorbed Solar Radiation, the populations
represent the following:

       1st Class Interval = Values greater than 150
       2nd Class Interval = Values from 100 through 150
       3rd Class Interval = Values less than 100

The Class Interval Populations are biased with a value of -9000. Missing data is
indicated with a value of -9999. A value of 9000 must be added to all values greater than
-9999 in order to obtain the true population.

Each 125 x 125 Polar Stereographic array is written to tape in six segments. The first
five segments contain 21 rows (5,250 bytes), and the sixth segment contains 20 rows
(5,000 bytes).

Each 144 x 72 Mercator array is written to tape in four segments of 18 rows each (5,184
bytes).

Table 5.4.1.2-3 shows how the data in the New format are blocked on the tape.


                                         5-70         NOAA POD Guide - Jan. 2002 Revision70
       Table 5.4.1.2-3. Blocking of Data for the Monthly Radiation Budget
Record #                                 # of Bytes
  Nighttime Longwave radiation Polar Stereo Northern Hemisphere (125 x 125)
   1                                        4000
   2                                        1266
   3                                        4000
   4                                        1266
   5                                        4000
   6                                        1266
   7                                        4000
   8                                        1266
   9                                        4000
  10                                        1266
  11                                        4000
  12                                        1016
  Nighttime Longwave Radiation Polar Stereo Southern Hemisphere (125 x 125)
  13                                        4000
  14                                        1266
  15                                        4000
  16                                        1266
  17                                        4000
  18                                        1266
  19                                        4000
  20                                        1266
  21                                        4000
  22                                        1266
  23                                        4000
  24                                        1016


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                    Nighttime Longwave Radiation Mercator (144 x 72)
        25                                           4000
        26                                           1200
        27                                           4000
        28                                           1200
        29                                           4000
        30                                           1200
        31                                           4000
        32                                           1200

Radiation budget data collected between July 1987 and July 1988, had two files which
were not only blocked differently, but were also formatted differently. File 1 contained
radiation budget data for the primary satellite (NOAA-9) in the old format and was
blocked as shown in Table 5.4.1.1-1, while File 2 which contained radiation budget data
for the secondary satellite (NOAA-10) in the new format was blocked as shown in Table
5.4.1.2-3. This confusing situation finally ended when NOAA-9 was replaced by
NOAA-11 as the primary satellite in October 1988. At that time, the new format was
used for both operational satellites.

From October 1988 through May 1999, monthly radiation budget data have had both files
blocked as shown in Table 5.4.1.2-3.

5.4.2           Seasonal Radiation Budget Product

The Seasonal Radiation Budget archive tape contains 90 - 92 daily data sets. A daily data
set consists of four radiation fields written in the following order: 1) Daytime Outgoing
Longwave, 2) Absorbed Solar Energy, 3) Available Solar Energy, and 4) Nighttime
Outgoing Longwave. Each radiation field consists of five arrays in the following order:
1) Northern Hemisphere Polar Stereographic, 2) Southern Hemisphere Polar
Stereographic, 3) Northern Hemisphere Polar Chip, 4) Southern Hemisphere Polar Chip,
and 5) a latitude/longitude Mercator grid. These data are available from June 1974
through May 1999.

Each daily data set contains the following arrays in the indicated order:

   1.   Day Flux Northern Hemisphere 125 x 125 array
   2.   Day Flux Southern Hemisphere 125 x 125 array
   3.   Day Flux Northern Hemisphere Chip 45 x 45 array
   4.   Day Flux Southern Hemisphere Chip 45 x 45 array
   5.   Day Flux Mercator 144 x 72 array
   6.   Absorbed Solar Energy Northern Hemisphere 125 x 125 array


                                          5-72         NOAA POD Guide - Jan. 2002 Revision72
   7. Absorbed Solar Energy Southern Hemisphere 125 x 125 array
   8. Absorbed Solar Energy Northern Hemisphere Chip 45 x 45 array
   9. Absorbed Solar Energy Southern Hemisphere Chip 45 x 45 array
  10. Absorbed Solar Energy Mercator 144 x 72 array
  11. Available Solar Energy Northern Hemisphere 125 x 125 array
  12. Available Solar Energy Southern Hemisphere 125 x 125 array
  13. Available Solar Energy Northern Hemisphere Chip 45 x 45 array
  14. Available Solar Energy Southern Hemisphere Chip 45 x 45 array
  15. Available Solar Energy Mercator 144 x 72 array
  16. Nighttime Flux Northern Hemisphere 125 x 125 array
  17. Nighttime Flux Southern Hemisphere 125 x 125 array
  18. Nighttime Flux Northern Hemisphere Chip 45 x 45 array
  19. Nighttime Flux Southern Hemisphere Chip 45 x 45 array
  20. Nighttime Flux Mercator 144 x 72 array

In the Polar Stereographic form, each hemisphere of data is contained in a 125 x 125
array written row by row. The data values fit the intersections of a square mesh overlaid
on a Polar Stereographic projection. Array (63,63) lies on the Pole. The arrays for both
hemispheres are oriented such that array (63,1) is at latitude 0.4N and longitude 100E in
the Northern Hemisphere array and at latitude 0.4S and longitude 80W in the Southern
Hemisphere array.

The documentation in the Polar Stereographic arrays is contained in Table 5.4.2-1.

         Table 5.4.2-1. Documentation in the Seasonal Polar Stereographic arrays.
         Location                                       Description
        Array (1,1)          Month
        Array (2,1)          Day
        Array (3,1)          Year
        Array (4,1)          Data type:
                             1 = Day Flux
                             2 = Night Flux
                             4 = Available Solar Energy
                             5 = Absorbed Solar Energy
        Array (5,1)          Hemisphere:
                             1 = Northern
                             2 = Southern

The Polar Stereographic chips are the center portion of the complete 125 x 125 Polar
Stereographic arrays. The 45 x 45 chip arrays are written row by row and oriented in the
same manner as the larger Polar Stereographic arrays. The chips contain no



                                         5-73         NOAA POD Guide - Jan. 2002 Revision73
documentation. Missing data have been filled in by interpolation and all interpolated
values are flagged with a minus sign.

The Mercator arrays contain data values that fit the intersections of a 2.5 degree
latitude/longitude mesh that covers the globe. The top row of 144 words (1 word = 2
bytes) contains documentation. The remaining 71 rows of 144 words each contain data
for the latitude circles at 2.5 degree intervals from 87.5N to 87.5S. The 144 word data
values in each row fit a latitude circle where the first word contains the data value for 0E,
the second word 2.5E, etc. Missing data are handled in the same manner as described in
the Polar Stereographic chips.

The documentation in the 144 x 72 Mercator arrays is contained in Table 5.4.2-2.

           Table 5.4.2-2. Documentation in the Seasonal 144 x 72 Mercator Arrays.
               Location                                       Description
              Array (3,1)             Year
              Array (4,1)             Month
              Array (5,1)             Day
              Array (6,1)             Data type
          Array (7,1) - (10,1)        Satellite name in BCD
             Array (25,1)             North Pole data value
             Array (26,1)             South Pole data value

All data are stored in 2 byte (16 bit) words and recorded in binary. All data values are in
units of W/m2 and have been multiplied by 10 before they are stored. The data values of
Available Solar Energy are flagged with a minus sign at those grid points where the
corresponding values of Absorbed Solar Energy are missing or have been interpolated.
Missing data is indicated by a value of -999910. Note: the record format VS option was
used to create the CCT (See Section 5.4.1 for further explanation).

5.4.2.1          10-Year Mercator Radiation Budget Product

The 10-Year Mercator Radiation Budget product consists of daily data sets in Mercator
form spanning approximately ten-years (non-contiguous). This product is a subset of the
Seasonal Radiation Budget product. The daily data contain the following arrays in the
indicated order:

   1. Day flux Mercator 144 x 72 array
   2. Absorbed Solar Energy Mercator 144 x 72 array
   3. Available Solar Energy Mercator 144 x 72 array
   4. Nighttime Flux Mercator 144 x 72 array


                                            5-74        NOAA POD Guide - Jan. 2002 Revision74
The Mercator arrays and data values are structured exactly the same as the Mercator
arrays described in Section 5.4.2. However, the documentation in the 144 x 72 Mercator
arrays differs slightly and has the format shown in Table 5.4.2.1-1.

          Table 5.4.2.1-1. Format of documentation for the 144 x 72 Mercator Arrays.
          Location                                       Content
        Array (3,1)      Year
        Array (4,1)      Month
        Array (5,1)      Day
        Array (6,1)      Data Type:
                          1=Day Flux
                          2=Night Flux
                          4=Available Solar Energy
                          5=Absorbed Solar Energy
        Array (25,1)     North Pole data value
        Array (26,1)     South Pole data value

Three IBM 3480 cartridges contain the data as follows:

   1. June 1, 1974 - March 16, 1978 (Pre TIROS-N satellites, NOAA-3, 4, 5)
   2. January 1, 1979 - November 30, 1982 (TIROS-N series)
   3. December 1, 1982 - February 28, 1986 (TIROS-N series)
These non-labeled archive tapes were created using the record format VS option and a
block size of 4000.

5.4.3            Monthly Mean Radiation Budget Products

Two formats exist for the Monthly Mean Radiation Budget Products. Basically, the only
difference is that the older format separated the two projections (Mercator and Polar
Stereographic) onto two different archive tapes, while the current format combines both
projections on the same archive tape. The current format began on Oct. 1, 1987 and
continued through May 1999. This format is described in Section 5.4.3.1. The one used
for the period ending on Sept. 30, 1987, is described in Section 5.4.3.2.

5.4.3.1          Monthly Mean Radiation Budget Products (Oct. 1, 1987 to present)

The Monthly Mean Radiation Budget archives contain Monthly Mean data in 2.5 x 2.5
degree latitude/longitude grid called a Mercator Array and a 45 x 45 grid on a Polar
Stereographic map base. The mean data are derived from the daily archived arrays for
each calendar month. The Monthly Mean data set begins with November 1988. A



                                         5-75        NOAA POD Guide - Jan. 2002 Revision75
Monthly Mean data set consists of four groups of three (12 total) Radiation Fields. The
groups are written in the following order: Daytime Outgoing Longwave Radiation,
Nighttime Outgoing Longwave Radiation, Absorbed Solar Energy and Available Solar
Energy. Each group of three fields consist of a Northern Hemisphere polar stereo (45 x
45) chip, a Southern Hemisphere chip, and a 144 x 72 Mercator field.

Thus, the twelve Radiation Fields are stored in the following order:

1.    Daytime Flux Northern Hemisphere 45 x 45 Array
2.    Daytime Flux Southern Hemisphere 45 x 45 Array
3.    Daytime Flux Mercator 144 x 72 Array
4.    Nighttime Flux Northern Hemisphere 45 x 45 Array
5.    Nighttime Flux Southern Hemisphere 45 x 45 Array
6.    Nighttime Flux Mercator 144 x 72 Array
7.    Absorbed Solar Energy Northern Hemisphere 45 x 45 Array
8.    Absorbed Solar Energy Southern Hemisphere 45 x 45 Array
9.    Absorbed Solar Energy Mercator 144 x 72
10.   Available Solar Energy Northern Hemisphere 45 x 45 Array
11.   Available Solar Energy Southern Hemisphere 45 x 45 Array
12.   Available Solar Energy Mercator 144 x 72 Array

The 45 x 45 Polar Stereographic Array covers the area of 50N to 90N and 50S to 90S.
The 45 x 45 Arrays are written row by row. The data values fit the intersections of a
square mesh overlaid on a Polar Stereographic projection. Array (23,23) lies on the Pole.
The arrays for both hemispheres are oriented such that Array (23,1) is at latitude 50.4N
and longitude 80W in the Northern Hemisphere Array and at latitude 50.4S and longitude
80W in the Southern Hemisphere Array. The chips contain no documentation. Missing
data have been filled in by interpolation and all interpolated values are flagged with a
minus sign.

The Mercator Arrays contain data values that fit the intersections of a 2.5 degree
latitude/longitude mesh that covers the globe. The top row of 144 words (1 word = 2
bytes) contains documentation. The remaining 71 rows of 144 words each contain data
for the latitude circles at 2.5 degree intervals from 87.5N to 87.5S. The 144 word data
values in each row fit a latitude circle where the first word contains the data value for 0E,
the second word 2.5E, etc. Missing data are handled in the same manner as described for
the Polar Stereographic Arrays.

The documentation in the 144 x 72 Mercator Arrays is contained in Table 5.4.3.1-1.

         Table 5.4.3.1-1. Format of Documentation for the 144 x 72 Mercator Arrays.
 Location                                                 Content
 Array (3,1)             Year
 Array (4,1)             Month


                                          5-76          NOAA POD Guide - Jan. 2002 Revision76
 Array (5,1)            Day
 Array (6,1)            Data Type:
                         1=Day Flux
                         2=Night Flux
                         4=Available Solar Energy
                         5=Absorbed Solar Energy
 Array (7,1)            Number of days averaged
 Array (25,1)           North Pole data value
 Array (26,1)           South Pole data value

All data are stored in IBM 4 byte (REAL*4) words and recorded in binary on IBM 3480
cartridges. All data values are in units of W/m2. The data values of Available Solar
Energy are flagged with a minus sign at those grid points where the corresponding values
of Absorbed Solar Energy are missing or have been interpolated.

5.4.3.2         Monthly Mean Radiation Budget Products (before Oct. 1,1987

The Monthly Mean Radiation Budget archive tapes consist of two CCTs, one CCT
contains the monthly mean data in 2.5 x 2.5 degree Mercator form and the other contains
the data in Polar Stereographic form. Section 5.4.3.1 describes the format of the
Mercator form and Section 5.4.3.2 contains the format of the Polar Stereographic form.
5.4.3.2.1              Monthly Mean Radiation Budget (2.5 x 2.5 degree Mercator
                Arrays before Oct. 1, 1987)

The Monthly Mean Radiation Budget product in Mercator form contains 45 sets of
monthly mean Radiation Budget data. The mean data are derived from the daily archived
arrays for the calendar months. Each set consists of four arrays in the following order: 1)
Day IR Flux, 2) Night IR Flux, 3) Absorbed Solar Energy, and 4) Available Solar
Energy. Each array contains 144 X 72 words. The data are stored in one file consisting
of 180 records (4 arrays x 45 sets). The documentation and data values for the Poles for
each array are contained in the first row of 144 words as shown in Table 5.4.3.2.1-1.

      Table 5.4.3.2.1-1. Documentation and Data Values for the Poles for Each Array.
          Location                                          Contents
 Array (1,1)                    Null
 Array (2,1)                    Null
 Array (3,1)                    Year of beginning date
 Array (4,1)                    Month of beginning date
 Array (5,1)                    Day of beginning date


                                         5-77         NOAA POD Guide - Jan. 2002 Revision77
 Array (6,1)                    Data type:
                                 1=Day IR Flux
                                 2=Night IR Flux;
                                 4=Available Solar Energy
                                 5=Absorbed Solar Energy
 Array (7,1)                    Number of days used to compute mean
 Array (8,1)                    Month of ending date
 Array (9,1)                    Day of ending date
 Array (10,1)                   Year of ending date
 Array (25,1)                   North Pole data value
 Array (26,1)                   South Pole data value

The first set of data contains June 1974 and the 45th set contains February 1978 data with
all data sets in between ordered chronologically. The data value for each location has
been derived by a four-point smoothing routine from the 125 x 125 hemispheric arrays
(See Section 5.4.1) to represent the center of a 2.5 x 2.5 degree grid square. All data are
recorded as 32-bit floating point words and are in units of W/m2. Again, the record
format VS option was used to create this CCT (See Section 5.4.1 for further explanation).

5.4.3.2.2              Monthly Mean Radiation Budget (Polar Stereographic Arrays
                before Oct. 1, 1987)

The Monthly Mean Radiation Budget product in Polar Stereographic form contains 45 set
of monthly mean Radiation Budget data. A set consists of two hemispheric arrays for
each of four data types. Each hemispheric array contains 125 words per row for 125
rows. The sequence of arrays per set is:

   1.   Day Flux, Northern Hemisphere
   2.   Day Flux, Southern Hemisphere
   3.   Night Flux, Northern Hemisphere
   4.   Night Flux, Southern Hemisphere
   5.   Absorbed Solar Energy, Northern Hemisphere
   6.   Absorbed Solar Energy, Southern Hemisphere
   7.   Available Solar Energy, Northern Hemisphere
   8.   Available Solar Energy, Southern Hemisphere

The documentation is contained in the first five words (16 bits) of the first row in each
125 x 125 array. Table 5.4.3.2.2-1 describes the documentation.

The documentation is contained in the first five words (16 bits) of the first row in each
125 x 125 array. Table 5.4.3.2.2-1 describes the documentation.



                                          5-78          NOAA POD Guide - Jan. 2002 Revision78
            Table 5.4.3.2.2-1. Documentation in Polar Stereographic Projection.
               Location                                          Contents
 Array (1,1)                             Month
 Array (2,1)                             Number of days in the mean
 Array (3,1)                             Year, expressed in units and tens only
 Array (4,1)                             Data Type:
                                          1=Day Flux
                                          2=Night Flux
                                          4=Available Solar Energy (ASE)
                                          5=Absorbed Solar Energy
 Array (5,1)                             Hemisphere:
                                          1= Northern
                                          2=Southern

Each 125 x 125 array represents a square mesh overlaid on a Polar Stereographic
projection of the relevant hemisphere. Array (63,63) lies on the pole of that hemisphere.
Array (1,63) is located 0.4 degrees poleward of the equator and 170W, while Array
(125,1) is 0.4 degrees poleward at longitude 10E. Array (63,1) is located at 0.4N, l00E
for the Northern hemisphere array and at 0.4S, 80W for the Southern hemisphere array.

All data are 16-bit integer words and are in units of W/m2. The data and documentation
words are multiplied by 10 before storing. All the data are contained in one file. Note:
The record format VS option was used to create this CCT (see Section 5.4.1 for further
explanation).

5.5            SBUV/2 Ozone Products

There are three types of SBUV/2 ozone products. They are the 1b Capture product, the
Historical Instruments file product and the Product Master File product. The format
description for all three of these products are listed in the Solar Backscattered Ultraviolet
Radiometer Version 2 (SBUV/2) User's Guide, which is available from SSB.

The 1b Capture product contains all SBUV/2 sensor data and support data necessary for
the derivation of atmospheric ozone and solar flux.

The Historical Instrument File contains the data necessary to characterize the instrument
performance and albedo correction over time.

The Product Master File contains the ozone information derived by the ozone algorithm,
located in space and time, other meteorological information developed in support of the
ozone



                                          5-79          NOAA POD Guide - Jan. 2002 Revision79
computations, parameters indicating the validity of the individual ozone retrievals and the
radiance information derived from the SBUV/2 measurements.

There are two main classes of SBUV/2 ozone products: operational and reprocessed.
The Operational products are generated by the NOAA/NESDIS Office of Satellite Data
Processing and Distribution's Product Systems Branch. The Reprocessed products are
generated by the NOAA/NESDIS Office of Research and Application's Physics Branch.
Operational data are kept in the archive until replaced by Reprocessed data. There are 14
to 15 orbits per day and one calendar month per cartridge tape.

The operational NOAA-9 data set begins with March 1985 and ends February 20, 1998.
The operational NOAA-11 data set begins with January 1989 and ends April 1995. It was
restarted on June 8, 1999 and continues to the present. The operational NOAA-14 data set
begins with February 1995 and continues to the present.

The NOAA-9 SBUV/2 total ozone data have been reprocessed for the time period 1985-
1997 with improved instrument characterization and calibration. The improved
calibration includes time dependent changes to solar diffuser reflectivity, photomultiplier
tube gain range ratios, and photomultiplier tube hysteresis correction. The newly
reprocessed NOAA-9 total ozone data have been validated at 2% by comparing with
ozone measurements made by ground-based Dobson stations. The NOAA-9 profile ozone
data will soon be reprocessed with improved calibration at shorter wavelengths.

The NOAA-11 SBUV/2 ozone data have been reprocessed for the time period 1989-1994
with improved instrument characterization and calibration. The improved calibration
includes time dependent changes to solar diffuser reflectivity and photomultiplier tube
gain range ratios. The reprocessed NOAA-11 total ozone data have been validated at 1%
by comparing with ozone measurements made by ground-based Dobson stations.
Reprocessing of NOAA-11 profile ozone data to correct for instrument and algorithm
errors are currently underway.

The NOAA-14 SBUV/2 ozone data have been reprocessed for the time period 1995-1998
with improved instrument characterization and calibration. The improved calibration
includes time dependent changes to solar diffuser reflectivity and photomultiplier tube
gain range ratios. The reprocessed NOAA-14 total ozone data have been validated at 2%
by comparing with ozone measurements made by ground-based Dobson stations.




                                         5-80         NOAA POD Guide - Jan. 2002 Revision80
Appendix A:            Polar Stereographic Earth Location
Two subroutines are provided for Earth location/navigation for NESDIS Operational
Products that are mapped onto a Polar Stereographic map base. These subroutines
provide the capability of converting the line, sample location of a data point on the Polar
Stereographic base to latitude and longitude (IJTOLL) or the reverse (LLTOIJ). With
proper specification of the input parameters, these subroutines may be used in
conjunction with the following:

       1.   Heat Budget Products (except Mercator)
       2.   Mapped GAC Products (except Mercator)
       3.   Pre TIROS-N Polar Stereographic SR Mosaics
       4.   Relative Cloud Cover Summary
       5.   Vegetation Index Data

Introduction

Subroutines IJTOLL and LLTOIJ are very similar in structure to each other. They are
described together where possible to avoid repetition. IJTOLL converts the i and j
coordinates of a point to latitude and longitude, whereas LLTOIJ converts the latitude and
longitude of a point to the i and j coordinates. Both require the origin of the map to be in
the upper left corner. Several parameters must be input in order to tailor IJTOLL and
LLTOIJ to a specific user's needs. Both subroutines have identical variables in their
argument lists. These variables are defined in Table A-1.

                Table A-1. Subroutines IJTOLL and LLTOIJ argument list.
 PRMLON           The prime longitude of the Polar Stereographic map base. This is defined as
                  the meridian which is perpendicular to the base of the map and which goes
                  from the pole to the bottom of the map. The map may be oriented as
                  desired. The prime longitude can be expressed as either positive 0 to 360W
                  or positive 0 to 180W and negative 0 to 180E.
 SCALE            The number of desired grid points between the pole and the equator.
 CENTI            The i coordinate representing the center of the array.
 CENTJ            The j coordinate representing the center of the array
 RI               The i coordinate of the point to be converted.
 RJ               The j coordinate of the point to be converted.
 PNTLAT           The latitude of the point written as positive 0 to 90N or negative 0 to 90S.
 PNTLON           The longitude of the point written as either positive 0 to 360W or positive 0
                  to 180W and negative 0 to 180E.




                                            A-1         NOAA POD Guide - Jan. 2002 Revision1
                                      POLDIS




                                  φ
                                         α
                                             Equator

                                                          SCALE
                              θ




 Note: IJTOLL has RI and RJ for inputs with the corresponding PNTLAT and PNTLON as
 outputs, and LLTOIJ uses PNTLAT and PNTLON as inputs to calculate the resultant RI and
 RJ as outputs.

             Figure A-1. Earth’s Cross-section to Derive Latitude
Program Operation

Subroutine IJTOLL computes the angle between the horizontal and a line drawn from the
pole to the point. From this angle and the prime longitude, the longitude of the point is
obtained. IJTOLL also computes the latitude angle using various ratios and some simple
trigonometry.

The equations governing the relation between i and j coordinates and latitude and
longitude follow.

The distance from the point to the pole (in units of grid points) was derived from the
Pythagorean theorem and is defined as:

                                                    2               2
                       POLDIS=         | CENTI- RI | + | CENTJ- RJ |

The angle (in degrees) governing the latitude can easily be derived using the diagram of
the Earth's cross-section in Figure A-1, and is defined as:



                                             A-2         NOAA POD Guide - Jan. 2002 Revision2
                                                  POLDIS 
                              ANG 1 =  = arctan         
                                                  SCALE 

The angle (in degrees) governing the longitude is also easily derived from the diagram of
a Polar Stereographic map and the i, j coordinates array in Figure A-2, and is defined as:

                                             (CENTJ- RJ) 
                             ANG 2 = arccos              
                                             POLDIS 




         Figure A-2. Deriving the Longitude from Polar Stereographic Map




Thus, from Figure A-1, the latitude is:



                                           A-3         NOAA POD Guide - Jan. 2002 Revision3
                                                                      POLDIS 
         PNTLAT =  = 90  - phiALIGNL = 90  - 2 = 90  - 2 arctan         
                                                                      SCALE 


From Figure A-2, the longitude is defined as:

                             PNTLON = PRMLON - ANG 2

Subroutines IJTOLL and LLTOIJ can be used for an array containing one or two
hemispheres. For the case of two hemispheres, IJTOLL and LLTOIJ assume that they
are arranged as shown in Figure A-3. For purposes of illustration only, the array shown
is dimensioned as two 512 x 512s or one 512 x 1024.

These equations make up the algorithm for converting from i, j coordinates to latitude
and longitude of a point. There is one special case where these equations blow up, which
happens when the point is at a pole. This makes POLDIS=0.0 and is handled by setting
the latitude to




                                          A-4         NOAA POD Guide - Jan. 2002 Revision4
          Figure A-3. Layout of Mapped Polar Stereographic Hemispheres.

+/-90 and the longitude to the prime longitude. There are a series of tests in IJTOLL
which compensate for the longitude according to which quadrant the point resides. These
tests produce the correct longitude for both the Northern and Southern Hemispheres.

If an i, j value is input which falls outside the Earth's disk but inside the array itself, the
algorithm checks whether POLDIS exceeds SCALE. If it does not, then it sets the
latitude and longitude to -999.9.

The algorithms which LLTOIJ are based upon can easily be derived by working the
IJTOLL equations backwards. LLTOIJ computes the distance of the projected point
from the pole using the latitude angle and some simple trigonometry. In addition,
LLTOIJ computes the angular difference between the prime longitude and the longitude
of the point. These two parameters are then used to compute the i and j coordinates of
the point.




                                              A-5          NOAA POD Guide - Jan. 2002 Revision5
In Figure A-3, the upper 512 x 512 array contains the Northern Hemisphere while the
lower 512 x 512 array contains the Southern Hemisphere. Subroutine IJTOLL will
automatically return the latitude and longitude (or LLTOIJ will return the i and j
coordinates) for the Southern Hemisphere although the CENTI and CENTJ input
parameters specifically refer to the Northern Hemisphere.

The arrangement shown in Figure A-3 is not mandatory in order for IJTOLL and LLTOIJ
to function properly. For example, the data for the Northern Hemisphere could be
contained in one 512 x 512 array and the data for the Southern Hemisphere could be
contained in an entirely separate 512 x 512 array. For that case, IJTOLL and LLTOIJ
could be used for the Northern Hemisphere with the proper input arguments. IJTOLL
and LLTOIJ could also be used for the Southern Hemisphere using the same input
arguments except the prime longitude which would have to be changed. (It is assumed
that the orientation of the hemispheres with the arrays is the same as in Figure A-3.)

IJTOLL and LLTOIJ represent the i and j coordinates in such a way that the i values
represent the columns and the j values represent the rows of the array. Some of the
principal points of the Earth's disk have been labeled with their proper i and j coordinates
in parentheses in Figure A-3.

For the example in Figure A-3, the input arguments would be set as follows:

       PRMLON = +80.0
       SCALE = 256.0
       CENTI = 256.0
       CENTJ = 256.0

The input parameters can be adjusted so that IJTOLL and LLTOIJ can be applied to any
case. For example, the array for the Northern Hemisphere is a 512 x 512 array. But
unlike the case shown in Figure A-3, the Earth's disk is smaller than the boundary of the
array. There are 8 blank-filled rows at the top and 4 at the bottom. Plus, there are 4
blank-filled columns on the left and 8 on the right of the Earth's disk. In this case,
SCALE = 256.0.

CENTI = 250.0 + 4.0 = 254.0 and the CENTJ = 250.0 + 8.0 = 258.0. See Figure A-4 for
an illustration of this example.




                                            A-6         NOAA POD Guide - Jan. 2002 Revision6
     Figure A-4. Layout of Mapped Polar Stereographic Northern Hemisphere

In LLTOIJ, there is a problem with obtaining the proper i and j coordinates for any point
along the equator in the Southern Hemisphere. This is caused by the fact that the
computer represents -0.0 as 0.0; therefore, making it impossible to represent the
Southern Hemisphere equator. To obtain the approximate i and j coordinates for the
equator in the Southern Hemisphere, input a number between 0.0 and -1.0 for the latitude.
Or alternately input the latitude as 0.0, and add the value of 2 x CENTJ to the RJ value
obtained. (Adding 2 x CENTJ to RJ would give the RJ the correct value for the Southern
Hemisphere.)


       A listing of the FORTRAN code for subroutines IJTOLL and LLTOIJ follows.

   SUBROUTINE IJTOLL (PRMLON, SCALE, CENTI, CENTJ, RI, RJ, PNTLAT, PNTLON)
C THIS SUBROUTINE CONVERTS I AND J COORDINATES OF A POINT ON
C A POLAR STEREOGRAPHIC MAP TO LATITUDE AND LONGITUDE.
C
C INPUT
C PRMLON PRIME LONGITUDE OF MAP BASE IN DEGREES. CAN BE
C        EITHER POSITIVE 0-360W OR POSITIVE 0-180W AND


                                          A-7         NOAA POD Guide - Jan. 2002 Revision7
C           NEGATIVE 0-180E.
C SCALE         DISTANCE FROM POLE TO EQUATOR IN GRID POINTS.
C CENTI, CENTER OF THE ARRAY IN I AND J COORDINATES.
C CENTJ
C RI, RJ THE I AND J COORDINATE OF THE POINT TO BE CONVERTED.
C OUTPUT
C PNTLAT THE LATITUDE OF THE POINT IN DEGREES (POSITIVE
C           0-90N AND NEGATIVE 0-90S).
C PNTLON THE LONGITUDE OF THE POINT IN DEGREES WITH SAME
C           SIGN CONVENTION AS PRMLON.
          SOUTH=2.0*CENTJ
          RY=RJ
          RADDEG=0.01745329
C CHECK WHETHER POINT IS IN SOUTHERN HEMISPHERE AND ADJUST
C ACCORDINGLY.
    IF (RJ.GT.SOUTH) RJ=2.0*SOUTH-RJ
C COMPUTE THE DISTANCE BETWEEN THE POLE AND THE POINT. IF
C POLDIS IS GREATER THAN SCALE, SET PNTLAT AND PNTLON TO
C -999.9 TO INDICATE AREA OUTSIDE OF EARTH'S DISK. IF POLDIS
C EQUALS SCALE SET PNTLAT AND PNTLON EQUAL TO A POLE.
   POLDIS=SQRT(ABS(CENTI-RI)**2.0+ABS(CENTJ-RJ)**2.0)
    IF (POLDIS.GT.SCALE) GO TO 50
    IF (POLDIS.EQ.0) GO TO 30
C COMPUTE PNTLAT AND PNTLON FROM ANG1 AND ANG2, THEN ADJUST
C PNTLAT ACCORDING TO RELATION WITH CENTER OF ARRAY.
    ANG1=ATAN(POLDIS/SCALE)
    ANG2=ACOS((CENTJ-RJ)/POLDIS)
    IF (RJ.GT.CENTJ) ANG2=ACOS((RJ-CENTJ)/POLDIS)
   PNTLON=PRMLON-ANG2/RADDEG
    IF (RI.GT.CENTI.AND.RJ.LE.CENTJ) PNTLON=PRMLON+ANG2/RADDEG
    IF (RI.LT.CENTI.AND.RJ.GE.CENTJ) PNTLON=PRMLON+ANG2/RADDEG
   PNTLAT=90.0-2.0*ANG1/RADDEG
    IF (RI.LE.CENTI.AND.RJ.LT.CENTJ) PNTLON=PNTLON+180.0
    IF (RI.GT.CENTI.AND.RJ.LE.CENTJ) PNTLON=PNTLON+180.0
    IF (RY.GT.SOUTH) PNTLAT=-PNTLAT
    RJ=RY
    RETURN
  30 PNTLAT=90.0
   PNTLON=PRMLON
    IF (RY.GT.SOUTH) PNTLAT=-PNTLAT
    RJ=RY
    RETURN
  50 PNTLAT=-999.9
   PNTLON=-999.9
    RJ=RY
    RETURN
    END

   SUBROUTINE LLTOIJ (PRMLON, SCALE, PNTLAT, PNTLON, CENTI, CENTJ, RI, RJ)
C THIS SUBROUTINE CONVERTS LATITUDE AND LONGITUDE OF A POINT
C ON A POLAR STEREOGRAPHIC MAP TO I AND J COORDINATES.
C
C INPUT
C PRMLON PRIME LONGITUDE OF MAP BASE IN DEGREES. CAN BE
C        EITHER POSITIVE 0-360W OR POSITIVE 0-180W AND
C        NEGATIVE 0-180E.



                                       A-8        NOAA POD Guide - Jan. 2002 Revision8
C SCALE       DISTANCE FROM POLE TO EQUATOR IN GRID POINTS.
C CENTI, CENTER OF THE ARRAY IN I AND J COORDINATES.
C CENTJ
C PNTLAT THE LATITUDE OF THE POINT TO BE CONVERTED
C         IN DEGREES (POSITIVE 0-90N AND NEGATIVE 0-90S).
C PNTLON THE LONGITUDE OF THE POINT TO BE CONVERTED
C         IN DEGREES WITH SAME SIGN CONVENTION AS PRMLON.
C
C OUTPUT
C RI       THE I COORDINATE OF THE POINT.
C RJ       THE J COORDINATE OF THE POINT.
C
    SOUTH=2.0*CENTJ
    RADDEG=0.01745329
C COMPUTE THE DISTANCE OF THE PROJECTED POINT FROM THE
C POLE.
    ANG1=(90.0-ABS(PNTLAT))*RADDEG/2.0
   POLDIS=SCALE*TAN(ANG1)
C COMPUTE THE DIFFERENCE IN RADIANS BETWEEN THE PRIME
C LONGITUDE AND THE LONGITUDE OF THE POINT.
    ANG2=(PRMLON-PNTLON)*RADDEG
C COMPUTE THE I AND J COORDINATES OF THE POINT (RI AND RJ).
    RI=CENTI+POLDIS*SIN(ANG2)
    IF(PRMLON.LT.0.0) RI=CENTI-POLDIS*SIN(ANG2)
    IF(PNTLAT.LT.0.0) GO TO 10
    RJ=CENTJ+POLDIS*COS(ANG2)
    RETURN
  10 RJ=CENTJ-POLDIS*COS(ANG2)
    IF(PNTLAT.LT.0.0) RJ=RJ+SOUTH
    RETURN
    EN




                                      A-9       NOAA POD Guide - Jan. 2002 Revision9
Appendix B:           Unpacking LAC/HRPT Data

This appendix describes a user procedure for unpacking five channel LAC/HRPT data
received on CCTs from SSB. This procedure can be readily adapted to selected channel
format LAC/HRPT data or GAC data.

As described in Section 3.2, LAC/HRPT data are written on tape as two physical records
per scan. Each scan contains data from all five channels plus Earth location and
calibration information. The data are 10-bit samples. Data from the 5 channels are
interleaved, i.e., the first data sample in the scan is from Channel 1, the next from
Channel 2, then Channel 3, Channel 4, and Channel 5, with this sequence repeating
through the scan. The 10-bit data samples are packed three to a four-byte (8 bits/byte)
group (i.e., three to a 32-bit word).

The unpacking procedure described below unpacks the data and rearranges it so that data
from the same channel are collected together and stored in sequence (i.e., all of the data
for Channel 1 followed by all of the data for Channel 2, etc.). Thus, the original five
channel scan is sorted into five consecutive single channel scan lines. The individual 10-
bit data samples are also unpacked and stored in consecutive pairs of bytes (or 16-bit
words, or 32-bit halfwords). Access to Earth location and calibration information is also
provided.

The procedure will be outlined in a sequence of steps:

1.     Define four arrays to be used as data buffers.

       a.      ISCAN (3700 @ 32 bits) - This buffer will hold a complete Earth scan (2
               physical records) of unpacked HRPT data.

       b.      IEARTH (102 @ 16 bits) - This buffer will contain the Earth location
               information.

       c.      IDATA (2048, 5 @ 16 bits) - This buffer will contain the unpacked 2048
               data samples for each of five channels.

       d.      IBUF (10242 @ 16 bits) - This buffer will hold data at an intermediate
               point in the procedure.

2.     Equivalence IEARTH(1) and ISCAN(27). This "points" IEARTH to that portion
       of the Earth scan containing the Earth location information.

3.     Skip the first three records on the tape (the first is the TBM Header record and the
       next two are the data set header records).

4.     Read the next record into ISCAN(1) through ISCAN(1850). This is the first half
       of an Earth scan.



                                           B-1           NOAA POD Guide - Jan. 2002 Revision1
5..      Read the next record into ISCAN(1851) through ISCAN(3700).            This is the
         second half of an Earth scan.

6.       The Earth location information is now available in IEARTH as described in the
         Level 1b format. For example, IEARTH(1) and IEARTH(2) are the latitude and
         longitude respectively for the first reference point (#25). To convert to units of
         degrees, divide each by 128.

7.       The calibration coefficients are now available in ISCAN(4) through ISCAN(13),
         as described in the Level 1b format. The use of these calibration coefficients is
         described in Section 3.3.

8.       Use subroutine UNPK10 to unpack the 10-bit data samples into 16-bit elements of
         IBUF. A listing of UNPK10 is included below. The FORTRAN call is:

         CALL UNPK10(ISCAN(113),IBUF,3414)

         where ISCAN(113) is the start of the HRPT data in ISCAN, IBUF is a temporary
         buffer for the unpacked but still interleaved data samples, and 3414 is the
         number of 32-bit elements of ISCAN from each of which UNPK10 will extract
         three data samples (and store them in three 16-bit elements of IBUF).

9.       Move data samples from IBUF into IDATA so that data from each channel can be
         separately accessed (i.e., IDATA(N,1) will refer to the Nth sample along the scan
         line for Channel 1, IDATA(N,2) for Nth sample for Channel 2, etc.). This is done
         by the following FORTRAN loop:

        DO m I = 1, 5   (5 Channels)
        K=I
        DO m J = 1, 2048 (2048 Samples/Channel)
        IDATA(J,I) = IBUF(K)
      m K=K+5

10.      The 10-bit data values are now accessible in IDATA as desired, concluding the
         procedure.

In the case of two channel selected data (i.e., where the user has specified that data from
only two designated channels were to be provided) UNPK10 is not used because the data
samples have already been unpacked into 16-bit elements. In the case of either one or
two channel selected data, the references to the calibration and Earth location information
are as shown.

In the case of five channel GAC data, the procedure may be used as shown with changes
for the record length and position and amount of the Earth location information.

A listing of UNPK10 follows:

         SUBROUTINE UNPK10(ISCAN,IBUF,N)



                                              B-2       NOAA POD Guide - Jan. 2002 Revision2
       DIMENSION ISCAN(3700), IBUF(10242)
       DATA MASK1/Z3FF00000/
       DATA MASK2/Z000FFC00/
       DATA MASK3/Z000003FF/
       J=0
       DO 10 I = 1,N
       IWORD = ISCAN(I)
       J=J+1
       JWORD = LAND(IWORD,MASK1)
       IBUF(J) = SHIFTR(JWORD,20)
       J=J+1
       JWORD = LAND(IWORD,MASK2)
       IBUF(J) = SHIFTR(JWORD,10)
       J=J+1
       IBUF(J) = LAND(IWORD,MASK3)
 10    CONTINUE
       RETURN
       END

The arrays used in UNPK10 are defined as follows: ISCAN is the input Earth scan
buffer, 3700 @ 32-bit elements for LAC/HRPT. IBUF is the output buffer for unpacked
data elements, 10242 @ 16-bit elements for LAC/HRPT. N is the number of elements of
ISCAN to be unpacked, 3414 for LAC/HRPT.

MASK1 is a 32-bit mask with ones set in the 10-bit positions of the first 10-bit data
sample in a 32-bit element of ISCAN. MASK2 and MASK3 are the same for the second
and third data samples.

The function LAND(A,B) performs a logical "AND" on A and B, with the result left in
A. The effect in this routine of the use of LAND and the MASK is to zero all bits in
IWORD except those of the data sample specified by the MASK, thus isolating it.

The function SHIFTR(A,N) performs a right shift of the contents of A by N places, and is
equivalent to a division of A by 2N. The purpose of UNPK10 is to right justify the
isolated data sample in IWORD, preparatory to moving it to the output buffer IBUF.

UNPK10 proceeds through the input scan buffer, unpacking the words one by one and
storing in IBUF the three data samples obtained from each input element, until the entire
input scan has been processed.




                                            B-3        NOAA POD Guide - Jan. 2002 Revision3
Appendix C:            Field Station HRPT Data Format

HRPT data are collected by two NESDIS Field Stations (Wallops Island, VA; and
Fairbanks, AK). This data is not routinely archived by SSB and is only available by
request from SSB. (SSB has to order the data from these field stations). The user should
be aware that these tapes do not contain any earth location data and the data are only 8-
bits.

The Field Station HRPT tapes contain data from only three of the AVHRR channels.
Normally, there is one tape produced from each pass, containing channels 1, 2 and 4.
The data are interleaved on a scan line by line basis; i.e., each physical record on the tape
contains data from a single channel, so that on the tape there is a record of Channel 1 data
followed by a record of Channel 2 data, followed by a record of Channel 4 data for the
first scan, and so on for other scans. Each physical record is 2048 bytes long, and each
byte contains the eight most significant bits of the original 10-bit data element. (The two
least significant bits are dropped, with resultant loss in precision of the HRPT data. For
the IR channels, this causes a loss in precision of from about 0.1 degrees for the full 10-
bit data to 0.4 - 0.5 degrees for the 8-bit data.)

Each tape contains a maximum of 13 minutes worth of data. The normal pass length is
11 minutes.

The first record on the tape is a header record, which is followed by up to 5000 data
records. The layout of these records is described below. Table C-1 depicts the header
record layout. The band numbers (Band #1, Band #2, Band #3) contain the numbers of
the AVHRR channels for which data is actually present on the tape, and in the sequence
in which they will appear. These are normally channels 1, 2 and 4, but may vary. The
time is the UTC time of the first scan written to tape.

                     Table C-1. Field Station Header Record (ASCII).
   Byte #     # of Bytes                              Contents
    1-3            3     Station ID (WAL for Wallops Island, VA or GIL for Fairbanks,
                         AK)
      4-5          2     Blank filled
       6           1     Band #1 (AVHRR Channel #)
       7           1     Band #2 (AVHRR Channel #)
       8           1     Band #3 (AVHRR Channel #)
     9-10          2     UTC time of first scan (hours)
    11-12          2     UTC time of first scan (minutes)
    13-14          2     UTC time of first scan (seconds)
    15-16          2     Duration in minutes
    17-18          2     Duration in seconds
    19-23          5     Orbit number
      24           1     Blank filled
   25-138         16     Zero filled



                                            C-1         NOAA POD Guide - Jan. 2002 Revision1
Table C-2 depicts the data record layout. The Band byte contains the AVHRR channel
number of the data contained in the data record. The telemetry data consist of each value
stored in one byte, while the back scan, space view, and space data have each of their
values stored in two bytes. The video data consist of 2048 points, each point composed of
one 8-bit byte. (Like the Level lb HRPT/LAC data, there are 2048 points in a scan.)

                            Table C-2. Field Station Data Record.
       Byte #              # of Bytes                           Contents
         1-4                    4          Scan line number in binary
          5                     1          Band (AVHRR Channel #) in ASCII
         6-8                    3          Julian day in ASCII
        9-10                    2          Hours (UTC time of scan) in ASCII
       11-12                    2          Minutes in ASCII
       13-14                    2          Seconds in ASCII
       15-24                   10          Telemetry (average) in binary
       25-30                    6          Back scan (average) in binary
       31-40                   10          Space view (average) in binary
       41-90                   50          Space data (raw) in binary
      91-2138                 2048         Video data in binary
     2139-2236                 98          Zero filled

For example, the first 24 bytes of a tape might be: "WAL 1242048401100 1690", which
would be a Wallops tape, with data from Channels 1, 2, and 4, with the time of the first
scan being 20 hrs, 48 min, 40 sec. Z, with a duration of 11 min., 0 sec., on Orbit 1690.




                                          C-2         NOAA POD Guide - Jan. 2002 Revision2
Appendix D:                 Polar Orbiter Archived TOVS Sounding Data Change
                      and Problem Record

As a user you should be aware of the following when utilizing the data. When a problem
has only a date corrected, the absence of a beginning date indicates that the problem was
in the system from launch and all previous data were impacted.

Problem and Time Period that Data were Affected

January 1, 1979
TIROS-N data available. Experimental tropopause temperature and pressure. All data
affected. Experimental total ozone. All data affected.

March 2, 1979 - March 16, 1979
Abnormally high number of cloudy (lower quality) retrievals.

January 1, 1979 - January 17, 1979; March 1, 1979 - April 11, 1979
Larger than normal errors in 100-500 mb water vapor retrievals.

January 1, 1979- February 11, 1979; March 1, 1979 - April 22, 1979
Bad atmospheric temperatures above 115 mb in the regions 74N latitude poleward and
74S latitude poleward.

May 5, 1979
Warm bias in TOVS soundings in the 55 -70 S latitude region due to seasonal transition;
coefficients adjusted and the bias eliminated.

July 13, 1979, 1200Z
Low level cloud contamination in TIROS-N clear soundings corrected.

July 1, 1979- August 3, 1979; July 13 1979 1500Z- 1700Z; July 24, 1979 1400Z - 1600Z;
July 29, 1979 1300Z - 1500Z; August 1, 1979 0900Z - 1130Z
Some mislocated data resulting in erroneous soundings; specific orbits containing bad
data.

August 22, 1979, 1100Z
Improved model for water vapor correction of TIROS-N HIRS/2 window channels
implemented.

August 27 1979, 1800Z
Increased tape recorder overlap from 4.5 minutes to 5 minutes to eliminate Eastern
Pacific data gap.

September 17, 1979, 1800Z
Increased tape recorder overlap from 5 minutes to 6 minutes to eliminate Eastern Pacific
data gap.



                                          D-1         NOAA POD Guide - Jan. 2002 Revision1
September 18, 1979, 1300Z
Implemented brightness temperature interpolation error correction into TOVS retrieval
module.

October 4, 1979
Improved water vapor attenuation coefficients for window channels for both TIROS-N
and NOAA-6.

October 9, 1979
Adjusted TOVS preprocessor to improve surface temperature handling along coastlines.

October 14, 1979
Implemented change to preprocessor to compensate for TIROS-N channel 1 calibration
problem. Products lost over weekend of October 14, 1979.

October 16, 1979, 1200Z
Began routine transmission of NOAA-6 data, doubling the number of soundings each
day. NOAA-6 data above the 3 mb level is inconsistent with TIROS-N - use with caution.

October 16, 1979
Modified correction for TIROS-N HIRS/2 channel 1 problem in preprocessor.

November 5, 1979, 0713Z Orbit 5470
TIROS-N spacecraft switched from nominal attitude control mode to the yaw gyro
compassing Mode. A maximum possible Earth location error of 70 km may have
occurred for soundings located farthest from nadir during the problem period (November
5, 1979 - November 8, 1979).

November 8, 1979, 1523Z Orbit 5517
TIROS-N spacecraft switched from yaw gyro compassing mode to nominal attitude
control mode.
November 19, 1979 - December 20, 1979
NOAA-6 soundings may be inconsistent with TIROS-N derived soundings due to
coefficient tuning and should be used with caution. Table D-1 contains missing TIROS-
N datasets due to hardware problems.

    Table D-1. Missing TIROS-N datasets between November 19 - December 20, 1979.
        Date Start Time              Date End Time             Missing Minutes
     November 23, 2054Z           November 23, 0203Z                 310
     November 24, 2035Z           November 24, 2219Z                 105
     November 25, 0156Z           November 25, 0334Z                  99
     November 25, 1538Z           November 25, 2359Z                 502
     November 26, 0328Z           November 26, 1521Z                 714
     November 27, 1516Z           November 27, 1652Z                  97
     November 27, 2001Z           November 28, 0449Z                 529
     November 28, 0642Z           November 28, 1321Z                 400


                                         D-2         NOAA POD Guide - Jan. 2002 Revision2
      November 28, 1505Z                  November 28, 1807                     183
 Total Amount of Missing Data:     2939

December 6, 1979
MSU Channel 3 removed from NOAA-6 processing by changing TARM and
coefficients. Some quality reduction expected in cloudy soundings (those without water
vapor data).

January 20, 1980, Orbit 6548
TIROS-N onboard computer failed; last processed data from TIROS-N.
TIROS-N January 23, 1980; NOAA-6 January 24, 1980
Special change for total ozone, SSU transmittances, limb corrections, and upper level
temperature coefficients; suggested by Dr. Pick of U.K.

January 27, 1980 Orbit 6635
TIROS-N normal attitude control re-established.

January 29, 1980 Orbit 6674
Sounding instruments restarted.

January 30, 1980
Restarted TIROS-N processing but only for coefficient update; no products to the world.

February 13, 1980, 1200Z
Implemented screen for precipitating clouds in the case of 3rd path sea soundings; both
TIROS-N and NOAA-6.

February 20, 1980
NOAA-6 data gaps due to hardware problems.

February 27, 1980, 1200Z
TIROS-N data again available (in addition to NOAA-6).

February 29, 1980
TIROS-N soundings were not being sent beginning this date.

March 2, 1980, 0400Z; March 4, 1980, 0000Z
NOAA-6 sounding mislocated; do not use.

March 25, 1980, 1200Z
TIROS-N sounding data again available.

April 4, 1980
Possible data gaps due to hardware problems.

May 5, 1980, 1600Z


                                           D-3        NOAA POD Guide - Jan. 2002 Revision3
Stopped TIROS-N processing.

June 10, 1980, 0950Z
Implemented new clear radiance algorithm (TARM2) (Improved cloud determination
technique) to NOAA-6.

NOAA-6 June 23, 1980, 1300Z- June 24, 1980, 1800Z; TIROS-N June 23, 1980,
1200Z - June 24, 1980, 2300Z
No TOVS soundings processed due to hardware problems.

July 7, 1980
Due to nature of the sounding technique utilized, a degradation in the third path, cloudy
soundings over sea areas in the 30 to 60 N latitude belt, especially during the winter and
summer periods and primarily below 700 mb, has been noted.

July 10, 1980
TOVS preprocessor changed to include quality control of raw data and gross limits.

July 14, 1980
Reintroduced MSU Channel 3 for NOAA-6 and corrected the TIROS-N coefficient
problem with excessive superadiabatic soundings.

July 15, 1980
Introduced corrected TARM2 module which includes a bad data protect feature and
removal of the N* surface temperature check.

July 24, 1980
Updated NOAA-6 coefficients to correct oversight when reintroducing MSU Channel 3;
coefficient changed - HIRS and MSU limb correction, water vapor attenuation, upper
level temperature regression (normally never updated).

July 25, 1980, Orbit 5599
N. Phillips correction to NOAA-6 NMC third path soundings between 30 N and 60 N
latitude over water became operational.

August 5, 1980, 1200Z
Began transmission of TIROS-N derived soundings (N. Phillips correction not included);
data volume should be increased about 70% (not doubled because of onboard computer
problems).

August 22, 1980, 2200Z - August 24, 1980, 0500Z
Some TIROS-N soundings mis-Earth located due to major spacecraft attitude problems.

August 28, 1980
N. Phillips correction applied to TIROS-N.




                                           D-4          NOAA POD Guide - Jan. 2002 Revision4
September 10, 1980, 1430 for NOAA-6; 1830 for TIROS-N
Empirical correction for MSU scan bias; both TIROS-N and NOAA-6.

September 24, 1980
Incorrectly Earth located TIROS-N soundings. 1825Z - September 25, 1980, 0400Z

October 27, 1980, Orbit 10509/10 for TIROS-N, Orbit 6936/37 for NOAA-6
Sporadic timing problem resulted in 256 second data gap in TOVS data sets.

October 31, 1980, 1538Z - 11/01/80, 2000Z
Yaw control problems for TIROS-N; Yaw errors were as large as 6.6 degrees.

November 3, 1980, 2147Z -
TIROS-N SSU out of sync and unusable.

November 20, 1980, 1952Z - November 21, 1980, 0926Z
NOAA-6 soundings lost due to calibration parameter input data problems.

November 24, 1980, 0600Z - November 25, 1980, 0600Z
Very bad Earth location for NOAA-6 (only some of the affected data transmitted).

December 31, 1980, 8 hours beginning about 0400Z
Missing Earth location data for both TIROS-N and NOAA-6.

January 13, 1981, 0800Z - 1000Z for TIROS-N, 0600Z - 1000Z for NOAA-6
Incorrect year (included as 1980).

January 5, 1981
Placed rainfall test into preprocessor for TIROS-N.

January 13, 1981
Removed rainfall test from TRET for TIROS-N.

January 26, 1981
Moved rainfall test from TRET to preprocessor for NOAA-6.

January 27, 1981, 1000Z - 01/28/81, 0800Z
TIROS-N orbit numbers "confused"; actual data not impacted.

February 17, 1981
Rainfall test corrected in preprocessor.

February 27, 1981, 1430 - 1600Z Orbit 12248
Severe attitude problems for TIROS-N; terminated as operational spacecraft.

March 5, 1981



                                           D-5        NOAA POD Guide - Jan. 2002 Revision5
Reintroduced screening of rainfall contaminated third path soundings in TRET.

March 26, 1981
MSU scan bias correction inadvertently removed from TOVS processing; reimplemented
as of March 26, 1981.

April 7, 1981, 1500Z
SATEM soundings (for 30N - 65N, oceanic, microwave only soundings) height values
modified to remove a continental bias.

April 7, 1981
Changed procedure to determine superadiabatic retrievals in TRET; checked only
mandatory levels; fewer products rejected.

April 9, 1981
Rainfall test moved from TRET to preprocessor.

April 9, 1981
Spring ozone coefficients copied into coefficient data base.

April 9, 1981 - April 20, 1981
Surface temperature test unintentionally removed; larger than normal errors in the
sounding product below 700 mb may occur in a few cases.

May 4, 1981
Began interactive operational tests; lower quality soundings marked on archive.

June 10, 1981
Summer ozone coefficients introduced.

June 30, 1981
More maritime samples in the 30 to 60N latitude zone for coefficient tuning; also,
interactively rejected soundings no longer allowed in the coefficient sample.

July 9, 1981
Skin Temperature no longer contains the observed Channel 8 value for clear and N*
soundings. From this time parameter will always contain the first guess surface
temperature from mapped internal field.

August 14, 1981
NOAA-7 soundings became operational and were added to the archive tapes.

September 18, 1981
The quality of NOAA-6 soundings was decreased due to increased noise from the August
28, 1981 AVHRR.




                                           D-6         NOAA POD Guide - Jan. 2002 Revision6
September 10, 1981
A change was made to utilize the sea surface temperature as a predictor for low level
third path cloudy soundings over ocean.

October 21, 1981
Implementation of a new clear radiance test to better discriminate low level clouds. This
change will reduce the number of N* retrievals and increase the third path, cloudy,
soundings.

November 3, 1981
A change was made that inadvertently deleted all third path products below 100 mb over
water.

November 8, 1981 - November 12, 1981
The problem from Nov. 3 was corrected. A small change to the coefficient system was
made to improve the third path product over the Antarctic plateau.

November 28, 1981
Clear radiance module (TARM) and the retrieval module (TRET) were changed.

January 8, 1982
TARM2 (clear radiance) was changed to increase a limit for one of the clear window
channel comparison tests in the 30 N - 30 S latitude region at night.

February 18, 1982
Coefficient change made which eliminated MSU channel 3 as a predictor for water vapor.

August 16, 1982
Radiance module (TARM2) was changed. The number of partly cloudy soundings (N*)
will be reduced, and the number of cloudy soundings (third path) will increase by 3 to
4%.

October 1, 1982
Problems with the TOVS soundings over Antarctic, especially above 100 MB. The
problem was caused by the annual spring (southern hemisphere) stratospheric warming.

November 17, 1982
The TOVS preprocessor was modified to compensate for an instrument mirror coating
problem affecting channel 10 of the HIRS.

December 16, 1982-1458Z to December 17, 1982-1441Z
All soundings have bad information at all levels above 100 mb. The lower levels are
good.

December 1, 1982 - January 4, 1983




                                          D-7          NOAA POD Guide - Jan. 2002 Revision7
There was a significant increase in the noise in channels 1 through 12 for the NOAA-6
satellite. By Jan. 4, the noise was back to normal.

December 2, 1982 - February 17, 1983
The percent of cloudy soundings from the NOAA-6 spacecraft increased from 35% to
50%. Noisy HIRS data and improper water vapor attenuation coefficients are causing the
problem.

January 13, 1983
Channel 9 limb correction changed. It should only affect the ozone products.

January 27, 1983
A new scheme for determining the existence of water droplets in clouds was placed into
the TOVS preprocessor.

February 17, 1983
Water vapor attenuation coefficients changed for NOAA-6.

March 2, 1983
New channel 9 coefficients implemented.

April 17, 1983 - June 19, 1983
Only 62% of the NOAA-6 data was processed due to the checkout of the new NOAA-8
spacecraft.
June 20, 1983
NOAA-6 sounding products terminated.

June 20, 1983
NOAA-8 became operational. Soundings on the archive tapes for this satellite will have
a SAT ID of 3, but the Raw Level 1B data will have a SAT ID of 6.

August 5 (2019Z) to August 7, (0119Z) l983 for NOAA-7
August 5 (1918Z) to August 7, (0256Z) l983 for NOAA-8
Water and a power outage caused a shut down of the NESDIS computer. There were no
TOVS data processed during the above periods.

September 1, 1983
SSU channel 2 turned off for NOAA-7. Recalculated the upper level temperature
regression coefficients without using SSU channel 2 of NOAA-7. Use SSU Channel 2
data from NOAA-8 to replace failed NOAA-7 SSU channel 2.

September 8, 1983
The surface elevation file and land/sea tags were modified to reflect the Air Force
topography data for the area between 85 - 60N Latitude and 70 and 14W Longitude.

September 15, 1983



                                          D-8         NOAA POD Guide - Jan. 2002 Revision8
SSU channel 3 data from NOAA-8 started showing increased noise. Some orbits of
TOVS soundings are being produced without SSU data.

September 20, 1983
A new Greenland Elevation field and land/sea tags were implemented into the TOVS
processing system.

September 26, 1983
A change was made in the SEL software to allow all SSU data to pass through to the
TOVS processing system. SSU channel 3 still shows increased noise.

October 11, 1983
The HIRS channel 7 and 8 order test has been implemented in TARM 2. The new test
will prevent bad spots from going into the N* estimation procedure. This procedure
reduced the percentage of N* by 1%.

October 20, 1983
Subroutine HIR8LM was modified to limb correct the HIRS channels 8 and 10 used in
the water vapor attenuation correction of channel 8.

November 8, 1983
Subroutine NEARRS, which calculates distances between RAOBS and retrievals, had an
error when computing longitudinal distance across the International dateline. Error
corrected November 8, l983.

November 17, 1983
A subroutine has been written and tested to handle a permanent direct access read error
on the DSD3 and DSD5 files.

December 7, 1983
The quality of SSU channel 3 data on NOAA-8 has deteriorated to the extent that it needs
to be turned off from the processing system. Channel availability flag for SSU channel 3
was turned off.
January 12, 1984
Subroutine CLEAR was modified to read the bi-directional reflectance table as a function
of solar zenith, solar azimuth, and satellite zenith angles if over ocean areas during the
day. This test improved our albedo measurements over ocean areas.

February 23, 1984
Improved upon the redundant orbit check routine so that operator does not need to mark
the orbits every time a data set fails.

March 20, 1984
Dewpoint temperature correction - uses uncorrected dewpoint depression data to compute
water vapor. Subroutines modified: SETUP and RAOBTW.




                                           D-9         NOAA POD Guide - Jan. 2002 Revision9
April 13, 1984
Surface elevation change - new land/sea tags and elevation files were generated and
placed in the Coefficient Data Base (CDB).

April 16, 1984
$TUFOA - changed to extract data from the TOVS soundings rather than the
enhancement data.

May 7, 1984
Subroutine TOPOG2 changed to add new surface elevations between 87 S and the South
Pole.

May 23, 1984
Atmospheric Transmittance coefficients were modified. This proved to be the change
with the most improved impact on the TOVS operation. Cloudiness percentages dropped
on NOAA-7 from 52% to 32% and the quality of clear soundings improved dramatically.

June 20, 1984
(TOVS) SSU channel 2 data turned off effectively on June 19 after NOAA-8 began
experiencing operational problems. NOAA-7 became the only operational space- craft to
produce TOVS soundings after NOAA-8 was turned off in late June.

July 2, 1984
New cloud algorithm better estimates cloud top temperature, cloud amount (in percent)
and cloud albedo.

September 25, 1984
New NOAA-6 processing modules were produced to process the NO-HIRS data from
NOAA-6. The modules modified are: 1) Preprocessor; 2) $TARM2; 3) $TRET; 4)
Radiosonde Match; 5) CFLTR and 6) COFRET. Comparisons between NOAA-6 and
NOAA-7 soundings showed compatibility at all levels but the surface and tropopause.

November 19, 1984
Stratospheric Smoother Algorithm corrected to provide more consistent stratospheric
temperature fields at the 15, 5, and 1mb levels. Subroutine FIVEPT changed in module
SSUSMOTH.

November 26, 1984
Land/Sea tag change for NOAA-6 was made to reflect earlier, similar changes made for
NOAA-7 and NOAA-8.

February 2, 1985
NOAA-7 HIRS filter wheel began malfunctioning on February 5. HIRS turned off
completely on February 7. The NOAA-6 NO-HIRS modules were swapped into the Sat
1 (NOAA-7) operation and we began producing NOAA-7 NO-HIRS data on February 8.




                                        D-10         NOAA POD Guide - Jan. 2002 Revision10
February 25, 1985
NOAA-9 becomes operational. TOVS now running on one system of processing
modules that can handle NO-HIRS processing as well as regular (HIRS, MSU, and SSU)
TOVS data.

March 21, 1985
Incorporated new program to periodically check and update HIRS and MSU
transmittance functions (gamma coefficients).

June 5, 1985
Change radiosonde match and coefficient filter routines to allow for a satellite ID greater
than 4.

July 26, 1985
Check mode in the radiosonde match network to prevent super-adiabatic and skin
temperature retrievals from being saved on the DSD5 file.

August 22, 1985
Input change to use SST values for NOAA-8 (NO-HIRS) oceanic soundings to increase
accuracy of NOAA-8 lower level soundings.

October 24, 1985
Corrected the zonal coefficient interpolation for latitude zone 1 (North Polar region) by
preventing any use of zone 2 coefficients in zone 1 above 70 North latitude.

November 22, 1985
Turned off the frozen sea test and the surface temperature test poleward of 50 latitude.
Change made to Atmospheric Radiance module (TARM).

December 18, 1985
Error in TARM subroutine DRIVER was found causing an extra 5% of sounding data to
be classified as N* (partly cloudy) instead of cloudy.

January 1, 1986
Problem encountered with TOVS archived data during transition to the new year. End of
year navigation problems caused mislocated data to be archived from 1/1/86 00Z to
1/2/86 14Z. No products were archived from 1/2/86 14Z to 1/3/86 20Z.

April 4, 1986
New TRET and COFTST to change surface reference pressure level from 1000 to 1013
mb.

May 1 - August 4, 1986
Bad mapper module (TSM) installed. Destroyed SSU and surface fields.

April 15, 1986



                                         D-11          NOAA POD Guide - Jan. 2002 Revision11
New enhancement system installed.

May 6 - July 1, 1986
Archive generation problems.

May 13, 1986
Australia complained inaccurate soundings 45 S near Australia.

May 15, 1986
New TRET implemented at 12L to fix 45 S interpolation problem.

May 20, 1986
Earth Location error south of 65 S.

May 22, 1986
New water vapor transmittances for NOAA-9.

May 27, 1986
New Land/Sea tags for NOAA-9 installed at 1530L.

May 28, 1986
NWS reported discontinuity for NOAA-6 around zones 4 and 5 boundary. Lower
troposphere data suspect due to bad surface field.

May 29 - July 15, 1986
NOAA-6 south of 50 S has

June 3, 1986
First archive tape since enhancement.

June 10-11, 1986
Hardware problems at SOCC caused loss of 2 to 3 superswaths (40 HIRS scan lines each)
per orbit for both satellites.

July 1, 1986
NOAA-6 and NOAA-9 processing failed because of file problems. Problem with
NMC/NESDIS housekeeping file caused TUFON to abort from 1100L to 1930L.
Archive data during that period was lost.

July 8, 1986
ECMWF reported NOAA-9 soundings bad south of 50 S at levels above 150 mb.
Problem found to be bad coefficients.

July 9, 1986
NMC software changes caused product formatter job to fail from 1700L July 8 to 0900L
July 9. Archive data lost.



                                        D-12        NOAA POD Guide - Jan. 2002 Revision12
July 9, 1986
Losing 2 to 3 NOAA-9 orbits per day due to large data gaps in GAC transmission from
Wallops. Bad modem replaced. (Still missing data through August.)

July 7-10, 1986
Bad NOAA-9 coefficients for zones 4 and 5.
July 22, 1986
New TARM implemented to correct cloud cover algorithm.

July 29-30, 1986
Bad NOAA-9 thicknesses for Zones 4 and 5 from 15 to 20 mb because of small sample
sizes.

July 31, 1986
NMC began using NOAA-6 in operations again.

September 8, 1986
New rain filter placed in the Preprocessor.

September 17-22, 1986
Reduction in total number of soundings attributed to NOAA-9 MSU 1b Mirror Sequence
flag being set about 30% of the time. Reinstalled old preprocessor on September 17
when believed it was the cause of the low data coverage. New preprocessor restored on
September 22 when MSU 1b was found to be the problem.

September 24, 1986
Two NOAA-6 orbits failed due to data gaps.

October 21, 1986
Preprocessor change installed for NOAA-9 proper data scaling factor from CDB.

October 23, 1986
New Radiosonde correction method (RADCOR) implemented.

November 3, 1986
New archive module installed to fix data shuffling and delete problems.

November 3-5, 1986
Cold bias above 200 mb caused by double correction to radiosondes.

November 7, 1986
Due to instrument problems on NOAA-6 and NOAA-9 data no longer sent to users.
Archive continued. Problems believed to be due to solar flare.
       NOAA-9 HIRS noisy
       NOAA-9 MSU channel 3 - major hit opened limits



                                         D-13        NOAA POD Guide - Jan. 2002 Revision13
       NOAA-6 MSU channels 1 and 2 opened limits on October 31, 1986

November 10, 1986
NOAA-6 processing stopped.

November 13, 1986
NOAA-9 data near normal.

November 14, 1986
Trouble may be continuing with scan sequence flag. Started seeing reduced number of
soundings.

November 18, 1986
Put in corrected preprocessor to take care of MSU mirror sequence error flag.

December 4, 1986
Erratic NOAA-9 MSU channel 3 behavior. Causing reduced sounding accuracy at 250 to
300 mb.

January 1-2, 1987
Earth Location problems from 5Z January 1 to 5Z January 2. Data mislocated.

January 7, 1987
NOAA-10 activated.

January 8-12, 1987
Increase in number of cloudy retrievals believed due to noisy HIRS for NOAA-9. On
January 12 new HIRS calibration limits were applied. Percent cloudy retrievals reduced
possibly because of drop in HIRS channel 1 noise.

February 3, 1987
NOAA-9 MSU channel 3 performance significantly deteriorated, resulting in large
temperature biases about 250 mb.

February 5, 1987
Three NOAA-9 orbits missed due to noise.

February 9, 1987
Three NOAA-9 orbits missed due to noise and orbital processing problems.

February 20, 1987
NOAA-9 HIRS noise level unstable and generally increasing since about January 5, 1987
resulting in reduced retrieval accuracy.

February 25, 1987




                                        D-14         NOAA POD Guide - Jan. 2002 Revision14
Reset limits have been placed on NOAA-9 MSU channel 3 input data to filter noisy data
from retrieval processing. Filtering process will result in missing NOAA-9 retrieval
coverage when the MSU is unstable.

February 26, 1987
NOAA-9 HIRS noise high again.

March 4, 1987
Three NOAA-9 orbits missed due to noisy MSU channel 3.

March 6, 1987
No NOAA-9 processing from 14Z to 18Z due to no NOAA-9 MSU.

March 7, 1987
NOAA-9 MSU channel 3 unusable.

March 9, 1987
Discontinued sending NOAA-9 data to users. The failure impacted NOAA-10 retrieval
accuracy at 10 mb and above as NOAA-9 SSU was being used for NOAA-10.

March 10, 1987
Modified NOAA-9 processing to produce SSU for NOAA-10.

March 10, 1987
NOAA-9 MSU Channel 2 failed on March 7, 1987. That coupled with the previous
failure of Channel 3 has caused the termination of the TOVS Sounding Product from
NOAA-9.

March 18, 1987
NOAA-10 quality problem above 30 mb. Soundings for NOAA-10 above 100 mb will
be discontinued.

March 26, 1987
Missing NOAA-10 HIRS data due to missing calibration coefficients.

April 8-9, 1987
From 1550L on April 8 to 10L on April 9, NOAA-9 processing was halted due to
communications problems.

April 21, 1987
NOAA-10 has warm biases at 10 mb, possibly due to coefficients.

April 21, 1987
Polar redundancy changed. TUFON was upgraded to handle filter flag changes caused
by the new polar redundancy algorithm. Problem was that the same DSD3 record was




                                       D-15        NOAA POD Guide - Jan. 2002 Revision15
being read over and over again when the last record of an orbit was not filter flagged as
good.

May 12, 1987
22% NOAA-9 coverage due to no HIRS calibration.

May 13, 1987
NOAA-9 missing 2 or 3 orbits between 14Z and 18Z due to noisy data.

May 16-18, 1987
Seventeen NOAA-9 orbits missing due to noisy data.

May 28, 1987
Two NOAA-10 orbits missing due to noisy transmission.

June 10, 1987
Three NOAA-9 orbits missing due to noisy HIRS.

June 18, 1987
Processing modified to accept SSU data up to 24 hours old for TRET processing.

June 21, 1987
Two NOAA-10 orbits between 16 and 19Z missing due to HIRS channel data problems.

June 23, 1987
Four NOAA-10 orbits missing due to noisy data.

June 30 - July 21, 1981
"Discovered missing coverage on NMC/NESDIS file." This is the Archive input file.
Problem in directory when first sounding is not "good".

July 9, 1987
Three NOAA-10 orbits missing due to noisy HIRS data because of a bad recorder.

July 14, 1987
Four NOAA-10 orbits missing. Data noisy due to tracking problem with NASA's 24 ft.
dish at Wallops.

July 16, 1987
Three NOAA-10 orbits missing due to noise.

July 28-29, 1987
No NOAA-10 processing from 1L July 28 to 13L July 29 due to power outage and
resulting hardware problems.

August 3, 1987



                                         D-16         NOAA POD Guide - Jan. 2002 Revision16
Six NOAA-10 data sets were lost over the past three days due to noise.

August 5, 1987
Four NOAA-10 data sets were lost due to Earth Location problems.

August 5-11, 1987
Poor quality sounding data between 350-30 mb over Antarctica due to bad radiosonde in
the Matchup data base for coefficient generation.

August 10-13, 1987
Cold bias for NOAA-10 from 100 to 50 mb over Hudson Bay due to noisy MSU channel
4. Calibration limits were tightened.

August 31, 1987
Began sending NOAA-9 HIRS only soundings to users (NMC and ECMWF).

September 9, 1987
Updated topography field and land/sea tags.

September 11, 1987
Three NOAA-10 data sets lost due to noise at Wallops Island CDA.
Seven NOAA-9 data sets lost due to HIRS noise.

September 15, 1987
Filter module upgraded at 1415Z to improve the noise and redundancy filtering to
improve the data quality and sounding spacing.

September 23, 1987
Six NOAA-9 orbits failed due to noisy HIRS.

September 28, 1987
Two NOAA-9 orbits lost due to noisy HIRS.

October 16-19, 1987
NMC/NESDIS (archive file) Housekeeping file problem. Product formatter for NMC
and Archive not working.

October 27, 1987
NOAA-9 MSU quarterly calibration.

October 28, 1987
NOAA-10 orbit 62-63 lost due to Earth Location Problems
NOAA-10 orbit 67-68 lost due to noisy HIRS and MSU
NOAA-9 orbit 08-09 and 07-08 lost due to Earth Location Problems.

December 1, 1987



                                        D-17         NOAA POD Guide - Jan. 2002 Revision17
Data mislocation checks installed at 1440Z.

January 1, 1988
NOAA-10 data not processed from 0Z to 4Z due to no Earth Location.
Three NOAA-10 orbits between 19Z December 31 and 640Z on January 1 were not
archived.

January 2, 1988
Satellite data mislocated by 1 degree East longitude from 0Z 1/1 to 4Z 1/5 (leap year
troubles).

January 7, 1988
NOAA-9 data missing due to level 1b data set problems. Orbits 15799-15800,15803, and
15806-15808.

February 2, 1988
SSU Cell pressures updated.

February 29, 1988
Gilmore Creek communication line down from 17Z February 25 to 13Z February 29.

March 9, 1988
Five NOAA-9 orbits missing. One NOAA-10 orbit missing.

March 16, 1988
Surface upgrade installed.

March 26, 1988
Four NOAA-10 orbits were missed due to no Earth Location data.

April 25, 1988
Two NOAA-10 orbits failed due to software problems.

May 4, 1988
TOVS processing down due to software problems from 14 to 22L.

May 10-11, 1988
No NOAA-10 p

July 6-8, 1988
Controller between NAS and DPSS down from 14L July 6 to 1215L July

July 13, 1988
Three NOAA-10 lost due to HIRS channel 1 missing calibration coefficients.

July 19, 1988



                                        D-18          NOAA POD Guide - Jan. 2002 Revision18
One NOAA-10 orbit missed.
August 16, 1988
Eight TOVS orbits not processed due to thunderstorm activity.

August 18, 1988
Thunderstorm activity between 3 and 630Z caused some data loss.

August 29, 1988
Three NOAA-10 orbits missed due to data problems.

September 1, 1988
One NOAA-10 orbit missed due to bad HIRS level 1b.

September 18, 1988
One NOAA-10 orbit was missed (0-2Z) due to no HIRS Earth Location.
One NOAA-10 orbit was missed (1040-1220Z) due to HIRS Channel 7 noise.

September 20, 1988
Physical Retrieval algorithm was implemented at 18Z.

September 27, 1988
Two NOAA-10 orbits were missed due to bad level 1b data sets.

October 18, 1988
Discontinued processing NOAA-9 TOVS Sounding Product.

October 19, 1988
Began using NOAA-11 SSU for NOAA-10 processing at 18Z.

October 25, 1988
NOAA-9 processing stopped at 10L.

October 26, 1988
Four NOAA-10 orbits from 630 to 1330Z were not processed due to missing HIRS
channel 1 calibration coefficients.

November 4, 1988
Three NOAA-10 orbits missed due to level 1b problems.

November 8, 1988
New SSU cell pressures implemented at 1030L.

November 14, 1988
Five hour gap in coverage due to file problems.

December 19-20, 1988



                                        D-19        NOAA POD Guide - Jan. 2002 Revision19
No NOAA-10 soundings from 15L December 19 to 8L December 20 due to software
problems.

December 20, 1988
Archive changed to run on Sunday evenings.

January 4, 1989
NOAA-11 processing became operational. Channel 10 moved to new wavelength to
better predict water vapor attenuation and to better correct channel 8. High percent of
cloudy data resulted. Channel 17 moved from stratosphere to lower troposphere.

January 7, 1989
Six NOAA-11 orbits lost due to software problem.

February 28 - March 3, 1989
Percent of cloudy NOAA-11 soundings increased. Problem corrected on March 3 at
1430Z.

March 2, 1989
Two orbits lost due to bad Earth Location.

March 16, 1989
NOAA-10 orbits 12943-46 and NOAA-11 2430-38 lost due to File Transfer problems
with the DPSS to NAS.

March 18, 1989
Power down from 1130L to 2000L.

April 5, 1989
Four NOAA-11 channel attenuation coefficients changed.
Two NOAA-10 orbits bad - 13234, 13232.

April 6, 1989
DPSS down due to hardware work from 8Z to 20Z -- some data may be lost.

April 13, 1989
New surface field update installed introduced ice field updating, changed from day/night
to warm/cold determination, channel 8 not used to update oceans.

April 25, 1989
New gammas for HIRS channels 17,24. New noise limits for MSU channels 1 to 4.

May 11, 1989
Added new words to NMC/AIDS file:
      -added minibox number
      -added sea surface temperature



                                         D-20         NOAA POD Guide - Jan. 2002 Revision20
May 16, 1989
Prohibited use of MSU channel 2 over high terrain. MSU 2 not used in Antarctica.

May 21, 1989
Four NOAA-11 orbits lost due to communications problems.

July 13, 1989
Added HIRS channel 17 to NOAA-11, added as a predictor for limb correction.

July 24 - 28, 1989
Severe thunderstorms impacted the processing of TOVS data. While Level 1b data sets
were received, many of them were too noisy to be processed. This resulted in a fair
amount of TOVS data being lost. Table D-2 contains the times of noisy data.

              Table D-2. Times of noisy data between July 24-28, 1989.
                            July 26                         1311-1456Z
      NOAA-10               July 27                    0031-0540, 1430-1740
                            July 28                   1047-1223 (No Level 1b)
                            July 24                         0915-1221Z
      NOAA-11               July 26                    1526-2131, 2203-2339
                            July 28                   0644-0822 (No Level 1b)

August 14, 1989
Three NOAA-9 and one NOAA-11 orbits lost due to thunderstorms.

August 16, 1989
New SSU cell pressures installed.

August 17, 1989
Four NOAA-10 orbits lost due to system problems.

August 18, 1989
Six NOAA-10 orbits lost due to noisy HIRS.

September 4, 1989
Three NOAA-11 orbits not processed.

September 17, 1989
Four NOAA-10 and four NOAA-11 orbits lost due to thunderstorms.

October 5, 1989
One NOAA-10 and two NOAA-11 orbits lost due to Auto Tracking problem at Wallops
Island.

November 1, 1989


                                       D-21        NOAA POD Guide - Jan. 2002 Revision21
Five NOAA-10 orbits lost due to no Earth Location.

November 30, 1989
NOAA-10 data from 1745 on November 29 to 0Z on November 30 and NOAA-11 data
from 1630 to 2330Z on November 29 were lost due to computer problems.

December 14, 1989
NOAA-10 data over 100 mb in oceanic regions suspect. Problem traced to first guess.

January 1, 1990
First three orbits in 1990 of Level 1b TOVS data lost.

January 19, 1990
Three NOAA-11 and four NOAA-10 orbits lost.

January 23-25, 1990
Sixteen orbits lost due to satellite readout problems.

February 5-7, 1990
Coefficient update generated bad NOAA-11 coefficients over land. New coefficients
generated on February 7 to correct the problem.

February 12-23, 1990
NOAA-10 and NOAA-11 poor quality due to coefficient generation problem. Fixed on
February 23.

February 26, 1990
Three NOAA-10 orbits lost due to file problems

March 13, 1990
Installed upgrade to compute cloudy coefficients from cloudy matchups.

March 13-20, 1990
Regression ozone accidentally replaced with Physical Retrieval Ozone. No NOAA-10
ozone produced because of no new coefficients.

March 28, 1990

April 10-11, 1990
No TOVS data from 1830L to 0930L due to hardware problems.

May 8, 1990
Implemented Physical Retrieval TOVS Total Ozone.

May 7-16, 1990




                                          D-22           NOAA POD Guide - Jan. 2002 Revision22
Implemented new TUFON to include cloud information for cloudy retrievals and to
remove superadiabatic and surface failure retrievals. TUFON improperly processing
TOVS data. Possible duplicates and missing data on archive tape.

June 10, 1990
Power failure, lost five NOAA-10 and one NOAA-11 orbits.

June 19, 1990
TUFON properly installed. Physical Retrieval Ozone accidentally removed.

June 22, 1990
Four NOAA-10 orbits too noisy to process.

June 28, 1990
Physical Retrieval Ozone restored to operations.

August 27, 1990
Included brightness temperatures for cloudy retrievals in the archive.

September 6-21, 1990
No NMC SST information included in file.

November 7, 1990
No archive produced November 5-6, due to file problems.

November 14-19, 1990
Tightened Radiosonde rejection requirements.

November 29 - December 3, 1990
Reduced coverage due to operational files being renamed.

December 5, 1990
Reimplemented tightened radiosonde rejection.

December 16, 1990- January 9, 1991
Missing SSU information for NOAA-10 due to problems with NOAA-11 SSU map files.

January 15, 1991
No weekly ice update performed.

January 28 - February 3, 1991
Archive data lost due to problems.

February 12, 1991
Implemented new ICE module which will not use blank data records nor place ice packs
between 45 degrees North and 45 degrees South.



                                         D-23         NOAA POD Guide - Jan. 2002 Revision23
February 19, 1991
Modified time and distance windows in radiosonde match.

March 4, 1991
Implemented improvements to the coefficient update software.

May 16, 1991
3 NOAA-11 and 4 NOAA-10 orbits missing due to poor data quality or were not received
for processing.

May 20, 1991
NOAA-10 cloudy coefficients not updated (potential bad input data).

May 23, 1991
Stability departure computation included in processing.
3 NOAA-11 orbits missing due to antenna problems at Wallops Island readout station.

May 29, 1991
Coefficients for NOAA-11 updated two days late.

May 30, 1991
Coefficients for NOAA-10 Clear and Partly Cloudy data were updated 3 days late.


June 5, 1991
Coefficients for NOAA-10 cloudy data were updated for the first time since May 20,
1991.

July 8, 1991
12 NOAA-10 orbits missing due to no earth location.

July 9, 1991
9 NOAA-10 orbits missing due to no earth location.

August 16, 1991
1 NOAA-11 orbit missing due to bad HIRS line counter
1 NOAA-10 orbit missing due to no earth location.

August 24, 1991
1 NOAA-11 orbit missing due to poor data quality.
1 NOAA-10 orbit missing due to no synchronized MSU frames.

September 4, 1991
2 NOAA-11 orbits missing due to no synchronized MSU frames and noisy data. 1
NOAA-10 orbit missing due to no earth location.



                                       D-24           NOAA POD Guide - Jan. 2002 Revision24
September 5, 1991
1 NOAA-11 orbit and 1 NOAA-10 orbit missing due to problem in 1b data set
generation.

September 16, 1991
1 NOAA-11 orbit missing due to problem in 1b data set generation. NOAA-12 became
operational with orbit start time of 1652Z. (NOAA-10 TOVS no longer processed and
archived).

September 22, 1991
1 NOAA-12 orbit missing due to problem in 1b data set generation.

September 23, 1991
New asymmetric scan bias angles for NOAA-12 MSU channels 2,3, & 4.

October 28, 1991
1 NOAA-11 orbit missing due to large HIRS data gaps.

November 6, 1991
Implemented upgrade to improve selection of partly cloudy data.

November 11-15, 1991
Sparse archive due to problems in processing system (not science or data related).

November 19, 1991
1 NOAA-12 orbit missing due to channel problems in HIRS.

November 21, 1991
1 NOAA-12 orbit missing due to bad HIRS line counter.

November 22, 1991
5 NOAA-12 and 3 NOAA-11 orbits missing due to problem in 1b data set generation.

November 23, 1991
1 NOAA-11 and 1 NOAA-12 orbit missing due to problem in 1b data set generation.

November 24, 1991
4 NOAA-11 and 4 NOAA-12 orbits missing due to problem in 1b data set generation.

December 26, 1991
Reduced volume of NOAA-12 data over Antarctica (could have been present for entire
time NOAA-12 operational) corrected. Radiance windows for HIRS channels 1 and 2
were too tight.

January 7, 1992



                                        D-25          NOAA POD Guide - Jan. 2002 Revision25
Documented steady decline in number of partly cloudy soundings for NOAA-12 since
December 31, 1991 with increase in the number of cloudy soundings. Problem found
with HIRS instrument - no data distributed or archived beginning with January 7, 1992.

January 13, 1992
Resumed processing of NOAA-12 data.

January 14, 1992
Resumed data distribution and archive of NOAA-12 data.

March 11, 1992
TOVS archive changed to save full resolution data (good and redundant data saved).

March 16-18, 1992
No NOAA-12 data processed due to change in calibration file which was incompatible to
TOVS processing.

March 19, 1992
Discontinued distribution and archive of NOAA-11 and NOAA-12 data due to bad
coefficients resulting from bad radiosonde data used as input.

March 20, 1992
Resumed distribution and archive of NOAA-11 and NOAA-12 data at 20 Z. Two
NOAA-11 and four NOAA-12 orbits missing.

April 6, 1992
Implemented upgrade to improve cloudy retrievals, particularly near the surface.
Replaced using NMC sea surface temperature with the NMC Aviation Forecast potential
temperature for first guess determination.

April 16, 1992
No weekly coefficient update was performed. One NOAA-12 orbit missing.

May 4, 1992
Eliminated zero mean layer temperatures over high terrain.
One NOAA-12 orbit missing.

May 6, 1992
Eliminated 12 hour inconsistency of SSU data for the even numbered satellite.

May 13, 1992
Eliminated housekeeping file from TOVS archive.

May 18, 1992
Metadata file moved to separate archive tape due to size constraints. 1 NOAA-11 and 1
NOAA-12 orbits missing.



                                        D-26         NOAA POD Guide - Jan. 2002 Revision26
June 13-15, 1992
No matches made with radiosondes due to change in radiosonde file by NMC.

June 15, 1992
Two NOAA-11 and one NOAA-12 orbits missing. Some of the missing NOAA-11 orbits
over the past few days are due to HIRS channel 15 having zero radiances; problem
corrected by calibration.
July 7, 1992
MSU quarterly calibration for NOAA-11 and NOAA-12. One NOAA-12 orbit missing.

August 31, 1992
Began computing TOVS Total Ozone for cloudy retrievals.

September 9, 1992
Changed coefficients used for computing TOVS total ozone.

September 15, 1992
Implemented correction to keep bad radiosonde data about 100mb from getting into the
TOVS coefficient update system. 1 NOAA-11 orbit missing.

October 20, 1992
Improved determination of cloud top temperature and cloud amount.

December 1, 1992
MSU quarterly calibration for NOAA-11 and NOAA-12.

December 5-8, 1992
A number of NOAA-12 orbits were processed 2 or 3 times causing redundant data to be
written to the archive. Processing problems also caused some NOAA-11 and NOAA-12
orbits to be missed between December 5-9.

January 4, 1993
7 NOAA-11 orbits missing.

December 30, 1992 - January 5, 1993
Many NOAA-11 orbits missing due to HIRS channels 13 and 16 space view being out of
limits; new limits set by calibration.

February 24, 1993
TOVS operational processing performed on the new NESDIS computer (CEMSCS). No
change in quality of TOVS products.

March 2, 1993
MSU quarterly calibration for NOAA-11 and NOAA-12.
One NOAA-11 orbit missing.



                                       D-27        NOAA POD Guide - Jan. 2002 Revision27
March 7, 1993
Four NOAA-11 and 3 NOAA-12 orbits missing due to power outage at the Wallops
Island CDA.

March 31, 1993
No NMC Sea Surface Temperature information available.

April 14-17, 1993
No data archived for NOAA-11 and NOAA-12 due to software problems.

April 15, 1993
Two NOAA-11 orbits missing. NOAA-11 HIRS channel 13 warm black body gross
filtering limits were adjusted.

April 19, 1993
NOAA-12 HIRS channel 7 warm black body gross filtering limits were adjusted.

May 3, 1993
NOAA-11 HIRS channel 14 warm black body gross filtering limits were adjusted.

May 7, 1993
No NOAA-11 and NOAA-12 archive data for May 4 and May 5 - data overwritten on the
archive tape.

April 28 - May 21, 1993
Fewer retrievals than normal processed for NOAA-11 because HIRS channel 1 intercept
below accepted level. Offset adjusted to make channel 1 usable.

May 26, 1993
Added check to coefficient update job to compare stability departure of radiosonde and
retrieval match pairs. If beyond limit, radiosonde not used for coefficient generation or
added to first guess library.

May 27, 1993
NOAA-12 HIRS internal target gross filtering limits were adjusted.
NOAA-11 HIRS channels 15 and 16 space view gross filtering limits were adjusted.

June 10-18, 1993
HIRS channels for NOAA-12 have increased noise, induced by vibrations from the
AVHRR instrument, for portions of some orbits. The TOVS data in those affected area
have data dropouts due to brightness temperatures being out of range and the data are
cloudy in the regions of the dropouts. (Cloudy retrievals only use the upper level HIRS
channels).

July 23-24, 1993



                                         D-28         NOAA POD Guide - Jan. 2002 Revision28
Little to no NOAA-11 data archived due to processing problems.

July 26, 1993
Observed cases for NOAA-11 where less than 10 scans of data in an orbit were bad due
to anomalies in the MSU values. (Occurrences very infrequent)

July 29, 1993
NOAA-11 MSU PRT target temperature and slope limits were reset.

August 9, 1993
Implemented new method to interpolate between levels.

August 10, 1993
Metadata restored to end of archive tape.

August 17, 1993
MSU quarterly calibration for NOAA-11 and NOAA-12.

August 19, 1993
NOAA-11 data from 18:37 to 20:00 not processed (large HIRS data gaps)

August 23, 1993
Coefficient update for NOAA-11 and NOAA-12

August 23, 1993
NOAA-12 data from 14:00 to 14:48 missing. Data not received.

August 30, 1993
Coefficient update for NOAA-11 and NOAA-12

August 30, 1993
NOAA-11 data from 9:44 to 11:30 not processed.

August 31, 1993
NOAA-11 data from 21:08 to 22:57 not processed.

September 7, 1993
Coefficient updates for NOAA-11 and NOAA-12

September 13, 1993
Coefficient updates for NOAA-11 and NOAA-12

September 14, 1993
Implemented water vapor upgrade ($PTRET) at 10 am.

September 20, 1993



                                        D-29       NOAA POD Guide - Jan. 2002 Revision29
Coefficient update for NOAA-11 and NOAA-12

September 27, 1993
New version of PHYSEL in radiosonde match

September 28, 1993
New PHYSEL recompiled, was flagging new matchups as redundant.

September 29, 1993
Coefficient updates for NOAA-11 and NOAA-12.

October 4, 1993
Coefficient updates for NOAA-11 and NOAA-12.

October 12, 1993
Coefficient updates for NOAA-11 and NOAA-12.

October 12, 1993
NOAA-11 space view calibration for HIRS Channels 13,14, and 16 were updated.

October 18, 1993
Coefficient updates for NOAA-11 and NOAA-12.

October 25, 1993
Coefficient updates for NOAA-11 and NOAA-12.

November 1, 1993
Some NOAA-12 orbits were not processed due to earth location problems.

November 1, 1993
Coefficient updates for NOAA-11 and NOAA-12.

November 2, 1993
Three NOAA-11 orbits were not processed due to problems with the stability departure
software.

November 4, 1993
Two NOAA-12 orbits (6:40 to 9:16 Z) were not received due to tracking problems at the
CDAs. Several NOAA-11 orbits were short or fragmented.

November 14, 1993
Coefficient updates for NOAA-11 and NOAA-12.

November 22, 1993
Coefficient updates for NOAA-11 and NOAA-12.




                                       D-30        NOAA POD Guide - Jan. 2002 Revision30
November 23, 1993
Implemented new $PTRET to include 50% Water retrieval constraint.

November 30, 1993
Coefficient updates for NOAA-11 and NOAA-12.

December 1, 1993
NOAA-12 data from 19:45 to 21:20 not received for processing.

December 6, 1993
Coefficient updates for NOAA-11 and NOAA-12.

December 13, 1993
Coefficient update for NOAA-11 and NOAA-12

December 18, 1993
NOAA-12 data from 5:27 to 6:52 not processed (large HIRS data gaps).

December 20, 1993
Coefficient updates for NOAA-11 and NOAA-12.

December 22, 1993
NOAA-11 data from 23:26 to 1:07 not processed (poor quality).

December 27, 1993
Coefficient updates for NOAA-11 and NOAA-12.

January 1, 1994
NOAA-11 data from 19:23 to 21:02 not processed (large HIRS data gaps).

January 4, 1994
NOAA-12 data from 21:47 to 22:39 not received for processing.

January 9, 1994
NOAA-11 data from 6:21 to 8:09 not processed. NOAA-11 data from 8:17 to 9:48 not
processed.

January 10, 1994
Coefficient updates for NOAA-11 and NOAA-12.

January 18, 1994
NOAA-12 data from 00:15 to 2:00 not processed due to missing earth location.

January 19, 1994
HIRS channel 12 added to clear/N* channels for the calculation of the retrieval operator.




                                        D-31          NOAA POD Guide - Jan. 2002 Revision31
January 21, 1994
NMC/CAC reported bad temperature data at 1 and 2 mb for limited regions in both
hemispheres.

January 24, 1994
HIRS channel 15 space view filtering limits were adjusted.

January 24, 1994
Coefficient updates for NOAA-11 and NOAA-12.

January 26, 1994
Re-ran coefficient update to exclude channel 12 for NOAA-11 clears.

January 28, 1994
NOAA-11 data from 19:26 to 20:30 not processed (HIRS data gaps).

January 31, 1994
Coefficient updates for NOAA-11 and NOAA-12.

February 4, 1994
Data from 04:00 to 12:38Z were not archived due to processing problems.

February 6, 1994
NOAA-11 data from 20:24 to 22:01 were not received.

February 7, 1994
Coefficient update for NOAA-11 and NOAA-12.

February 12, 1994
NOAA-11 data from 19:50 to 20:49 were not received.

February 14, 1994
Coefficient updatess for NOAA-11 and NOAA-12.

February 14, 1994
NOAA-12 data from 21:08 to 22:31 were not received.

February 15, 1994
Data from February 13, 1994 not on archive due to processing problems.

February 15, 1994
NOAA-12 data from 9:02 to 10:49 were not received.

February 19, 1994
NOAA-11 data from 6:13 to 7:59 were not processed due to MSU and SSU channel
failures.



                                        D-32         NOAA POD Guide - Jan. 2002 Revision32
February 20, 1994
NOAA-11 data from 17:49 to 19:15 were not received.

February 20, 1994
NOAA-12 data from 6:09 to 7:00 were not received.

February 22, 1994
Coefficient updates for NOAA-11 and NOAA-12.

February 24, 1994
NOAA-11 data from 6:51 to 8:35 were not processed due to poor quality data.

February 24, 1994
NOAA-12 data from 2:09 to 5:27 were not processed due to antenna problems. NOAA-
12 data from 9:08 to 12:33 were not processed because of poor quality data.

February 25, 1994
NOAA-11 data from 8:27 to 10:07 were not received.

February 27, 1994
NOAA-12 data from 9:44 to 11:31 were not processed due to poor quality data.

February 28, 1994
NOAA-11 data from 2:22 to 4:10 were not processed due to MSU channel failure.

March 2, 1994
NOAA-12 data from 23:48 to 1:36 were not processed due to poor quality data.

March 3, 1994
NOAA-12 data from 13:25 to 15:13 and from 18:22 to 19:59 were not received.

March 7, 1994
Coefficient updates for NOAA-11 and NOAA-12.

March 11, 1994
NOAA-12 data from 23:54 to 1:38 were not processed due to no earth location.

March 13, 1994
NOAA-11 data from 6:43 to 8:29 were not received.

March 14, 1994
Coefficient updates for NOAA-11 and NOAA-12.

March 15, 1994
NOAA-11 data from 6:18 to 8:03 were not received.



                                       D-33          NOAA POD Guide - Jan. 2002 Revision33
March 15, 1994
NOAA-12 data from 10:47 to 14:05 were not received.

March 21, 1994
Coefficient updates for NOAA-11 and NOAA-12.

March 21, 1994
NOAA-11 data from 00:15 to 1:22 were not received.

March 22, 1994
NOAA-12 data from 6:10 to 11:33 were not received.

March 23, 1994
NOAA-11 data from 2:44 to 4:51 were not received.

March 25 - 28, 1994
Some NOAA-11 data and NOAA-12 data were noisy and precluded calibration.

March 28, 1994
Coefficient updates for NOAA-11 and NOAA-12.

March 28, 1994
NOAA-11 channel 13 warm body calibration limits were adjusted.

March 29, 1994
NOAA-11 channel 8 space view calibration limits were adjusted.

March 31, 1994
NOAA-11 data from 3:20 to 4:30 were fragmented and not completely received.

April 4, 1994
Coefficient updates for NOAA-11 and NOAA-12.

April 5, 1994
NOAA-12 data from 4:26 to 6:05 and from 7:56 to 9:43 were not received.

April 6, 1994
NOAA-12 data from 22:33 to 00:07 were not received.

April 7, 1994
NOAA-12 data from 9:02 to 10:47 were not received.

April 14, 1994
NOAA-12 data from 15:08 to 16:30 were not processed due to MSU channel failure.




                                      D-34           NOAA POD Guide - Jan. 2002 Revision34
April 16, 1994
NOAA-11 data from 5:16 to 6:25 were not received.

April 18, 1994
NOAA-12 MSU channels 2 and 4 calibration intercept lower limits were updated.

April 20, 1994
NOAA-12 data from 16:08 to 17:55 were not received.

April 21, 1994
NOAA-12 data from 14:08 to 15:54 were not received.

April 22, 1994
NOAA-11 data from 10:26 to 12:15 were not received.

April 23, 1994
NOAA-12 data from 1:15 to 4:48 were not processed due to problems in processing.

April 26, 1994
NOAA-11 data from 9:37 to 10:07 were not received.

April 28, 1994
Implemented a new retrieval processor to use HIRS channels 10,11 and 12 (water vapor
channels) in the retrieval step.

May 2, 1994
Coefficient updates for NOAA-11 and NOAA-12.

May 2, 1994
NOAA-12 data from 6:25 to 8:11 were not received.

May 9, 1994
Coefficient update for NOAA-11 and NOAA-12.

May 9, 1994
NOAA-11 data from 22:14 to 00:03 were not received.

May 10, 1994
NOAA-11 HIRS channel 13 warm black body calibration limits adjusted.

May 12, 1994
NOAA-11 data from 4:21 to 6:08 and from 7:29 to 9:41 not received.

May 16, 1994
NOAA-12 HIRS channel 14 space view calibration limits adjusted. NOAA-12 HIRS
channel 8, 14, and 17 warm black body calibration limits adjusted.



                                      D-35           NOAA POD Guide - Jan. 2002 Revision35
May 16, 1994
Coefficient update for NOAA-11 and NOAA-12.

May 23, 1994
Coefficient update for NOAA-11 and NOAA-12.

May 25, 1994
NOAA-11 data from 23:49 to 1:37 not processed due to poor quality data.

May 31, 1994
Coefficient update for NOAA-11 and NOAA-12.

May 31, 1994
NOAA-12 data from 14:53 to 16:15 were not received.

June 6, 1994
Coefficient update for NOAA-11 and NOAA-12

June 12, 1994
NOAA-12 data from 1:35 to 3:14 and from 4:57 to 6:39 were not received.

June 13, 1994
Coefficient update for NOAA-11 and NOAA-12.

June 20, 1994
Coefficient update for NOAA-11 and NOAA-12.

June 20, 1994
NOAA-11 data from 3:45 to 4:53 and from 10:37 to 11:21 were not received.

June 24, 1994
NOAA-12 data from 21:23 to 22:58 were not received.

June 26, 1994
NOAA-12 data from 10:16 to 11:59 were not received.

June 27, 1994
Coefficient update for NOAA-11 and NOAA-12.

June 27, 1994
Two NOAA-12 orbits were not processed.

July 5, 1994
Coefficient update for NOAA-11 and NOAA-12.




                                       D-36        NOAA POD Guide - Jan. 2002 Revision36
July 5, 1994
NOAA-12 data from 5:00 to 6:41 were not received.

July 6, 1994
NOAA-11 data from 15:24 to 16:54 were not received.

July 11, 1994
Coefficient update for NOAA-11 and NOAA-12.

July 12, 1994
NOAA-12 data from 19:41 to 21:09 were not received.

July 18, 1994
Coefficient update for NOAA-11 and NOAA-12.

July 19, 1994
NOAA-12 data from 6:40 to 8:28 and from 9:37 to 10:15 were not received.

July 22, 1994
NOAA-12 data from 15:56 to 17:32 were not received.

July 25, 1994
Coefficient update for NOAA-11 and NOAA-12.

July 27, 1994
NOAA-12 data from 21:10 to 22:48 were not processed due to earth location errors.

August 1, 1994
Coefficient update for NOAA-11 and NOAA-12.


August 8, 1994
Coefficient update for NOAA-11 and NOAA-12.

August 15, 1994
Coefficient update for NOAA-11 and NOAA-12.

August 15, 1994
NOAA-11 data from 5:24 to 7:44 were not received due to antenna problems at Wallops
Island.

August 22, 1994
Coefficient update for NOAA-11 and NOAA-12.

August 29, 1994
Coefficient update for NOAA-11 and NOAA-12.



                                       D-37         NOAA POD Guide - Jan. 2002 Revision37
September 3-6, 1994
Many NOAA-11 orbits were not processed due to calibration problems.

September 6, 1994
NOAA-11 HIRS channel 13, 16, and 17 cold black body calibrations were adjusted.

September 7, 1994
NOAA-11 HIRS channel 13 space view calibration were adjusted.

September 8, 1994
NOAA-11 HIRS housekeeping calibration parameters were adjusted.

September 12, 1994
NOAA-11 HIRS channel 14 space view calibration were adjusted.

October 3, 1994
Coefficient updates for NOAA-11 and NOAA-12.

October 3, 1994
NOAA-11 data from 15:20 to 17:00 were not received.

October 9, 1994
NOAA-11 data from 5:54 to 7:24 were not processed due to MSU channel 3 failures.

October 9, 1994
NOAA-11 data from 20:45 to 22:31 were not processed due to gross earth location errors.

October 10, 1994
NOAA-11 data from 5:38 to 8:56 and from 12:25 to 13:51 were not processed due to
MSU channel failures.

October 11, 1994
NOAA-11 data from 7:01 to 12:10 were not processed due to MSU channel failures.

October 11, 1994
NOAA-11 MSU PRT temperature calibration was adjusted.

October 11, 1994
Coefficient update for NOAA-11 and NOAA-12.

October 17, 1994
Coefficient update for NOAA-11 and NOAA-12.

October 24, 1994
Coefficient update for NOAA-11 and NOAA-12.



                                       D-38         NOAA POD Guide - Jan. 2002 Revision38
October 24, 1994
NOAA-11 data from 7:36 to 9:22 were not processed due to large HIRS data gaps.

October 26, 1994
NOAA-12 data from 5:57 to 7:43 were not received.

October 28, 1994
NOAA-12 data from 20:57 to 22:20 were not received.

October 30, 1994
NOAA-12 data from 16:54 to 18:10 were not received.

October 31, 1994
Coefficient update for NOAA-11 and NOAA-12.

November 7, 1994
Coefficient update for NOAA-11 and NOAA-12.

November 14, 1994
Coefficient update for NOAA-11 and NOAA-12.

November 21, 1994
Coefficient update for NOAA-11 and NOAA-12.

November 29, 1994
Coefficient update for NOAA-11 and NOAA-12.

December 7, 1994
NOAA-11 data from 23:52 to 1:32 not processed due to poor quality data.

December 8, 1994
NOAA-11 data from 6:43 to 8:23 not processed due to poor quality data.

December 10, 1994
NOAA-11 data from 16:37 to 18:09 were not received.

December 15, 1994
NOAA-11 data from 19:03 to 3:19 were not received.

December 15, 1994
NOAA-12 data from 21:57 to 0:58 were not received.

December 18, 1994
NOAA-12 data from 22:18 to 23:52 were not received.




                                       D-39          NOAA POD Guide - Jan. 2002 Revision39
January 23, 1995
Implemented upgrade to improve selection of first guess for cloudy retrievals, added
MSU channel 2 to retrieval process in polar regions without high terrain.

April 10, 1995
Processing from NOAA-11 discontinued due to bring up of NOAA-14 and NWS need for
NOAA-9 SBUV data. Mapped SSU data for NOAA-12 supplied by NOAA-14 non-
operational system operating without a MSU.

May 1, 1995
NOAA-12 data missing from 23:49 to 01:34.

May 1, 1995
NOAA-12 data missing from 17:04 to 18:42 and from 22:04 to 01:06.

May 2, 1995
NOAA-12 data missing from 11:46 to 13:24. Replaced the SSU mapped fields in
NOAA-12 with NOAA-14 data with the MSU. Believed problem with the generation of
SSU data from NOAA-14 system without the MSU.

May 10, 1995
NOAA-12 data missing from 23:54 to 1:40.

June 2, 1995
NOAA-12 data missing from 00:17 to 5:26.

June 7, 1995
NOAA-14 (with the MSU) became operational.

June 18, 1995
OAA-12 data missing from 9:38 to 11:31.

June 19, 1995
Implemented new asymmetrical scan coefficients for MSU on NOAA-12.

July 6, 1995
NOAA-12 data missing from 15:04 to 16:30.

July 19, 1995
NOAA-12 data missing from 10:06 to 11:50 and from 18:28 to 20:05.
.
July 30, 1995
NOAA-12 data missing from 2:24 to 4:03.

July 31, 1995
NOAA-14 data missing from 10:08 to 13:26.



                                        D-40         NOAA POD Guide - Jan. 2002 Revision40
August 3, 1995
NOAA-14 data missing from 19:25 to 21:09.

August 10, 1995
NOAA-12 data missing from 6:56 to 8:43.

August 18, 1995
NOAA-14 data missing from 5:14 to 6:54 and from 22:05 to 23:43.

August 30, 1995
NOAA-12 data missing from 1:02 to 1:53.

September 9, 1995
NOAA-14 data missing from 23:10 to 00:51.

September 10, 1995
NOAA-12 data missing from 16:17 to 17:34.


September 12, 1995
NOAA-12 data missing from 4:49 to 6:28.

September 19, 1995
NOAA-14 data missing from 7:54 to 9:40.

September 21, 1995
NOAA-14 data missing from 12:31 to 14:09.

September 22, 1995
NOAA-12 data missing from 18:15 to 19:50.

September 23, 1995
NOAA-14 data missing from 12:09 to 13:48.

September 25, 1995
NOAA-14 data missing from 10:06 to 11:48.

September 28, 1995
NOAA-12 data missing from 00:26 to 2:17.

September 29, 1995
NOAA-14 data missing from 19:23 to 22:52.

October 1, 1995
NOAA-14 data missing from 14:04 to 15:43.



                                      D-41        NOAA POD Guide - Jan. 2002 Revision41
October 6, 1995
NOAA-14 data missing from 23:19 to 1:02.

October 7, 1995
NOAA-14 data missing from 21:27 to 23:04.

October 8, 1995
NOAA-14 data missing from 9:38 to 11:03 and from 21:16 to 00:40.

October 13, 1995
NOAA-14 data missing from 21:52 to 23:32.

October 15, 1995
NOAA-12 data missing from 23:23 to 1:04.

October 16, 1995
NOAA-14 data missing from 22:20 to 00:53.

October 18, 1995
NOAA-14 data missing from 22:53 to 00:32.

October 22, 1995
NOAA-14 data missing from 20:12 to 21:52.

October 24, 1995
NOAA-14 data missing from 9:06 to 13:11, from 14:57 to 16:45 and from 23:26 to 1:06.

October 25, 1995
NOAA-12 data missing from 14:57 to 16:45 and from 22:48 to 23:13.

October 30, 1995
NOAA-12 data missing from 16:07 to 17:47.

November 2, 1995
NOAA-12 data missing from 18:23 to 20:14.

November 5, 1995
NOAA-12 data missing from 12:47 to 14:24.

November 17, 1995
NOAA-12 data missing from 22:00 to 23:00.

November 27, 1995
NOAA-12 data missing from 17:38 to 19:25.




                                      D-42         NOAA POD Guide - Jan. 2002 Revision42
January 1, 1996
NOAA-12 data missing from 23:22 to 00:02. NOAA-14 data missing from 23:59 to 2:59

January 4, 1996
NOAA-12 data missing from 5:08 to 6:54

January 7, 1996
NOAA-14 data missing from 11:28 to 14:47

January 19, 1996
NOAA-14 data missing from 14:20 to 15:56


January 24, 1996
NOAA-12 data missing from 2:51 to 4:29 and from 13:19 to 16:56. NOAA-14 data
missing from 16:46 to 19:52. Missing orbits due to a file problem in the orbital
processing.

January 25, 1996
NOAA-12 data missing from 5:51 to 7:39. Daily surface update job moved from the
NWS HDS computer to the NESDIS CEMSCS computer.

January 26, 1996
NOAA-12 data missing from 9:08 to 10:53. NOAA-14 data missing from 4:35 to 6:22.

February 1, 1996
Surface update job on the CEMSCS was not getting the sea data updated since the
January 25 implementation. Problem corrected and sea data is now being updated.
NOAA-12 data missing from 17:24 to 18:38.

February 6, 1996
NOAA-14 data missing from 19:12 to 20:58

February 11, 1996
NOAA-14 data missing from 11:51 to 13:28

February 17, 1996
NOAA-12 data missing from 14:45 to 16:09

February 21, 1996
NOAA-12 data missing from 16:46 to 18:04. NOAA-14 data missing from 10:02 to
11:46.

February 25, 1996
NOAA-14 data missing from 21:24 to 22:26.




                                      D-43         NOAA POD Guide - Jan. 2002 Revision43
March 1, 1996
NOAA-12 data missing from 8:29 to 9:42.

March 2, 1996
NOAA-12 data missing from 19:27 to 21:03.

March 3, 1996
NOAA-12 data missing from 15:49 to 16:53 and from 17:55 to 19:01.

March 11, 1996
NOAA-12 data missing from 12:55 to 14:41 and from 16:11 to 17:49. NOAA-14 data
missing from 14:59 to 16:38 due to no synchronized MSU major frame being found.

March 12, 1996
NOAA-14 data missing from 21:36 to 2:48.

March 13, 1996
NOAA-14 data missing from 21:24 to 00:47 and from 1:07 to 2:38.

March 14, 1996
NOAA-14 data missing from 21:12 to 2:23. Problems with missing NOAA-14 data for
the last 3 days are due to forecast data not being updated on a TOVS file.

March 17, 1996
NOAA-12 data missing from 3:36 to 5:14.

March 19, 1996
NOAA-14 data missing from 13:33 to 15:13 and from 20:14 to 21:45.

March 20, 1996
NOAA-14 data missing from 23:35 to 1:14.

March 23, 1996
NOAA-12 data missing from 18:15 to 19:01.

March 26, 1996
NOAA-14 data missing from 5:35 to 7:13.

March 28, 1996
NOAA-14 data missing from 15:19 to 16:40.

April 12, 1996
NOAA-14 data missing from 2:37 to 3:59.

April 25, 1996
NOAA-12 data missing from 6:09 to 9:45. NOAA-14 data missing from 10:11 to 11:50.



                                      D-44        NOAA POD Guide - Jan. 2002 Revision44
April 30, 1996
NOAA-14 data missing from 1:05 to 7:53.

May 6, 1996
NOAA-14 data missing from 16:35 to 17:55.

May 14, 1996
NOAA-14 data missing from 11:47 to 13:26.

June 14, 1996
NOAA-14 data missing from 21:20 to 22:58 and from 7:54 to 9:38.

June 16, 1996
NOAA-14 data missing from 2:12 to 3:57.

June 21, 199
NOAA-14 data missing from 23:27 to 1:08.

June 22, 1996
NOAA-14 data missing from 13:06 to 14:45.

July 1, 1996
NOAA-12 data missing from 17:08 to 18:44.

July 4, 1996
NOAA-12 data missing from 0:29 to 2:17.
 NOAA-14 data missing from 14:17 to 15:53.

July 5, 1996
NOAA-12 data missing from 5:19 to 7:05.

July 12, 1996
NOAA-14 data missing from 2:31 to 4:22.

July 18, 1996
NOAA-12 data missing from 2:13 to 3:50.

July 20, 1996
NOAA-12 data missing from 3:09 to 4:50.

July 21, 1996
NOAA-12 data missing from 4:28 to 6:09.

July 22, 1996
NOAA-12 data missing from 21:08 to 22:49.



                                      D-45        NOAA POD Guide - Jan. 2002 Revision45
July 23, 1996
NOAA-12 data missing from 9:04 to 10:51.

July 24, 1996
NOAA-14 data missing from 18:57 to 22:28.

July 26, 1996
NOAA-12 data missing from 13:06 to 16:17. NOAA-14 data missing from 8:40 to
10:12.

July 29, 1996
NOAA-12 data missing from 20:21 to 21:39.

July 30, 1996
NOAA-12 data missing from 23:20 to 1:08.

August 7, 1996
NOAA-14 data missing from 4:00 to 4:52.

August 10, 1996
NOAA-14 data missing from 22:46 to 0:25.

August 12, 1996
NOAA-14 data missing from 17:01 to 18:38.

August 13, 1996
NOAA-12 data missing from 20:11 to 23:13 and from 10:07 to 11:31. NOAA-14 data
missing from 23:54 to 1:44.

August 16, 1996
NOAA-14 data missing from 1:04 to 2:33 and from 14:52 to 16:30.

August 23, 1996
NOAA-12 data missing from 7:39 to 8:49. NOAA-14 data missing from 10:14 to 11:50.

September 12, 1996
NOAA-12 data missing from 5:11 to 8:45 and from 20:34 to 21:54. NOAA-14 data
missing from 18:43 to 19:44.

September 14, 1996
NOAA-12 data missing from 21:38 to 23:13.

September 22, 1996
NOAA-12 data missing from 20:16 to 21:37.




                                      D-46        NOAA POD Guide - Jan. 2002 Revision46
September 24, 1996
NOAA-12 data missing from 16:12 to 17:47.

September 27, 1996
NOAA-14 data missing from 5:47 to 7:36.
October 2, 1996

NOAA-14 data missing from 16:23 to 17:44.

October 4, 1996
NOAA-12 data missing from 15:53 to 17:30.

October 9, 1996
NOAA-12 data missing from 10:48 to 12:25.

October 12, 1996
NOAA-12 data missing from 13:02 to 14:48.

October 19, 1996
NOAA-12 data missing from 5:03 to 6:52.
NOAA-14 data missing from 2:38 to 4:58.

October 21, 1996
NOAA-14 data missing from 6:16 to 7:53.

October 29, 1996
NOAA-12 data missing from 3:10 to 4:40 and from 20:16 to 21:31.

October 30, 1996
NOAA-12 data missing from 4:21 to 6:03, 7:54 to 9:10 and from 11:29 to 13:05.

November 7, 1996
NOAA-12 data missing from 10:15 to 11:53.

November 15, 1996
NOAA-12 data missing from 7:02 to 8:49, 10:40 to 12:14 and from 20:57 to 22:18.

November 16, 1996
NOAA-14 data missing from 1:08 to 3:03 and from 6:36 to 8:15.

November 20, 1996
NOAA-14 data missing from 10:50 to 12:26 and from 19:05 to 20:46.

November 28, 1996
NOAA-12 data missing from 00:17 to 2:02




                                      D-47         NOAA POD Guide - Jan. 2002 Revision47
December 7, 1996
NOAA-12 data missing from 21:25 to 22:39.


December 23, 1996
NOAA-12 data missing from 18:24 to 20:03.

December 28, 1996
NOAA-14 data missing from 23:10 to 0:08.

October 22, 1997
RTOVS NOAA-14 operational processing and archive began.

October 24, 1997
Data missing for NOAA-14 from 0425 to 0606UTC.

October 28, 1997
SPGDVR and BLDLIB modules were updated.

October 28, 1997
Data missing for NOAA-14 from 2347 to 0129 UTC on October 29.

October 29, 1997
Updated NOAA-14 coefficients.

October 29, 1997
Coefficient database (CDB) archive began

November 2, 1997
Radiosonde match did not run today, changes in JCL=s for other days didn=t get into the
Sunday JCL.

November 3, 1997
Updated NOAA-14 coefficients.

November 10, 1997
Radiosonde match did not run again. Correction to Sunday JCL had error in the typing.

November 12, 1997
Updated NOAA-14 coefficients.

November 18, 1997
Updated NOAA-14 coefficients.

November 19, 1997
RTOVS NOAA-11 operational processing and archive began.



                                       D-48         NOAA POD Guide - Jan. 2002 Revision48
November 19, 1997
Data missing for NOAA-14 from 0812 to 1445UTC.

November 20, 1997
Data missing for NOAA-14 from 1925 to 0038 UTC on November 21.

November 23, 1997
Reported NOAA-11 processing is using NOAA-14 transmittance coefficients.

November 25, 1997
Data missing for NOAA-11 from 1734 to 1838 UTC.

November 28, 1997
Updated NOAA-14 and NOAA-11 coefficients.

November 29, 1997
Data missing for NOAA-14 from 2007 to 2359 UTC.

November 30, 1997
Data missing for NOAA-14 from 0000 to 2103 UTC.

December 1, 1997
NOAA-14 data missing from 0220 to 0433 UTC.

December 2, 1997
NOAA-14 data missing from 2041 to 1358 UTC on December 3.

December 8, 1997
NOAA-14 data missing from 0244 to 0427 and from 1303 to 1436 UTC.

December 9, 1997
NOAA-14 data missing from 0935 to 1104 UTC.

December 11, 1997
NOAA-14 data missing from 0903 to 1403 UTC.

December 16, 1997
Orbital processing modified to look for most recent forecast file instead of only file in
certain time frame. Some orbital processing was lost when current forecast file was
unavailable.

December 19, 1997
NOAA-14 data missing from 0223 to 0405 UTC.

December 25, 1997



                                          D-49         NOAA POD Guide - Jan. 2002 Revision49
NOAA-11 data missing from 0007 to 0619 UTC.

December 28, 1997
NOAA-14 data missing from 0035 to 0357 and from 2059 to 2235 UTC.

December 29, 1997
NOAA-14 data missing from 0544 to 0910 UTC.

January 5, 1998
Updated NOAA-11 coefficients.

January 6, 1998
Updated NOAA-14 coefficients.

January 11, 1998
NOAA-14 data missing from 0752 to 0825 UTC.

January 12, 1998
Updated NOAA-14 and NOAA-11 coefficients.

January 20, 1998
Updated NOAA-14 and NOAA-11 coefficients.

January 26, 1998
Updated NOAA-14 and NOAA-11 coefficients.

January 29, 1998
The filter flag was incorrectly packed in the file.
 Logic was added to convert the HIRS scan number to box and minibox numbers.

February 1, 1998
NOAA-11 data missing from 0845 to 1357 UTC.
NOAA-14 data missing from 0000 to 2258 UTC.

February 2, 1998
Updated NOAA-14 and NOAA-11 coefficients.

February 2, 1998
NOAA-11 data missing from 1924 to 2005 UTC.

February 04, 1998
NOAA-14 data missing from 0910 to 1039 UTC.

February 9, 1998
Updated NOAA-14 and NOAA-11 coefficients.




                                      D-50        NOAA POD Guide - Jan. 2002 Revision50
February 10, 1998
NOAA-14 data missing from 2116 to 0040 UTC on February 11.

February 12, 1998
NOAA-11 data missing from 0002 to 0150 UTC.

February 16, 1998
NOAA-11 data missing from 1135 to 1242 UTC.

February 17, 1998
Updated NOAA-14 and NOAA-11 coefficients.

February 17, 1998
NOAA-11 data missing from 0627 to 1349 UTC.

February 19, 1998
NOAA-11 data missing from 1339 to 1831 UTC.

February 23, 1998
Updated NOAA-14 and NOAA-11 coefficients.

February 24, 1998
NOAA-11 data missing from 1103 to 1232UTC.
NOAA-14 data missing from 2206 to 2341 UTC.

February 25, 1998
Corrected inconsistent handling of time less than 0100 UTC. The product generation
software would assign the hour of 24 which was unacceptable for the archive software.
This prevented the archive of data less than 0100 UTC.

February 25, 1998
NOAA-11 data missing from 0035 to 0136 UTC.

February 27, 1998
NOAA-14 data missing from 1316 to 1450 UTC.

March 2, 1998
Updated NOAA-14 and NOAA-11 coefficients.

March 5, 1998
Added six thresholds to cloud detection. Improved use of land and sea eigenvectors.
Enhanced SSU quality checks. Require first guess records to have first significant level
greater than or equal to 950mb. Improved product over sea ice by allowing flexible field
of view selection and improved application of window channel tests.

March 7, 1998



                                        D-51         NOAA POD Guide - Jan. 2002 Revision51
NOAA-11 data missing from 0502 to 0626; 1105 to 1206, and from 1735 to 1835 UTC.

March 9, 1998
Updated NOAA-14 and NOAA-11 coefficients.

March 15, 1998
NOAA-11 data missing from 0018 to 0206 UTC.
NOAA-14 data missing from 0216 to 0318 UTC.

March 16, 1998
Updated NOAA-14 and NOAA-11 coefficients.

March 18, 1998
NOAA-11 data missing from 0041 to 0231 UTC.

March 20, 1998
NOAA-14 data missing from 1912 to 2053 UTC.

March 23, 1998
Updated NOAA-14 and NOAA-11 coefficients.

March 28, 1998
NOAA-14 data missing from 2111 to 0035 UTC on March 29.

March 30, 1998
Updated NOAA-14 and NOAA-11 coefficients.

April 1, 1998
NOAA-11 data missing from 1906 to 2004 UTC

April 3, 1998
NOAA-11 data missing from 0829 to 0935 UTC.

April 11, 1998
NOAA-11 data missing from 0557 to 0747 UTC and from 1308 to 1456 UTC.
NOAA-14 data missing from 0142 to 0303 UTC.

April 11, 1998
NOAA-11 data missing from 2331 on April 11 to 0119 UTC on April 12.

April 12, 1998
Improved coefficient update system: (1) improved the cloud products by using water
vapor attenuated HIRS channel 8; (2) improved computation of the sum of squares.

April 13, 1998
NOAA-14 data missing from 1808 to 0102 UTC on April 14.



                                       D-52         NOAA POD Guide - Jan. 2002 Revision52
April 19, 1998
NOAA-14 data missing from 0250 to 0337 UTC.

April 21, 1998
NOAA-11 data missing from 2334 on April 21 to 0109 UTC on April 22.

April 24, 1998
NOAA-11 data missing from 0022 to 0211 UTC.

April 27, 1998
NOAA-11 data missing from 1742 to 1844 UTC.

April 28, 1998
NOAA-11 data missing from 0546 to 0924 UTC.
NOAA-14 data missing from 1926 to 2019 UTC.

May 6, 1998
NOAA-14 data missing from 2039 to 2221 UTC.

May 7, 1998
NOAA-14 data missing from 1307 to 1352 UTC.

May 8 - 10, 1998
A line problem with the Fairbanks Command Data Acquisition Station prevented the
receipt of NOAA-11 orbits read out at that site. No recovery was possible.

May 8, 1998
NOAA-11 data missing from1413 to 1905 UTC. NOAA-14 data missing from 0141 to
0328 UTC.

May 9, 1998
NOAA-11 data missing from 0138 to 0646 and from 1401 to 1852 UTC.

May 10, 1998
NOAA-11 data missing from 0125 to 0632 UTC.

May 13, 1998
Improved total ozone computation by using the weighted average of 0.85 limb corrected
HIRS channel 8 and 0.15 limb corrected HIRS channel 10 to compute the stratospheric
background temperature.

May 17, 1998
NOAA-11 data missing from1745 to 2123 UTC.

May 18, 1998



                                       D-53        NOAA POD Guide - Jan. 2002 Revision53
NOAA-11 data missing from 0344 to 0723; 1112 to 1450 and from 1840 to 2219 UTC.

May 19, 1998
NOAA-11 data missing from 0332 to 0726 and from 1116 to 1547 UTC.

May 19-20, 1998
NOAA-11 data missing from 2322 on May 19 to 0005 UTC on May 20.

May 20, 1998
NOAA-11 data missing from 0740 to 1534 UTC.

May 29, 1998
NOAA-11 data missing from 2040 to 2141 UTC.

June 1, 1998
Updated NOAA-14 and NOAA-11 coefficients.

June 2, 1998
Radiosonde match-up selection was changed to base selection on timeliness as well a
geographic representation, as geographic representation was weighted too heavily.

June 2, 1998
NOAA-11 data missing from 1041 to 1328 UTC.

June 8, 1998
Updated NOAA-14 and NOAA-11 coefficients.

June 15, 1998
Updated NOAA-14 and NOAA-11 coefficients.

June 17, 1998
Corrected problem with SSU products over the poles.

June 17, 1998
NOAA-11 data missing from 1052 to 1241 UTC.

June 21, 1998
NOAA-11 data missing from 0448 to 0637 UTC.

June 22, 1998
Disabled SSU channel 3 from NOAA-11 and NOAA-14 processing (NOAA-11 SSU is
mapped to NOAA-14 data). Poor quality data at 2mb was reported prior to disabling
SSU channel 3.

June 22, 1998
Updated NOAA-14 and NOAA-11 coefficients.



                                       D-54           NOAA POD Guide - Jan. 2002 Revision54
June 22-28, 1998
No archive available for NOAA-11 data.

June 23, 1998
NOAA-14 data missing from 1526 to 1659 UTC.

June 24, 1998
Plumbing problems caused problems in the computer room and prevented processing of
orbital data from midnight until 0826 EST, some data may be missing from the archive as
a result.

June 25, 1998
Improved filtering of SSU data to filter out data that fails the gross limits check. SSU
channel 3 enabled since bad data will now be filtered.

June 25, 1998
Radiation correction software was updated with latest version from NCEP. Earlier
version was not correcting all of the radiosondes it should have been correcting.

June 25, 1998
NAA-11 data missing from 1053 to 1411 and from 1608 to 1755 UTC.

June 26, 1998
The SSU map from the parallel system was copied in to the operations. The operational
map was found to contain bad data whereas the parallel map was clean.

June 26, 1998
NOAA-11 data missing from 0142 to 0330; 0526 to 0650; 0847 to 1034; 1231 to 1358
and from 1749 to 1859 UTC. NOAA-14 data missing from 0439 to 0621 UTC.

June 29, 1998
NOAA-11 data missing from 1509 to 1657 UTC.

June 30, 1998
Updated NOAA-14 and NOAA-11 coefficients.

June 30, 1998
Updated NOAA-11 limb correction coefficients for MSU at 2000 UTC. Small impact on
channels 1, 2, and 3 of about 0.5K. Channels 2 and 3 appear to have slightly less scan
angle pattern in the tropics. Channel 4 has a bimodal impact and a definite improvement.

July 1, 1998
NOAA-11 data missing from 0605 to 0729 UTC

July 1, 1998



                                         D-55          NOAA POD Guide - Jan. 2002 Revision55
NOAA-11 data missing from 2326 on July 1 to 0115 UTC on July 2.

July 2, 1998
The problem with the SSU data was isolated to the smoothing software. At 1600 UTC,
the TOVS smoother was installed (which was tested and determined to be working
properly) while the RTOVS version was corrected.

July 3, 1998
NOAA-11 data missing from 1106 to 1245 UTC.

July 5, 1998
NOAA-14 data missing from 0443 to 0623 UTC.

July 7, 1998
Updated NOAA-14 and NOAA-11 coefficients.

July 12, 1998
NOAA-14 data missing from 0504 to 0646 UTC.

July 13, 1998
Updated NOAA-14 and NOAA-11 coefficients.

July 13, 1998
Turned on SSU channel 3 in NOAA-11 and NOAA-14 CDBs.

July 13, 1998
NOAA-14 data missing from 0453 to 0634 UTC.

July 14, 1998
Updated NOAA-14 limb coefficients for MSU and HIRS at 1400 UTC. The impact for
MSU is very similar to that for the NOAA-11 MSU. For the HIRS, channels 4 through
13 showed a reduction on the limb range from 0.5K for channel12 to 1.3K for channel
10. Channel 13 was the only HIRS channel with a bimodal impact (vs. latitude). Other
channels had an impact of less than 0.25K.

July 14, 1998
NOAA-11 data missing from 1726 to 1914 UTC.

July 16, 1998
Development SSU Map was copied into operations.

July 17, 1998
NOAA-14 data missing from 2251 to 0013 UTC on July 18.

July 18, 1998
NOAA-14 data missing from 0540 to 0721 and from 2238 to 2359 UTC.



                                      D-56         NOAA POD Guide - Jan. 2002 Revision56
July 19, 1998
NOAA-14 data missing from 0528 to 0716 UTC.

July 20, 1998
Updated NOAA-14 and NOAA-11 coefficients.

July 20, 1998
NOAA-14 data missing from 0517 to 0658 UTC.

July 21, 1998
Installed new software to check incoming SSU information and reject it if it is
inconsistent.

July 21, 1998
NOAA-11 data missing from 1036 to 1219 UTC.

July 22, 1998
NOAA-11 data missing from 0402 to 0506 UTC.

July 23, 1998
NOAA-14 data missing from 0254 to 0436 UTC.

July 24, 1998
NOAA-11 data missing from 0446 to 0602 UTC.

July 27, 1998
Updated NOAA-14 and NOAA-11 coefficients.

July 27, 1998
Noted that RTOVS products and archive define nighttime as those occasions when the
solar zenith angle is greater than 90 degrees.

July 28, 1998
NOAA-11 data missing from 0145 to 0334 UTC

Julyl 29, 1998
NOAA-11 data missing from 0000 to 0041 and from 1449 to 1533 UTC. NOAA-14 data
missing from 0000 to 0136 UTC.

July 30, 1998
NOAA-14 data missing from 0000 to 0123 UTC.

August 3, 1998
Updated NOAA-14 and NOAA-11 coefficients.




                                         D-57         NOAA POD Guide - Jan. 2002 Revision57
August 4, 1998
NOAA-11 data missing from 0258 to 0440 UTC.

August 5, 1998
NOAA-11 data missing from0146 to 0334 UTC.

August 6, 1998
NOAA-11 data missing from 1033 to 1221 UTC.

August 8, 1998
NOAA-11 data missing from 0524 to 0616 and from 2318 to 0050 UTC on August 9.

August 9, 1998
NOAA-14 data missing from 1951 to 2135 UTC.

August 10, 1998
NOAA-11 data missing from 1138 to 1223 and from 2341 to 0119 UTC on August 11.

August 11, 1998
NOAA-11 data missing from 0157 to 0319 UTC.

August 13, 1998
NOAA-11 data missing from 0155 to 0338 UTC.

August 17, 1998
Updated NOAA-14 coefficients.

August 18, 1998
Updated NOAA-11 coefficients.

August 18, 1998
NOAA-14 data missing from 2139 to 0810 UTC on August 19 due to a processing
problem.

August 24, 1998
Updated NOAA-14 and NOAA-11 coefficients.

August 26, 1998
Corrected SSU Smoother was placed in production. Problem isolated to improper
accessing of the file. TOVS Smoother was removed. However, there is still a problem
producing retrievals at the extreme polar locations.

August 27, 1998
NOAA-11 data missing from 0843 to 0923 and from 1356 to 1520 UTC. NOAA-14 data
missing from 1159 to 1321 UTC.




                                      D-58         NOAA POD Guide - Jan. 2002 Revision58
August 31, 1998
Updated NOAA-14 and NOAA-11 coefficients.


September 1, 1998
NOAA-11 data missing from 1158 to 1344 and from 2202 to 2350 UTC. NOAA-14 data
missing from 2038 to 2223 UTC due to incorrect time codes in the input data.

September 2, 1998
Reduced volume of NOAA-14 data from 09/01-02 due to incorrect TIP time codes in the
Level 1b files.

September 3, 1998
NOAA-11 data missing from 0611 to 0734 UTC.

September 4, 1998
NOAA-11 data missing from 0404 to 0551; and 1136 to 1303 UTC.

September 6, 1998
NOAA-14 data missing from 0818 to 0959 UTC

September 7, 1998
NOAA-11 data missing from 1102 to 1223 UTC.

September 8, 1998
Updated NOAA-14 and NOAA-11 coefficients.

September 13, 1998
NOAA-11 data missing from 0110 to 0156 UTC.

September 15, 1998
Updated NOAA-14 and NOAA-11 coefficients.

September 16. 1998
NOAA-14 data missing from 0949 to 1117 UTC.

September 17, 1998
NOAA-14 data missing from 1920 to 2104 UTC.

September 18, 1998
Installed updated EFNDSS in SPGDVR as final fix to SSU problem.

September 19, 1998
NOAA-11 data missing from 2332 on September 19 to 0121 UTC on September 20.

September 20, 1998



                                      D-59        NOAA POD Guide - Jan. 2002 Revision59
NOAA-14 data missing from 0155 to 0339 UTC.

September 21, 1998
Updated NOAA-14 and NOAA-11 coefficients.

September 22, 1998
NOAA-14 data missing from 0258 to 0505 UTC.

September 24, 1998
Updated thresholds on NOAA-11 CDB.

September 26, 1998
NOAA-14 data missing from 1255 to 1429 UTC.

September 28, 1998
Updated NOAA-14 and NOAA-11 coefficients.

October 5, 1998
Updated NOAA-14 and NOAA-11 coefficients.

October 8, 1998
NOAA-11 data missing from 0431 to 0621 UTC.
October 11, 1998
NOAA-11 data missing from 0525 to 0622 UTC.

October 13, 1998
Updated NOAA-14 coefficients.

October 14, 1998
NOAA-14 data missing from 1438 to 1613 UTC.

October 18, 1998
NOAA-11 data missing from 1743 to 1923 UTC.

October 19, 1998
Updated NOAA-14 coefficients.

October 19, 1998
NOAA-11 data missing from 1107 to 1201 UTC.

October 21, 1998
Users were notified of a problem in the upper troposphere over Antarctica=s high terrain.
Problem stems from RTOVS=s improperly responding to the warming in the stratosphere
as spring progresses in that region. Problem expected to persist for another two weeks
then RTOVS will have automatically adjusted.




                                        D-60         NOAA POD Guide - Jan. 2002 Revision60
October 26, 1998
Updated NOAA-14 and NOAA-11 coefficients.

October 27, 1998
NOAA-11 data missing from 0023 to 0107 UTC.

October 28, 1998
Geopotential heights for the first 20 heights were improperly scaled. The first 9 heights
had been scaled by 10 twice instead of once and the 11th through 20th heights were not
scaled by 10 when they should have been. This was corrected at 1500 UTC.

November 1, 1998
NOAA-14 data missing from 0616 to 0752 UTC.

November 2, 1998
Updated NOAA-14 and NOAA-11 coefficients.

November 2, 1998
NOAA-11 data missing from 1753 to 2035 UTC.
November 6, 1998
NOAA-11 data missing from 1450 to 1544 UTC.

November 7, 1998
NOAA-11 data missing from 0559 to 0727 UTC.
NOAA-14 data missing from 0000 to 0900 UTC.

November 9, 1998
NOAA-11 data missing from 2329 to 0046 UTC on November 10.

November 11, 1998
NOAA-11 data missing from 0126 to 0633 and from 1531 to 0121 UTC on November
12.

November 12, 1998
NOAA-11 HIRS began exhibiting problems with calibration and higher than normal
orbital average current values from the scan motor.

November 12-13, 1998
Products from one Command Data Acquisition Station were sporadic.

November 12, 1998
NOAA-11 data missing from 0510 to 0622 UTC.

November 15, 1998
NOAA-11 data missing from 0116 to 0304 UTC




                                         D-61         NOAA POD Guide - Jan. 2002 Revision61
November 16, 1998
Updated NOAA-14 and NOAA-11 coefficients.

November 16, 1998
NOAA-11 data missing from 1427 to 2100 UTC due to data corruption.

November 17, 1998
NOAA-11 data missing from 0051 to 0700 and from 1759 to 2048 UTC.

November 18, 1998
NOAA-11 data missing from 0038 to 0647 and from 1757 to 2036 UTC.

November 19, 1998
NOAA-11 data missing from 1026 to 1214 UTC.

November 21, 1998
NOAA-11 data missing from 1820 to 1958 UTC.

November 22, 1998
NOAA-11 data missing from 1138 to 1307 UTC.

November 23, 1998
Updated NOAA-14 and NOAA-11 coefficients.

November 24, 1998
NOAA-11 data missing from 1223 to 1306 UTC.

November 28, 1998
NOAA-14 data missing from 1627 to 1844 UTC.

November 30, 1998
Updated NOAA-14 and NOAA-11 coefficients.

November 30, 1998
NOAA-11 data missing from 1453 to 1642 and from 1837 to 1946 UTC.

December 1-18, 1998
All software migrated from the mainframe computer to the Amdal Enterprise Server.

December 1, 1998
NOAA-11 data missing from 1441 to 1630 UTC.

December 2, 1998
NOAA-11 data missing from 0205 to 0353 UTC.

December 6, 1998



                                      D-62         NOAA POD Guide - Jan. 2002 Revision62
NOAA-11 data missing from 1738 to 1913 UTC.

December 7, 1998
Updated NOAA-14 and NOAA-11 coefficients.

December 7, 1998
NOAA-11 data missing from 0345 to 0608 UTC.

December 9, 1998
Cloud product upgrade (experimental product) implemented.

December 12, 1998
NOAA-11 data missing from 1403 to 1552 UTC.

December 14, 1998
Updated NOAA-14 and NOAA-11 coefficients.

December 16, 1998
NOAA-14 data missing from 0450 to 0613 UTC.

December 17, 1998
NOAA-11 data missing from 1440 to 1631 UTC.

December 18, 1998
NOAA-14 data missing from 0028 to 0204 UTC.

December 19, 1998
NOAA-11 data missing from 1800 to 1949 UTC.

December 21, 1998
Updated NOAA-14 and NOAA-11 coefficients.

December 22, 1998
NOAA-11 data missing from 1903 to 2011 UTC.

December 23, 1998
NOAA-11 data missing from 0758 to 0947 UTC.

December 24, 1998
NOAA-14 data missing from 0812 to 0947 UTC.

December 26, 1998
NOAA-11 data missing from 1931 to 2117 UTC.

December 28, 1998
Updated NOAA-14 and NOAA-11 coefficients.



                                      D-63        NOAA POD Guide - Jan. 2002 Revision63
December 28, 1998
NOAA-11 data missing from 2043 to 2231 UTC.

January 1, 1999
NOAA-14 data missing from 0001 to 0109 UTC.

January 4, 1999
Updated NOAA-14 and NOAA-11 coefficients.

January 5, 1999
NOAA-11 data missing from 1929 to 2118 UTC.

January 6, 1999
Modified orbital processing: (1) expanded the possible high terrain channel combinations
and retrievals. (2) modified the gross temperature check. (3) Added the use of variable
distance windows. (4) added use of variable eignevectors across channels. (5) Added the
use of orbital node for the binning of radiosonde-retrieval match data. (6) Improved the
upper level check for radiosondes.

January 11, 1999
Updated NOAA-14 and NOAA-11 coefficients.

January 10, 1999
NOAA-11 data missing from 0733 to 0923 UTC.

January 13, 1999
NOAA-11 data missing from 1730 to 2119 UTC.

January 15, 1999
NOAA-14 data missing from 0223 to 0344 UTC.

January 18, 1999
NOAA-14 data missing from 0317 to 0459 UTC.

January 19, 1999
Updated NOAA-14 and NOAA-11 coefficients.

January 23, 1999
NOAA-14 data missing from 1559 to 1732 UTC.

January 25, 1999
Updated NOAA-14 and NOAA-11 coefficients.

January 31, 1999
NOAA-14 data missing from 1142 to 1243 UTC.



                                        D-64         NOAA POD Guide - Jan. 2002 Revision64
February 1, 1999
Updated NOAA-14 and NOAA-11 coefficient.

February 1, 1999
NOAA-14 data missing from 0212 to 0359 UTC.

February 2, 1999
NOAA-11 data missing from 0802 to 0936 UTC.

February 3, 1999
NOAA-11 data missing from 0000 to 0127 and from 0730 to 0923 UTC.

February 8, 1999
Updated NOAA-14 and NOAA-11 coefficients.

February 8, 1999
NOAA-14 data missing from 0000 to 2256 UTC.

February 9, 1999
NOAA-14 data missing from 0000to 2248 UTC.

February 12-15, 1999
Did not receive any forecast or radiosonde data due to serious computer problems at the
National Centers for Environmental Prediction (NCEP)

February 22, 1999
Updated NOAA-14 and NOAA-11 coefficients.

February 23, 1999
NOAA-11 data missing from 1448 to 1528 UTC.

February 26, 1999
At 0935Z, the NOAA-11 telemetry indicated the MSU scanner came to a stuck position.
Investigation of the quality of NOAA-11 soundings began, little to no data are being
processed due to the problem. No data was archived after 0818Z.

Problem with MSU on NOAA-11 is a broken drive belt for channels 3 and 4 (As reported
on March 16, 1999) . Both of the these channels are essential to RTOVS for processing
so RTOVS NOAA-11 processing has stopped.

March 1, 1999
Updated NOAA-14 coefficients.

March 8, 1999
Updated NOAA-14 coefficients.



                                        D-65         NOAA POD Guide - Jan. 2002 Revision65
March 9, 1999
NOAA-14 data missing from 0257 to 0359 UTC.

March 15, 1999
Updated NOAA-14 coefficients.

March 22, 1999
Updated NOAA-14 coefficients.

March 27, 1999
NOAA-14 data missing from 0220 to 0354 UTC.

March 29, 1999
Updated NOAA-14 coefficients.

March 31, 1999
NOAA-14 data missing from 1330 to 1510 UTC.

April 5, 1999
Updated NOAA-14 coefficients.

April 5, 1999
NOAA-14 data missing from 0214 to 0327 UTC.

April 7, 1999
NOAA-14 data missing from 2020 to 2204 UTC.

April 8, 1999
RTOVS system successfully tested as Year2000 compatible. Some modifications were
made, primarily to the reporting software.

April 12, 1999
Updated NOAA-14 coefficients.

April 19, 1999
Updated NOAA-14 coefficients.

April 23, 1999
NOAA-14 data missing from 0739 to 0915 UTC.

April 26, 1999
Updated NOAA-14 coefficients.

May 3, 1999
Updated NOAA-14 coefficients.



                                     D-66        NOAA POD Guide - Jan. 2002 Revision66
May 4, 1999
Archive modified to include polar redundant data. This was done to ensure good
coverage of the ozone hole.

May 10, 1999
Experimental cloud parameters were modified: (1) cloud amount calculation was changed
to use the proper channel pair instead of just HIRS channels 7 and 8. (2) cloud top
temperature is now used to compute the cloud amount.

May 10, 1999
Updated NOAA-14 coefficients.

May 17, 1999
Updated NOAA-14 coefficients.

May 24, 1999
Updated NOAA-14 coefficients.

June 7, 1999
Updated NOAA-14 coefficients.

June 9, 1999
Implemented correction to SSU mapping to eliminate a sporadic, localized problem on
the SSU map file.

June 14, 1999
Updated NOAA-14 coefficients.

June 21, 1999
Updated NOAA-14 coefficients.

June 27, 1999
NOAA-14 data missing from 0140 to 0324 UTC.

June 28, 1999
Updated NOAA-14 coefficients.

July 6, 1999
Updated NOAA-14 coefficients.

July 6, 1999
NOAA-14 data missing from 0538 to 0702 UTC.

July 7, 1999
NOAA-14 data missing from 1357 to 1512 UTC.



                                       D-67        NOAA POD Guide - Jan. 2002 Revision67
July 9, 1999
NOAA-14 data missing from 2311 to 0048 UTC on July 10.

July 11, 1999
NOAA-14 data missing from 0556 to 0748 UTC.

July 12, 1999
Updated NOAA-14 coefficients.

July 14, 1999
NOAA-14 data missing from 0500 to 0714 UTC.

July 15, 1999
Correct scaling of the layer precipitable water. Changed from centimeters to millimeters.

July 15, 1999
NOAA-14 data missing from 0513 to 0701 UTC.

July 19, 1999
Updated NOAA-14 coefficients.

July 22, 1999
NOAA-14 missing data from 0534 to 0724 and from 1407 to 2220 UTC.

July 25, 1999
NOAA-14 data missing from 1342 to 1510 UTC.

July 26 - August 1, 1999
Two cases of missing data due to various problems with some scan lines for the MSU as
well as other sounding instruments.

August 2, 1999
Fixed pre-processed frame problem.

August 2, 1999
Updated NOAA-14 coefficients.

August 9, 1999
Updated NOAA-14 coefficients.

August 16, 1999
Updated NOAA-14 coefficients.

August 16, 1999
NOAA-14 data missing from 2055 to 2239 UTC.



                                        D-68         NOAA POD Guide - Jan. 2002 Revision68
August 23, 1999
Updated NOAA-14 coefficients.

August 30, 1999
Updated NOAA-14 coefficients.

September 7, 1999
Updated NOAA-14 coefficients.

September 13, 1999
Updated NOAA-14 coefficients.

September 20, 1999
Updated NOAA-14 coefficients.

September 24, 1999
NOAA-14 data missing from 1739 to 1832 UTC.

September 27, 1999
Updated NOAA-14 coefficients.

October 4, 1999
Updated NOAA-14 coefficients.

October 4, 1999
NOAA-14 data missing from 0127 to 0313 UTC.

October 12, 1999
Updated NOAA-14 coefficients.

October 15, 1999
NOAA-14 data missing from 0812 to 0953 UTC.

October 18, 1999
Updated NOAA-14 coefficients.

October 22, 1999
NOAA-14 data missing from 1333 to 1509 UTC.

October 25, 1999
Updated NOAA-14 coefficients.

October 31, 1999
NOAA-14 data missing from 0000 to 0118 UTC.




                                   D-69       NOAA POD Guide - Jan. 2002 Revision69
November 1, 1999
Updated NOAA-14 coefficients.

November 8, 1999
Updated NOAA-14 coefficients.

November 8, 1999
NOAA-14 data missing from 0132 to 0317 UTC.

November 16, 1999
Updated NOAA-14 coefficients.

November 22, 1999
Updated NOAA-14 coefficients.

November 29, 1999
Updated NOAA-14 coefficients.

December 6, 1999
Updated NOAA-14 coefficients.

December 7, 1999
NOAA-14 data missing from 1454 to 1638 UTC.

December 8, 1999
NOAA-14 data missing from 0000 to 0048 UTC.

December 13, 1999
Updated NOAA-14 coefficients.

December 20, 1999
Updated NOAA-14 coefficients.

December 21, 1999
NOAA-14 data missing from 1714 to 1838 UTC.

December 27, 1999
Updated NOAA-14 coefficients.

December 28, 1999
NOAA-14 data missing from 1415 to 1554 UTC.

January 1, 2000
NOAA-14 data missing from 0001 to 0109 UTC

January 2, 2000



                                   D-70       NOAA POD Guide - Jan. 2002 Revision70
NOAA-14 data missing from 1500 to 1643 UTC.

January 4, 2000
Updated NOAA-14 coefficients.

January 4, 2000
NOAA-14 data missing from 1757 to 1918 UTC.

January 5, 2000
NOAA-14 data missing from 0744 to 0922 and from 1114 to 1239 UTC.

January 10, 2000
Updated NOAA-14 coefficients.

January 11, 2000
NOAA-14 data missing from 2313 to 0051 UTC on January 12.

January 18, 2000
NOAA-14 data missing from 0317 to 0459 UTC.

January 23, 2000
NOAA-14 data missing from 1559 to 1732 UTC.

January 24, 2000
Updated NOAA-14 coefficients.

January 31, 2000
Updated NOAA-14 coefficients.

February 7, 2000
Modified radiosonde-retrieval match software to accept matchups in the year 2000.

February 7, 2000
Updated NOAA-14 coefficients.

February 7, 2000
NOAA-14 data missing from 0433 to 0615 UTC.

February 8, 2000
NOAA-14 data missing from 0049 to 0225 and from 0611 to 0753 UTC.

February 14, 2000
Updated NOAA-14 coefficients.

February 16, 2000




                                       D-71         NOAA POD Guide - Jan. 2002 Revision71
Total number of first guesses was steadily decreasing. This was corrected today and a
satisfactory number of clear and cloudy first guesses were generated.

February 17, 2000
NOAA-14 data missing from 0000 to 2251 UTC.

February 18, 2000
NOAA-14 data missing from 0000 to 2241 UTC.

February 23, 2000
Updated NOAA-14 coefficients.

February 28, 2000
Updated NOAA-14 coefficients.

March 1, 2000
Modified the first guess library system to accept data in the year 2000, by removing date
checking. Modified the eigenvector update to accept data in the year 2000 by making
2000 the base year instead of 1998.

March 6, 2000
NOAA-14 data missing from 1621 to 1745 UTC.

March 9, 2000
NOAA-14 data missing from 0859 to 1033 UTC.

March 14, 2000
Updated NOAA-14 coefficients.

March 20, 2000
Updated NOAA-14 coefficients.

March 26, 2000
NOAA-14 data missing from 1457 to 1539 and from1733 to 1845 UTC.

March 27, 2000
Updated NOAA-14 coefficients.

March 28, 2000
NOAA-14 data missing from 0841 to 1015 UTC.

April 3, 2000
Updated NOAA-14 coefficients.

April 11, 2000
NOAA-14 coefficients were not updated due to software problems.



                                         D-72         NOAA POD Guide - Jan. 2002 Revision72
April 11, 2000
NOAA-14 data missing from 2235 to 2358 UTC.

April 18, 2000
Corrected operator component update to accept data from the year 2000 and beyond.

April 18, 2000
Updated NOAA-14 coefficients.

April 19, 2000
Corrected the archive job to ensure complete archive of products. Some data in past few
days were generated but did not get archived.

April 19, 2000
NOAA-14 data missing from 0220 to 0402 UTC.

April 24, 2000
Updated NOAA-14 coefficients.

May 1, 2000
Updated NOAA-14 coefficients.

May 8, 2000
Updated NOAA-14 coefficients.

May 9, 2000
NOAA-14 data missing from 1445 to 1534 UTC.

May 15, 2000
Updated NOAA-14 coefficients.

May 22, 2000
Updated NOAA-14 coefficients.

May 22, 2000
NOAA-14 data missing from 1530 to 1622 UTC.

May 30, 2000
Updated NOAA-14 coefficients.

June 5, 2000
Updated NOAA-14 coefficients.

June 12, 2000
Updated NOAA-14 coefficients.



                                        D-73        NOAA POD Guide - Jan. 2002 Revision73
June 19, 2000
Updated NOAA-14 coefficients.

June 26, 2000
Updated NOAA-14 coefficients.

July 13, 2000
Archive now completely done on an orbital basis. Hence, NESDIS Operations provide
NCDC with orbital files of RTOVS data instead of weekly tapes.

September 12, 2000
NOAA-14 data missing from 1447 to 1526 UTC.

September 14, 2000
NOAA-14 data missing from 0320 to 0352 UTC.

September 29, 2000
NOAA-14 data missing from 1501 to 1614 UTC.

October 23, 2000
NOAA-14 data missing from 1320 to 1502 UTC.

October 25, 2000
NOAA-14 data missing from 2104 to 2247 UTC.

October 26, 2000
NOAA-14 data missing from 1756 to 1920 UTC.

November 10, 2000
NOAA-14 data missing from 1459 to 1543 UTC.

November 16, 2000
NOAA-14 data missing from 1022 to 1205 UTC.

November 17, 2000
NOAA-14 data missing from 1955 to 0100 UTC on November 18.

November 18, 2000
NOAA-14 data missing from 1610 to 1714 and from 1802 to 2150 UTC. Missing data
related to problems with the Cross Strap Unit on NOAA-14.

November 19, 2000
NOAA-14 data missing from 0127 to 0234 UTC. Cross Strap Units were swapped on
NOAA-14 and problems with missing data subsided.




                                     D-74         NOAA POD Guide - Jan. 2002 Revision74
December 9, 2000
NOAA-14 data missing from 1250 to 1403 UTC.

December 19, 2000
NOAA-14 data missing from 0341 to 0523 UTC.

January 6, 2001
NOAA-14 data missing from 2030 to 2149 UTC.

January 22, 2001
NOAA-14 data missing from 2208 to 2344 UTC.

January 23, 2001
NOAA-14 data missing from 0348 to 0456 UTC.

January 26, 2001
NOAA-14 data missing from 0237 to 0319 UTC.

February 1, 2001
NOAA-14 data missing from 1523 to 1649 and from 2001 to 2040 UTC.

February 3, 2001
NOAA-14 data missing from 1454 to 1628 UTC.

February 5, 2001
Updated NOAA-14 coefficients.

February 12, 2001
Updated NOAA-14 coefficients.
February 17, 2001
NOAA-14 data missing from 0508 to 0651 UTC.

February 19, 2001
NOAA-14 data missing from 2318 to 0100 UTC on February 20.

February 20, 2001
Updated NOAA-14 coefficients.

February 26, 2001
Updated NOAA-14 coefficients.

February 27, 2001
NOAA-14 data missing from 1516 to 1643 UTC.

March 1, 2001
NOAA-14 data missing from 1303 to 1445 UTC.



                                    D-75        NOAA POD Guide - Jan. 2002 Revision75
March 5, 2001
Updated NOAA-14 coefficients.

March 12, 2001
Updated NOAA-14 coefficients.

March 19, 2001
Updated NOAA-14 coefficients.

March 26, 2001
Updated NOAA-14 coefficients.

April 2, 2001
Updated NOAA-14 coefficients.

April 9, 2001
NOAA-14 data missing from 1124 to 1207 UTC.

April 16, 2001
Updated NOAA-14 coefficients.

April 16, 2001
NOAA-14 data missing from 1359 to 1542 UTC.

April 23, 2001
Updated NOAA-14 coefficients.

April 30, 2001
Updated NOAA-14 coefficients.

May 1, 2001
NOAA-14 data missing from 0213 to 0351 UTC.

May 7, 2001
Updated NOAA-14 coefficients.

May 14, 2001
Updated NOAA-14 coefficients.

May 22, 2001
Updated NOAA-14 coefficients.

May 29, 2001
Updated NOAA-14 coefficients.




                                   D-76       NOAA POD Guide - Jan. 2002 Revision76
June 4, 2001
Updated NOAA-14 coefficients.

June 7, 2001
NOAA-14 data missing from 2149 to 2331 UTC.

June 8, 2001
NOAA-14 data missing from 0123 to 0254 UTC.

June 11, 2001
Updated NOAA-14 coefficients.

June 18, 2001
Updated NOAA-14 coefficients.

June 21, 2001
NOAA-14 data missing from 1056 to 1238 UTC.

June 25, 2001
Updated NOAA-14 coefficients.

July 2, 2001
Updated NOAA-14 coefficients.
July l2, 2001
NOAA-14 data missing from 0654 to 0836 UTC.

July 3, 2001
Stopped operational distribution of NOAA-14 data. Archive continued to allow overlap
of RTOVS NOAA-14 archive and ATOVS NOAA-16 archive.

July l3, 2001
NOAA-14 data missing from 0642 to 0824 UTC.

July 6, 2001
NOAA-14 data missing from 0410 to 0554 UTC.

July 9, 2001
Updated NOAA-14 coefficients.

July 10, 2001
NOAA-14 data missing from 0659 to 0841 UTC.

July 11, 2001
NOAA-14 data missing from 2142 to 2324 UTC.

July 15, 2001



                                      D-77         NOAA POD Guide - Jan. 2002 Revision77
NOAA-14 data missing from 0741 to 0922 and from 2235 to 0017 UTC on July 16.

July 16, 2001
Updated NOAA-14 coefficients.

July 23, 2001
Updated NOAA-14 coefficients.

July 26, 2001
NOAA-14 data missing from 0708 to 0850 UTC.

July 28, 2001
NOAA-14 data missing from 0643 to 0825 UTC.

July 29, 2001
NOAA-14 data missing from 0631 to 0813 UTC.

July 31, 2001
Updated NOAA-14 coefficients.

August 6, 2001
Updated NOAA-14 coefficients.

August 13, 2001
Updated NOAA-14 coefficients.

August 20, 2001
Updated NOAA-14 coefficients.

August 27, 2001
Updated NOAA-14 coefficients.

September 4, 2001
Updated NOAA-14 coefficients.

September 10, 2001
Updated NOAA-14 coefficients.

September 11, 2001
Some HIRS channels had drifted beyond the gross calibration limits. Processing was
stopped.

September 12, 2001
Calibration adjusted the limits and processing and archive were resumed.

September 17, 2001



                                        D-78         NOAA POD Guide - Jan. 2002 Revision78
Updated NOAA-14 coefficients.

September 24, 2001
Updated NOAA-14 coefficients.

October 1, 2001
Updated NOAA-14 coefficients.

October 9, 2001
Updated NOAA-14 coefficients.

October 15, 2001
Updated NOAA-14 coefficients.

October 19, 2001
End of RTOVS processing. The last data processed was from NOAA-14 from 0455 to
0648 UTC. This orbit has reduced coverage due to complications with the AVHRR
instrument affecting the delivery of data from the satellite.




                                    D-79        NOAA POD Guide - Jan. 2002 Revision79
Appendix E:           Historical Record of Significant Events Affecting the SST,
                      Radiation Budget, and Aerosol Products Produced from
                      TIROS-N series AVHRR Data

This appendix contains a record of events that affect the SST, Radiation Budget and
aerosol products generated by NOAA and also the SST Observation file generated by the
Navy. Accordingly, this appendix is divided into two subsections: E.1 contains the
changes made to NOAA products and E.2 has the change record for the Navy=s SST
Observation product.

E.1                   CHANGES MADE TO NOAA PRODUCTS

October 13, 1978
Launch of the TIROS-N spacecraft, the prototype for the third generation of polar-
orbiting operational environmental satellites. The TIROS-N series replaces the ITOS
series (i.e., NOAA-1 to NOAA-5).

December 4, 1978
Begin calculation and archive of sea surface temperatures (SST's) derived from TIROS-N
data. Equivalent black body temperatures are obtained from the 11 micrometer channel
of the AVHRR using the truncated normal technique on targets of 11 by 11 samples of 4
km resolution global area coverage (GAC) data. Gross cloud detection requires that the
AVHRR 11 micrometer channel and the HIRS/2 channel 8 (H8) (an 11 micrometer
channel) not differ by more than 2 degrees C after correction for the average difference
between the two channels (average difference is 1 degree C with the H8 being smaller
than the AVHRR 11 micrometer channel). Also the difference between H8 and H7 must
exceed 17 degree C. Primary cloud detection is performed with a discriminant classifier
determined by regression using data from November 15 and 16, 1978. Coefficients of the
discriminant classifier were determined by a global regression using the gross cloud tests
to determine the clear targets. The discriminant functions are as follows:

Type 129 (AVHRR and HIRS/2 coincident data available)
D= -0.9963863E-02 (Climatology - 290)
 +0.2248869E-01 (H8-H5)
 +0.2171421E-02 (H10-H11)
 -0.1852268E+00 (SEC sza -1)

Type 130 (AVHRR Data Only)
D= 0.2080572E-01 (AVHRR 11 micrometer Channel - Climatology)
 +0.3665414E-02 (Climatology-290)
 +0.4795260E-01 (SEC sza -1)

where SEC sza is the secant of the satellite zenith angle. All values in the discriminant
equation are in K. Climatology is the nearest 1 degree latitude/longitude grid point
climatological SST value for the month. The value of D must be between 0.98 and 1.20
for the target to be classified as clear. Clear 11 micrometer equivalent black body



                                           E-1         NOAA POD Guide - Jan. 2002 Revision1
temperatures are then corrected for the effects of atmospheric attenuation by using a
regression equation derived from data for November 15 and 16, 1978.

Using Northern Hemisphere Climatology for the ground truth data, the atmospheric
attenuation correction equations are as follows:
Type 129 (Coincident AVHRR and HIRS/2 Data)
DELTA T = -0.1498916E+02
      +0.4699983E-01 (100 km Field SST)
      +0.1256545E+00 (100 km Field SST - H11)
      +0.1047428E+01 (SEC sza -1)

Type 130 (AVHRR Only)
DELTA T = -0.3155946E+02
     +0.1177870E+00 (100 km Field SST)
     +0.1686770E+01 (SEC sza -1)

The 100 km and 50 km fields were initialized with December climatology.

January 1, 1979
End-of-Year problems caused some directory errors in the 7-day observation archive file
for this week.

February 1, 1979
Observations in the tropics are generally over 1 degree C too low. The cause is residual
cloud contamination, and it was decided to incorporate a neighbor check to eliminate
cloud contaminated observations. Began neighbor check procedure for all observations
between 20 degrees north and south. Each observation is compared with an average
temperature of surrounding observations. The observation is rejected if it differs from the
average by more than 1 degree C.

February 28, 1979
Formal end of ITOS operation. TIROS-N is designated as the operational satellite. The
TIROS-N SST archive, however, will be maintained beginning January 1, 1979.

May 9, 1979
Terminated neighbor check procedure in the tropics. Substituted stricter discriminant
function limits when the SST is above 297 K. The stricter limits are 1.02 to 1.20.

June 10, 1979
Repaired a logic problem in the SST retrieval module which prevented the retrieval of
SST's in the vicinity of the Date Line.

June 27, 1979
Launch of NOAA-A, designated NOAA-6 in orbit. This is the second satellite in the
TIROS-N series.




                                           E-2         NOAA POD Guide - Jan. 2002 Revision2
November 1, 1979
Beginning in mid April and continuing until Fall, accuracy above 30 degree North
latitude is poor. Current regression equations overcorrect for atmospheric attenuation in
the high latitudes in the summer hemisphere. Also, SST's in the vicinity of the northwest
coast of Africa are too high.

January 1, 1980
Heat budget analysis scheme changed. Mercator fields are now produced from the polar
stereographic fields. During 1979, the stereographic fields were derived from the
Mercator fields.

January 20, 1980
An on-board computer failure terminates TIROS-N data reception.

January 22, 1980
The NOAA-6 satellite, the second satellite in the TIROS-N series, is designated as the
operational satellite.

January 25, 1980
Began calculating SST's from NOAA-6 satellite. Regression coefficients were calculated
from January 22 and 23 data using Northern Hemisphere January climatology as ground
truth. Gross cloud detection tests are the same as TIROS-N. Discriminant classifier is as
follows:

Type 129 (Coincident AVHRR and HIRS/2)
D= -0.68785E-02 (Climatology - 290)
 +0.23452E-01 (H8-H5)
 +0.16013E-02 (H10-H11)
 -0.17712E+00 (SEC sza -1)

Type 130 (AVHRR only) Not Used

All temperatures are in K. Climatology is the nearest 1 degree latitude/longitude grid
point climatology value for the month.

Atmospheric attenuation correction equation was obtained by regression using Northern
hemisphere climatology for January as ground truth. The atmospheric attenuation
correction equation is:

Type 129 (Coincident AVHRR and HIRS/2)
DELTA T = -0.19640E-02 + 0.60360E-01 (100 km Field SST)
     +.15323E+00 (100 km Field SST - H11)
     +0.21380E+01 (SEC sza -1)

Type 130 (AVHRR only) Not Used




                                           E-3         NOAA POD Guide - Jan. 2002 Revision3
January 28, 1980
Observation accuracy has been degrading during the last few days. The problem has
been traced to the regression equation.

January 29, 1980
Changed regression for atmospheric attenuation correction. Ground truth was changed to
the 100 km field analysis temperature in the Northern hemisphere for January 20, 1980.
The new regression equation is as follows (Discriminant function was not changed):

Type 129 (Coincident AVHRR and HIRS/2)
 DELTA T = -0.2067618E+02
       +0.6683129E-01 (100 km SST)
       +0.1394463E+00 (100 km SST - H11)
       +0.2606292E+01 (SEC sza -1)

April 29, 1980
A slight increase in the IR channel space view noise has caused the loss of up to 16
percent of the data since April 11, 1980. The upper limit of the space view variance was
increased from 1 to 2 counts to accept the noisier data.

April 30, 1980
The threshold of the gross cloud detection test (the difference between HIRS channel 8
(the window channel) and channel 7 (the lower tropospheric channel), was decreased
from 17 degree C to 15 degree C. This essentially relaxes the cloud test at high latitudes
where it has been too restrictive (especially with the NOAA-6 data).

May 2, 1980
Version 2.0 of the Heat Budget data reduction module was implemented. This version
allows correct day/night decision in the creation of flux fields using data from a morning
satellite.

August 5, 1980
Implemented new cloud discrimination coefficients based on data passing the 15 degree
gross cloud test. The discriminant equation is now:
D= -0.78161E-02 (Climatology - 290)
  +0.22398E-01 (H8-H5)
  +0.41897E-02 (H10-H11)
  -0.15995E+00 (SEC sza -1)

The minimum threshold for D above 290 K surface temperature is 1.03, for the rest of the
Southern hemisphere it is 0.99, for the rest of the Northern hemisphere it is 0.98, (sza is
the Satellite zenith angle).

August 6, 1980
Implemented a bias correction to correct for the warm bias in high latitudes of the
summer hemisphere. The correction C is calculated as follows and added to the



                                           E-4         NOAA POD Guide - Jan. 2002 Revision4
calculated SST. C = Table Value - (H8-H7) where H8 and H7 are the temperatures
sensed in HIRS channel 8 (the window channel) and 7 (the lower tropospheric channel).
This correction is thus proportional to the lapse rate in the lower troposphere. The table
value is a function of the calculated SST before correction. The table is as follows:

 SST              Bias             SST             Bias             SST              Bias
                  Correction                       Correction                        Correction
 270              14.5             280             16.6             290              19.3
 271              14.6             281             16.9             291              19.4
 272              14.8             282             17.0             292              19.5
 273              14.9             283             17.3             293              19.6
 274              15.1             284             17.4             294              20.0
 275              15.4             285             17.8             295              20.5
 276              15.6             286             18.4             296              20.8
 277              15.8             287             18.9             297              21.1
 278              16.0             288             19.0             298              21.3
 279              16.3             289             19.1             299              21.0

August 26, 1980
It was discovered that the maximum atmospheric correction allowed is 8 degrees C.
Areas in the western tropical Pacific regularly have corrections greater than 8 degrees C.
Corrections as high as 15 degrees will be allowed for generating a regression tape used to
calculate the atmospheric correction coefficients. The limit will continue to be 8 degrees
C in the operational processing of SST.

January 20, 1980
An undetected disk I/O error on Thursday, November 20 resulted in a heat budget
observation dated July 28, 1984. Daytime longwave flux and absorbed solar energy
analyzed fields were set up for the erroneous date, interfering with the daily field analysis
for the next three days. To solve the problem, the field files were initialized. Nighttime
longwave flux fields were not affected by the erroneous observation; however, 10 hours
of nighttime data were lost in the field initialization.

January 31, 1980
Eight hours of data were lost due to an incorrect manual entry of the date on the
preprocessing computer.

January 24, 1981
The heat budget absorbed field was incorrect from January 17-24, 1981 due to a bad
program load module.

January 26, 1981
An error in the IBM 360 CPU resulted in loss of the 100 km SST analyzed field. The
field for January 25, 1981 was reloaded and the field generation program was rerun. An
incorrect data card did not allow any inclusion in this field of data from January 25, 1981.



                                            E-5          NOAA POD Guide - Jan. 2002 Revision5
February 6, 1981
The heat budget product network was run after midnight resulting in the calculation of a
heat budget analyzed field for the wrong date. The backup program was run too late.
The field for February 4, 1981 was lost.

August 19, 1981
The operational spacecraft was switched from NOAA-6 to NOAA-7. Three weeks of
operational parallel testing were conducted before the switch. Regression equations were
calculated using data collected between July 21, 1981 and July 23, 1981. Atmospheric
attenuation regression coefficients were calculated using the NOAA-6 satellite 100 km
analyzed field as ground truth. The gross cloud tests remain identical to NOAA-6. The
NOAA-7 cloud discriminant function is:

D = -.005565330 (Climatological SST - 290) + .02280071 (H8-H5)
       +.002125098 (H10-H11) -.1565646 (SEC sza-1)
where sza is the Satellite zenith angle. The atmospheric attenuation equation for NOAA-
7 is:

DELTA T= -13.37065
    +.03274177 (100 km analyzed field SST)
    +0.2143435 (100 km analyzed field SST - H11)
    +0.9215280 (SEC sza -1)

The bias correction was also changed for NOAA-7 and is being applied only in the
Northern hemisphere. The bias values are now:

 SST             Bias            SST             Bias             SST             Bias
                 Correction                      Correction                       Correction
 270             14.5            280             16.6             290             19.2
 271             14.6            281             16.9             291             19.4
 272             14.8            282             17.0             292             19.4
 273             14.9            283             17.3             293             19.4
 274             15.1            284             17.4             294             19.6
 275             15.4            285             18.6             295             20.5
 276             15.6            286             19.3             296             20.7
 277             15.8            287             19.7             297             21.9
 278             16.0            288             19.7             298             21.2
 279             16.3            289             19.3             299             20.9

August 25, 1981
Most of the observations for August 24, 1981 and August 25, 1981 had to be purged. A
faulty disk pack resulted in erroneous calibration coefficients and thus erroneous
observations. The NESDIS archive will not contain any erroneous data.

September 17, 1981



                                           E-6        NOAA POD Guide - Jan. 2002 Revision6
Calibration coefficients are erroneous for data from 0000Z to 2119Z. Bad data was
purged from the archive.

September 28, 1981
Calibration coefficients are erroneous for data from 0018Z to 1407Z. Bad data was
purged from the archive.

November 17, 1981
The operational technique for calculating sea surface temperatures was changed to a
multichannel technique. Separate algorithms are used for day and night observations.
The algorithm is denoted by the observation type. Type 151 is daytime operational
observations derived from the AVHRR instrument alone. Type 152 is nighttime AVHRR
operational observations. Daytime sea surface temperatures are calculated with a split-
window quadratic equation. The new equations for NOAA-7 are:

SST=1.046(T11) + 1.666(T11-T12) + 0.528(T11-T12) (T11-T12) - 286.48
where SST = sea surface temperature in Centigrade, T11=11 micrometer AVHRR
Channel temperature in Kelvin, and T12=12 micrometer AVHRR Channel temperature
in Kelvin.
Nighttime sea surface temperatures are calculated with a triple window equation:

SST= 1.0224(T11) + 1.00144(T3.7-T12) -278.515
where terms are the same as the daytime equation and T3.7=3.7 micrometer AVHRR
channel temperature in Kelvin. Sea surface temperatures are calculated from 8 km
resolution areas spaced about 25 km apart from all regions of the global ocean and the
larger inland seas such as the Caspian sea.

Two additional equations are used at night for cloud tests and intercomparison tests:

NIGHTTIME SPLIT-WINDOW
SST=1.07226(T11) + 1.7085(T11-T12) + 0.542(T11-T12)(T11-T12) - 294.27

NIGHTTIME DUAL-WINDOW
SST=1.0574(T11) + 1.5044(T3.7-T11) - 287.76

November 24, 1981
Changed precision of AVHRR daytime operational equation. New equation is as
follows:

SST= 1.0460(T11) + 1.6662(T11-T12) + 0.5285(T11-T12) (T11-T12) - 286.4595

November 27, 1981
A system error resulted in no SST observations for November 25, 1981.

November 30, 1981




                                           E-7         NOAA POD Guide - Jan. 2002 Revision7
The first monthly mean charts containing multichannel observations are dated November
30, 1981. These charts are derived partly from SSTs calculated with the former
operational technique and partly from the multichannel observations.

December 2, 1981
Implemented a low stratus nighttime cloud test. T11-T3.7 is not allowed to be greater
than 0.7 degrees Centigrade.

December 31, 1981
Produced the first monthly mean charts derived solely from multichannel data.

February 23, 1982
Changed daytime operational equation to a split-window linear equation:

SST= 1.0351(T11) + 3.046(T11-T12) - 283.9267
Began calculating 8 km density observations off Peru, in Gulf of Mexico, and off the East
Coast of the United States.

May 25, 1982
Changes were made to the regions covered by some of the 50 km SST analyzed fields
and the contour charts produced from these fields.

June 22, 1982
Starting in June 1982, the AVHRR 3.7 micrometer channel became progressively noisier.
The presence of noise caused some of the cloud detection tests to fail. With this failure,
erroneously low temperatures were introduced into the SST field analyses.

September 14, 1982
Changed analysis parameters in 100 km and 50 km analyzed fields to (1) Make the
analysis search area smaller, (2) Tighten the gradients, (3) Give observations near a grid
point a greater weight, (4) Accentuate 5 degree contours, and (5) Use more accurate
land/sea tags. A visible cloud threshold table is now being used for cloud discrimination
during the day. This table was derived with channel 2 albedos from January 1982.

September 15, 1982
Changed nighttime operational equation to one derived with corrected NOAA-7 filter
functions and a larger set of buoys to derive a bias correction (second bias correction).
The operational nighttime equation is the Nighttime Triple Window SST equation. The
daytime equation was unchanged.

NIGHTTIME TRIPLE WINDOW SST:
SST = 1.0239 (T11) + 0.9936 (T3.7-T12) - 278.46

NIGHTTIME SPLIT WINDOW SST:
SST = 1.0527 (T11) + 2.6272 (T11-T12) - 288.23




                                           E-8         NOAA POD Guide - Jan. 2002 Revision8
VOLCANO TRIPLE WINDOW SST:
SST = 1.9708 (T3.7- T11) + .9675 (T12) -260.46

The volcano triple window SST equation proved to be erroneous and was changed on
1/24/83.

October 13, 1982
The noise in channel 3 (3.7 micrometer channel) has increased substantially during the
last few months. The channel 3 uniformity test was turned off to obtain more coverage.

October 27, 1982
Noise in Channel 3 has caused loss of both day and night data. Increased noise limit so
data will not be lost during the day and put in a 15 count Channel 3 uniformity test at
night.

November 1, 1982
Errors uncovered in the daytime search pattern were fixed. Observation density is now
increased in high density areas.

November 17, 1982
Changed nighttime operational algorithms to use a 4 x 4 unit array (i.e., make 16 km
resolution SST's). This is an increase from the normal 2 x 2 (8 km) arrays. There is no
channel 3 (3.7 micrometer channel) uniformity test and the channel 4 (11 micrometer
channel) uniformity threshold is increased from 2 to 4 counts.

December 8, 1982
Increased density of observations along the U.S. West Coast.

December 15, 1982
Changed nighttime gross cloud test from channel 3 to channel 4. Increased the noise
limit for Channel 3.

December 22, 1982
Lost all but one orbit during December 19-20, 1982. No observations were produced
because calibration coefficients were in error.

January 24, 1983
Changed one of the SST intercomparison test equations from the volcano triple window
to the dual window equation.

DUAL WINDOW SST:
SST = 1.0063 (T3.7) + 0.4481 (T3.7-T11) - 272.47

February 3, 1983
Changed the daytime multichannel equation to the second bias correction version.




                                           E-9        NOAA POD Guide - Jan. 2002 Revision9
DAYTIME SPLIT-WINDOW
SST=1.0209(T11) + 2.5438(T1-T12) - 279.23

March 1, 1983
Implemented new coefficients for radiation (Heat) Budget calculations.

May 10, 1983
Began using high resolution land/sea tags around U.S. coast. Observations can now be
obtained as close as 10 km to land (closest observation allowed previously was 50 km to
land). Changed daytime SST search pattern in the observation calculation to prevent
duplicate observations from adjacent targets.

July 25, 1983
Electronic interference in the 3.7 micrometer channel (channel 3) has decreased the
accuracy of nighttime observations. No more nighttime observations will be produced.

August 2, 1983
Updated radiation budget coefficients.

August 14, 1983
Implemented the relaxed visible cloud threshold test in the daytime algorithm. If no
observations are obtained with the normal daytime algorithm, a search is made for the
warmest spot, the IR channel 4 uniformity test (2 count threshold) is performed along
with the visible channel 2 uniformity test and the visible cloud threshold is relaxed by
multiplying it by 1.5. Many more daytime observations are produced with this
procedure.

August 23, 1983
Added high density observation areas along the Alaskan coast, the entire Gulf of Mexico,
the East Coast of Australia, and the Coast of South Africa.

September 20, 1983
AVHRR IR channels on NOAA-7 turned off for outgassing. No SST's will be produced
for a week.

September 27, 1983
AVHRR NOAA-7 IR channels turned on at 1328Z. The noise in channel 3 was reduced
from 16 counts to 1.36 counts.

September 28, 1983
NOAA-7 SST made operational at 2200Z for both day and night data. No radiation
budget field was produced for September 27, 1983.

October 6, 1983
A disk crash resulted in the loss of 3 days of 100 km analyzed fields.




                                          E-10         NOAA POD Guide - Jan. 2002 Revision10
October 10, 1983
Reliability of daytime and nighttime observations have now been made equal. Previously
the nighttime reliability factor was only 3/4 of the daytime factor. This reliability factor
is used in the field analyses. The accuracy of the nighttime rms differences against buoys
are under 1 degree C.

November 29, 1983
Implemented a new multichannel equation for daytime observations. This is the third
bias correction equation:

SST= 1.0346 (T11) +2.5779 (T11-T12) - 283.21

December 1, 1983
Added Japanese Coast, Mediterranean, Hawaii to areas with high-resolution land/sea tags
and high-density observations.

December 9, 1983
Took out Hawaii high-density observation area. Too many observations are being
produced in this clear area. The limits of the current system have been reached.
December 13, 1983
Took out part of Sargasso Sea high-density observation area.

February 1, 1984
Changed nighttime multichannel equations to use the third bias corrected equations. The
equation used for operational SST is the triple window equation:

TRIPLE WINDOW SST:
SST= 1.0170 (T11) + 0.9694 (T3.7-T12) -276.58
The other two equations used in the SST intercomparison test are:
DUAL WINDOW SST:
SST= 1.5018 (T3.7) - 0.4930 (T11) - 273.34
SPLIT WINDOW SST:
SST= 3.6139 (T11) - 2.5789 (T12) -283.18

February 24, 1984
Nighttime SST data lost during much of the period February 17-24, 1984 because
calibration coefficients were inaccurate due to warming of the AVHRR to reduce jitter.

March 28, 1984
Changed daytime multichannel algorithm to process AVHRR data out to 53 degree
satellite zenith angle (an increase from 45 degree ).

July 25, 1984
Changed reflectance threshold for day/night determination from 10 percent to 1 percent.
For targets with Solar Zenith angles between 75 and 90 degrees, the nighttime algorithm
will be used if the reflectance in channel 2 is less than 1 percent. Otherwise the target



                                          E-11         NOAA POD Guide - Jan. 2002 Revision11
will not be processed at all. Targets with Solar Zenith less than 75 degrees will always
be processed with the daytime algorithm. Targets with Solar Zenith greater than 90
degree will always be processed with the nighttime algorithm.

August 16, 1984
Changed nighttime algorithm to use a 3 x 3 unit array (instead of a 2 x 2) and a uniform
low stratus threshold of 0.4 degrees.

November 1, 1984
Terminated production of 500 km SST field. The October 1984 archive tape (written on
November 2, 1984) is the last tape to contain a file of 500 km fields.

November 19, 1984
Removed a software error in the observation archive program. Some high density blocks
for the past year and a half contain old data. These blocks have been cleaned up and the
problem should not recur.
December 9, 1984
On 12/5 the NOAA-7 spacecraft was given an incorrect command which caused the
satellite to tumble. The spacecraft was not recovered until late on December 8. Test
SST's were generated for a day, then made operational on December 9.

December 12, 1984
Launch of NOAA-9.

December 15, 1984
NOAA-7 AVHRR was heated causing loss of data due to calibration problems from late
December 14, 1984 to late December 15, 1984. Calibration has returned to normal.

January 2, 1985
On December 31, 1984 the navigation data for the AVHRR had a 9 second error. All
SST observations were mismapped by 54 km. Incorrect observations were sent out on
the GTS. On January 2, 1985, observations from December 31, 1984 were purged from
the observation archive file. The mislocated observations are not on the 7-day
observation archive tape.

February 5, 1985
NOAA-9 became the operational satellite for SST and radiation budget. The Radiation
Budget coefficients are:
ACOF=-4.454, BCOF=1.2409, CCOF=-.001083

The SST equations are (first bias correction):
DAYTIME SPLIT WINDOW:
SST= 3.6569 (T11) - 2.6705 (T12) - 268.92

NIGHTTIME TRIPLE WINDOW:
SST= 0.9825 (T3.7) + 0.9936 (T11) - 0.9825 (T12) - 269.66



                                         E-12         NOAA POD Guide - Jan. 2002 Revision12
The two other equations used in the nighttime intercomparison test are:
NIGHTTIME SPLIT WINDOW:
SST= 3.6836 (T11) - 2.690 (T12) - 270.42

NIGHTTIME DUAL WINDOW:
SST= 1.4951 (T3.7) - 0.5015 (T11) - 269.13
where SST is the sea surface temperature in Centigrade, T3.7, T11, T12 are the 3.7, 11,
12 micrometer temperatures in Kelvin, respectively.

April 8, 1985
Began processing orbital data sent via an intercomputer link between the new METSAT
DPSS IBM 4300 series ingest system and the mainframe NAS 9050/ 9070 computers.
The 4300 computers are used to preprocess the data and the 9050/9070 are used for
product production.

July 1, 1985
Began operational orbital processing of NOAA-8 radiation budget in addition to NOAA-
9.

July 29, 1985
Started using new Uniform Low Stratus Cloud Test in the SST operation: (T12-T3.7)
must be less than -0.6K to calculate an SST at night. The test used previously was (T11-
T3.7) must be less than 0.7K to calculate an SST at night.

September 9, 1985
Stopped processing NOAA-8 data when the spacecraft oscillator malfunctioned.

September 16, 1985
Started processing NOAA-8 data once again for radiation budget.

September 21, 1985
NOAA-8 earth location incorrect.

September 28, 1985
Terminated processing of NOAA-8 data - oscillator malfunctioned again.

October 3, 1985
Began direct ingest of NOAA-9 data on the new METSAT DPSS ingest system
hardware. Up until this time data were ingested on the old SEL 32/55 computers.

October 8, 1985
Started using daytime split window equation with 2nd bias correction:

DAYTIME SPLIT WINDOW:
SST = 3.6446 (T11) -2.6616 (T12) - 267.96



                                        E-13         NOAA POD Guide - Jan. 2002 Revision13
October 15, 1985
The maximum satellite zenith angle was increased from 45 degrees to 53 degrees for
nighttime satellite SST observations.

October 28, 1985
Nighttime algorithm now uses the 2nd bias corrected multichannel SST equations along
with terms containing the satellite zenith angle (sza). The maximum zenith angle used
for SST has been increased from 45 to 53 degrees in both the daytime and the nighttime
algorithms.

NIGHTTIME TRIPLE WINDOW:
SST = 0.9946 (T3.7) + 1.0059 (T11) - 0.9946 (T12)+ .465 (T3.7)(SEC sza-1)
      - .465 (T12) (SEC sza-1) + .403 (SEC sza) - 273.923

The two other equations used in the nighttime intercomparison test are:

NIGHTTIME SPLIT WINDOW:
SST = 3.7028 (T11) - 2.704 (T12) - .27 (T11) (SEC sza-1)
         + .27 (T12) (SEC sza -1) + .738 (SEC sza) - 273.418
NIGHTTIME DUAL WINDOW:
SST = 1.5249 (T3.7) - .5115 (T11) + .958 (T3.7) (SEC sza-1)
         - .958 (T11) (SEC sza -1) + 1.55 (SEC sza) - 276.57
In all these equations, SEC sza is the secant of the Satellite zenith angle.

December 7, 1985
Twelve hours of data were lost due to lack of disk space in the SST observation file.

December 31, 1985
The last 2.5 degree latitude/longitude monthly mean contour charts were produced for the
month of December 1985. This terminates this product. It has been replaced with
monthly mean SST charts produced by the NOAA Climate Analysis Center.

January 1, 1986
Changed format of all hardcopy SST charts. All charts are now produced as single charts
rather than a collection of chartlets which must be assembled to form the finished chart.
The 14 km charts became operational and are now being produced twice each week and
archived to tape once a month. These high resolution charts cover the contiguous U.S.
coastline. Monthly mean charts have been discontinued, however, digital monthly mean
fields still continue to be archived. The resolution of the monthly mean field being
contoured will be increased from 2.5 to 2.0 degree latitude/longitude squares.

February 4, 1986
Some data lost due to tape recorder problems at Wallops CDA station.

February 5, 1986



                                           E-14         NOAA POD Guide - Jan. 2002 Revision14
Some data lost due to tape recorder problems at Wallops.

February 10, 1986
Some data lost due to frame sync errors at Wallops.

February 18, 1986
Some data lost due to frame sync errors at Wallops.

March 24, 1986
The Multi-channel Sea Surface Temperature (MCSST) production was down from 8:15
pm Local March 13 to 1:00 am March 16 due to water damage in NESDIS computer
room. Lost partial data for March 14 and all data for March 15.
August 4, 1986
Changed the format of the weekly satellite SST Observation File to satisfy requirements
of the Tropical Ocean and Global Atmosphere (TOGA) project.

September 17, 1986
Launched NOAA-10, satellite ID (8), descending morning. This satellite will be used
initially only for radiation budget products - not MCSST products.

October 6, 1986
Implemented the non-linearity calibration corrections for AVHRR channels 4 and 5 for
NOAA-9. The AVHRR calibration was changed to use a zero radiance of space instead
of a negative radiance of space. The equations are as follows (note: sza is Satellite
zenith angle):

DAY SPLIT
SST = 3.6446(T11) - 2.6616(T12) - 267.96

NIGHT SPLIT
SST = 3.7228(T11) - 2.7186(T12)
      -0.27(SEC sza -1) x (T11-T12) +0.738(SEC sza -1)-274.3641

NIGHT DUAL
SST = 1.5331(T3.7) - 0.5143(T11) + 0.958(SEC sza-1)(T3.7-T11)
      +1.550(SEC sza-1) - 276.7163

NIGHT TRIPLE
SST = 1.0113(T11) + 0.9999(T3.7-T12) +0.465(T3.7-T12) (SEC sza-1)
      + 0.403 (SEC sza-1) - 274.9957

November 7, 1986
NOAA-9 calibration was changed back to using a negative artificial radiance by mistake.
No change was made in MCSST equations. MCSST accuracy was degraded.

December 10, 1986



                                        E-15          NOAA POD Guide - Jan. 2002 Revision15
Began processing Radiation Budget from NOAA-10 Level 1b AVHRR data
operationally. The histogram classes for the Outgoing Longwave Radiation (OLR) data
for NOAA-10 are:
1st class interval = values greater than 174
2nd class interval = values from 136 through 174
3rd class interval = values less than 136

Changed to the following:
Class 1 < 107
107 < Class 2 < 131
Class 3 > 131
Histogram Threshold value 174,136

Coefficients
ACOF = 4.092BCOF = 1.1904             CCOF = -.001025

December 15, 1986
Started generating 50 km SST Analysis Fields twice a week instead of once a week.

January 10, 1987
A new high-density SST area was added to the SST operation for the region 60N to 80N
latitude and 40W to 10E longitude.

January 20, 1987
Changed the SST unit array size for cloud detection and SST averaging at night from
2X2 to 3X3. Added a new day and night SST cloud test to reject very large T11-T12
differences which occur with thin cirrus clouds and cloud edges. This test rejects the unit
array if (T11-T12) >3.5K. During the day, a second new test rejects unit arrays if
T11<270K.

February 11, 1987
The NOAA-9 AVHRR resynced between 1548Z and 1720Z. One orbit was affected.

March 23, 1987
Implemented an updated version of the AVHRR orbital processing program to correct
errors in the radiation budget flux summary subroutine.

April 6, 1987
Changed the NOAA-9 SST unit array from 3X3 to 2X2 for the nighttime algorithm.

April 7, 1987
Implemented changes to the program which generates the WMO satellite observation
product which goes out on the GTS. Header product identifier codes were changed and
the satellite identifier was changed from 36 to 34 for NOAA -9 and from 37 to 35 for
NOAA-10.




                                         E-16         NOAA POD Guide - Jan. 2002 Revision16
April 10, 1987
Twelve orbits were lost during the last 3 days due to AVHRR sync problems. A manual
resync was done on orbit 6263.

April 19, 1987
SST unit array size was changed from 2X2 to 3X3 because of high noise levels.

May, 1987
In the aerosol experimental product, changed the triple minus split cloud screening
threshold to 5 degrees Kelvin to keep the Saharan dust from being called cloud.
June, 1987
Weekly composite contour maps of aerosol optical thickness over the oceans began being
archived at NOAA/NCDC, Asheville, NC. Also, aerosol optical thickness began being
stored in the satellite observation files of the TOGA MCSST Observation File Tapes at
NCDC (8-day Observation File).

July 16, 1987
Implemented new NOAA-9 bias corrected equations for day and night. This corrects
most of the MCSST accuracy degradation caused by the calibration procedure using a
negative radiance of space.

DAY SPLIT
SST = 3.4317(T11) - 2.5062(T12) - 251.2163

NIGHT SPLIT
SST = 3.6037(T11) - 2.6316(T12) - .27(T11-T12) x (SEC sza -1)
      +0.738(SEC sza-1) - 265.0117

NIGHT DUAL
SST = 1.484(T3.7) - 0.4978(T11) + 0.958(T3.7-T11) x (SEC sza-1)
      +1.55(SEC sza-1) - 267.2916

NIGHT TRIPLE
SST = 0.9679(T3.7) + 0.9789(T11-T12) + 0.465(T3.7-T12) x (SEC sza-1)
      + 0.403(SEC sza-1) - 265.6235

July 30, 1987
All oceanographic product system processing was down from 2300 Local July 27, 1987
to 1200 Local on July 29, 1987 due to computer outage (thunderstorm).

September 10, 1987
A revised NOAA-9 AVHRR orbital processing program was implemented with some
aerosol changes. The following changes were made:
       1) Required azimuth greater than or equal to 140 degrees
       2) Changes Optical Thickness (OT) scale for Griggs' table from 0.213 to 0.244.
       3) Required OT less than 2.44



                                        E-17        NOAA POD Guide - Jan. 2002 Revision17
       4) Implemented Earth/Sun distance correction to Channel 1 radiance.

October 8, 1987
A revised NOAA-10 AVHRR orbital processing program was implemented with changes
to the radiation budget flux summary subroutine.

October 16, 1987
Changed NOAA-9 calibration back to zero radiance of space. Calibration is now correct;
however MCSST accuracy is degraded again since MCSST equations were not changed.
January 1, 1988
Problems were encountered in the ingest software resulting from end of year switch over.
This resulted in gridding errors (on the GELDS tapes) for approximately 27 hours and
partial loss of Level 1b data. There were 25 minutes of NOAA-9 data and over four
hours of NOAA-10 data lost on January 1, 1988. The affected GELDS tapes were
regenerated with the correct grid information.

January 4, 1988
The Ingest Systems Branch discovered another gridding problem. This problem involved
the calculation of the rotation of the Earth (Greenwich Hour Angle). It was corrected
operationally starting with orbit 15782 for NOAA-9 and orbit 6747 for NOAA-10.

January 28, 1988
Implemented new coefficients for all MCSST equations for NOAA-9 day split and night
dual. SST accuracy is improved since correctly calibrated channel values were used in
the generation of these equations, and they are used with correctly calibrated data.

DAY SPLIT
SST = 3.6084(T11) - 2.6353(T12) - 265.4789

NIGHT DUAL
SST = 1.5258(T3.7) - 0.5118(T11) +0.958(T3.7-T11) x (SEC sza-1)
      + 1.55 (SEC sza -1) - 275.3739

February 25-28, 1988
Communications were out between SOCC and the CDA in Gilmore Creek, AK which
resulted in the loss of approximately 50% of the Level 1b GAC data for the NOAA-9 and
NOAA-10 satellites.

March 30, 1988
Implemented new equations for NOAA-9 night split and night triple. MCSST accuracy
back to normal for day and night measurements.

NIGHT SPLIT
SST = 3.7051(T11) - 2.7057(T12) - 0.27(T11-T12) x (SEC sza-1)
      + 0.73(SEC sza-1) - 273.0323




                                        E-18         NOAA POD Guide - Jan. 2002 Revision18
NIGHT TRIPLE
SST = 0.9951(T3.7)+1.0065(T11) - 0.9951(T12)
      + 0.465(T3.7-T12)x(SEC sza-1) + 0.403(SEC sza-1) - 273.661

March 1988
To fix the overestimate of Optical Thickness (OT) over open oceans in the aerosol
experimental product, implemented the following:
        1) Removed Channel 1 radiance offset (set to 0) and 2) Set OT =0 if OT less than
0.
May 1, 1988
Implemented reflectance models in processing radiation budget. Used weighted
combination of Channels 1 and 2 with bidirectional and directional models.

August 11, 1988
Changed climatology test threshold for NOAA-9 from 7 to 10 degrees for all algorithms.

August 15-23, 1988
No AVHRR Level 1b IR channels archived.

August 31, 1988
Changed NOAA-9 unit array size to 3x3 for nighttime algorithm.

September 24, 1988
Launch of NOAA-11.

September 27, 1988
Turned off archive of ship observations in the TOGA SST Observation File Archive.

October 19, 1988
Changed unit array size for NOAA-9 to 2x2 at night.

November 1, 1988
All Level 1b data lost for all three satellites (NOAA-9, NOAA-10, and NOAA-11) from
October 29 1545Z to October 30 0314Z due to ingest computer problems.

November 8, 1988
NOAA-9 turned off. NOAA-11 became operational satellite for producing SST,
Radiation Budget, and Experimental Aerosol. Equations being used are listed under
November 17, 1988 entry. The Nighttime Thermal IR Cloud Tests, which compared the
actual T3.7 and T11 temperatures with values predicted from T11 and T12 temperatures,
respectively, were discontinued. The aerosol product continued to use NOAA-9 (Griggs')
table look-up code.

November 14, 1988
Lost MCSST observations for 3 days November 11-13, due to disk file problem.




                                        E-19          NOAA POD Guide - Jan. 2002 Revision19
November 17, 1988
Implemented MCSST equations and corrected central wave numbers for NOAA-11.
These equations were derived using data corrected with the original non-linearity
calibration correction tables for channels 4 and 5. These tables were obsolete and were
updated just prior to launch of NOAA-11. The original tables were used, however, until
September 27, 1989. If these equations are used with AVHRR data corrected with the
original non-linearity tables, the resulting SST's are correct.

DAYTIME:
SPLIT-WINDOW MCSST
SST = 0.9712(T11) + 2.0663(T11-T12) + 1.8983(T11-T12) x (SEC sza-1)
      -1.9790(SEC sza-1) -264.79

NIGHTTIME:
SPLIT-WINDOW MCSST
SST = 0.9843(T11) + 2.0942(T11-T12) + 2.0994(T11-T12) x (SEC sza-1)
      - 1.1838(SEC sza-1) - 268.74

DUAL WINDOW MCSST
SST = 1.00036(T11) + 1.6879(T3.7-T11) + 0.2550(T3.7-T11)x(SEC sza-1)
      + 1.4995(SEC sza-1) - 271.25

TRIPLE WINDOW MCSST
SST = 0.9900(T11) + 0.9528(T3.7-T12) + 0.6335(T3.7-T12)x(SEC sza-1)
      + 0.5215(SEC sza-1) - 269.22

December 21, 1988
Turned on flag to append HIRS data for day and night algorithms for NOAA-11 SST
observations.

December, 1988
Satellite observation files with aerosol optical thickness appended (in the same format as
the SST 8-day Observation File) began to be stored on separate Aerosol Observation File
Tapes at NCDC.

January 16, 1989
Switched to the NOAA-11 aerosol look-up table (STX Dave Code) but had errors in the
code.
       1) Removed azimuth greater than or equal to 140 degree requirement
       2) Set Optical Thickness (OT) = 0.213 for normalized value

January 19, 1989
Corrected error in aerosol code implemented on 1/16/89. Chart quality is poor.
Discovered striping in charts over open ocean tropics. Appeared to be orbit related.
Concluded that it was due to specular reflection. Discovered that the STX code should be
normalized to OT=0.198, rather than OT=0.213.



                                         E-20         NOAA POD Guide - Jan. 2002 Revision20
January 26, 1989
Changed the threshold values for the three histogram class intervals for NOAA-11 in the
Radiation Budget.

Class 1 < 123
123 < Class 2 < 151
Class 3 > 151
Histogram class thresholds are changed as follows:
NOAA-11 174,136 to 151,123
NOAA-10 151,123 to 131,107

February 2, 1989
Stopped appending HIRS data for daytime algorithm for NOAA-11.

February 16, 1989
To fix the aerosol problems found on 1/19/89, the following was implemented:
        1) OT=0.198 for normalized value.
        2) Satellite zenith angle less than 70 degrees (was < 53 degrees); this fills gaps in
        seven day coverage)
        3) GAMMA (half angle of specular reflection cone) must be greater than 40
degrees.

March 2, 1989
Found error preventing the aerosol 53 degree cut-off from being replaced by 70 degrees,
and fixed the error. However, other restriction in the data processing limit the maximum
satellite zenith to 60 degrees.

March 9, 1989
NOAA-11 Visible Cloud Threshold Table implemented, replacing the NOAA-9 table.
This is applicable to SST and aerosol operations.

March 13, 1989
Solar flare caused NOAA-10 and NOAA-11 to lose attitude control.

April 2, 1989
No TOVS Level 1b data archived. Computer clock problems caused by switch from EST
to EDT.

April 5-6, 1989
Degraded S/N ratios for Wallops passes. Antenna undergoing maintenance work.

April 6, 1989
Power outage in DPSS from 0300-1600 Local time.

April 6, 1989



                                           E-21         NOAA POD Guide - Jan. 2002 Revision21
Changed research density from 15 SST observations per 1/2 target to 8 observations per
1/2 target for NOAA-11 daytime SST algorithm. Changed search pattern to correspond
to this.

April 18, 1989
Began applying the triple minus split (TMS) test to 157 observations (operational SST
observations) as has always been done with 158 observations in the aerosol operation.
The Visible Cloud Threshold Table was relaxed by a factor of 8.
May 25, 1989
The Nighttime Outlier Rejecter Test was implemented in the SST operation. This cloud
test, which follows all the others, is a joint test; i.e. both parts must fail for rejection of
the observation:

Part 1 (HIRS TEST): [3.5-0.2333(HIRS8-HIRS7)+0.038446 x FLD
        + 1.612(SEC sza-1)]>0.25 fails the test
Part 2 (FIELD/CLIMATOLOGY TEST): [2 x (FLD-MCSST) + (CLIM -
MCSST)]/3>3.0
         fails the test
where:
FLD=the satellite 100 km analyzed field SST from the previous day.
CLIM = the current month's climatological SST value
SEC sza = secant of the Satellite zenith angle
HIRS8, HIRS7 = HIRS channel 6 and 19 temperature in K, respectively
MCSST = multichannel SST using the nighttime operational equation

May 31, 1989
NOAA-10 outgassing from May 30 through June 8. Turned off all Radiation Budget jobs
for this time period. No data available during this time.

June 8, 1989
Changed NOAA-10 three class histogram threshold values from 131,107 back to 151,123
in the radiation budget system.

June 8, 1989
Turned all Radiation Budget jobs back on after outgassing of NOAA-10 satellite
completed.

June 29, 1989
All tapes for SST Matchup Database (SSTMCH) from February 1982 to present, SST
Independent Buoy Data (SSTIND) from November 1978 to present, and SST Statistics
and Verification data (SSTSAV) from April 1979 to present were sent to SSB for
permanent archiving. SSB will now receive the original tapes for these QC/Verification
products.

July 25, 1989




                                            E-22          NOAA POD Guide - Jan. 2002 Revision22
A disk pack being used by an operational program was taken offline without prior notice.
Impact of this was loss of SSTOBS being transferred over the GTS system to WMO. A
new disk pack was put into place and new JCL built to correct problem.

July 28, 1989
Wallops CDA was hit by lightning. Did not receive any data from Wallops because of
this.

July 1989
The monthly mean contour maps of aerosol optical thickness began to be archived at
NCDC. Also, monthly Aerosol Analysis/Validation Tapes began being archived at
NCDC. They contain: Daily Summary Files - statistics on each day's observations for
648 ten degree Lat/long boxes; Daily Extreme Event Files - each satellite observation file
where optical thickness exceeds 0.2; Weekly Analyzed Field File - optical thickness
analyzed at 110 km resolution (used to produce contour maps); Monthly Averaged
Analyzed Field File - average of weekly field files; Validation File - contains satellite
observation and ground-truth data files at times and locations where matches within 3
hours and 300 km have occurred.

August 8, 1989
Changed residence time of data in SST Matchup Database from 62 to 45 days due to
space problems.

September 27, 1989
Implemented correct channel 4 (11 micrometer channel) non-linearity calibration lookup
table along with new MCSST coefficients for NOAA-11. These new equations should be
used with data calibrated with the correct non-linearity calibration table.

DAYTIME:
SPLIT-WINDOW MCSST
SST = 1.01345(T11) + 2.659762(T11-T12) + 0.526548(T11-T12)x(SEC sza-1) - 277.742

NIGHTTIME:
SPLIT-WINDOW MCSST
SST = 1.052(T11) + 2.397089(T11-T12) + 0.959766(T11-T12)x(SEC sza-1) -
288.670474

DUAL-WINDOW MCSST
SST = 1.03432(T11) + 1.347423(T3.7-T11) +0.953042(T3.7-T11)x(SEC sza-1) -
280.794042

TRIPLE-WINDOW MCSST
SST = 1.036027(T11) + 0.892857(T3.7-T12) + 0.520056(T3.7-T12)x(SEC sza-1) -
282.373967

Degrees Kelvin in and degrees Celsius out.



                                         E-23         NOAA POD Guide - Jan. 2002 Revision23
November 28, 1989
Implemented a revision of the SST orbital processing program which averages the on-
board calibration target blackbody temperatures for the 11 and 12 micrometer channels
(i.e., channels 4 and 5). Ten consecutive data points in each of 11 scans are averaged to a
single count value which is then converted to temperature. The calibration blackbody
temperatures are used in the non-linear calibration correction procedure.

November 28, 1989
Discontinued appending the HIRS channel data to the nighttime SST observations.
Removed the latitude/longitude field printout program from the operational job stream,
because this product is no longer required.

January, 1990
Aerosol Optical Thickness product was deemed "operational."

January 25, 1990
Began experimental operational production of a Hawaii 14 km analyzed SST chart
covering the Hawaiian Islands.

February 26, 1990
Began using a channel 4 uniformity test in operational daytime algorithm.
The threshold for rejection is 2 counts.

March 2, 1990
Implemented new CPSST (Cross Product SST) algorithm and new cross product
equations for NOAA-11 operational SSTs. T3.7, T11, T12 are AVHRR 3.7, 11 and 12
micrometer channel temperatures, respectively, in degrees Kelvin (i.e., temperatures in
Channels 3, 4, and 5, respectively). A new daytime MCSST Intercomparison Test was
also implemented. If the difference between the CPSST and MCSST exceeds 1.0 degree
C, then the observation is rejected.

CPSST DAY SPLIT
SST = [(0.19410(T12) - 48.15)/(0.20524(T12) - 0.17334(T11) - 6.25)]
  x (T11 - T12 + 1.32) + 0.94575(T12) + 0.60(T11-T12) x SEC sza -1) + 12.16

CPSST NIGHT TRIPLE
SST = [(0.16949(T11)-54.11)/(0.20524(T12) - 0.07747(T3.7)-41.60]
  x (T3.7-T12-6.73) + 0.97778(T11) + 1.41(SEC sza-1) + 14.17

CPSST NIGHT DUAL
SST = [(0.17115(T11) - 54.64)/(0.17334(T11) - 0.07747(T3.7)-30.94]
  x (T3.7-T11-3.64) + 0.98737(T11) + 1.59(SEC sza-1) + 11.38

CPSST NIGHT SPLIT
SST = [(0.19817(T12) - 49.15)/(0.20524(T12) - 0.17334(T11) - 6.10]



                                         E-24         NOAA POD Guide - Jan. 2002 Revision24
  x (T11-T12 +1.47) + 0.96554(T12) +0.96(T11-T12)(SEC sza-1)+6.02

Degrees Kelvin in and out.

April 18, 1990
Implemented new CPSST equations for NOAA-11.
Implemented the Thermal-IR Uniformity Test during the day. This test is the same as the
nighttime test with the same name. If all the unit array T11 temperatures do not agree
within 0.2K, then the unit array is rejected.

MCSST DAY SPLIT
SST = 1.0155(T11) +2.50(T11-T12) + 0.73(T11-T12)(SEC sza-1)-277.99

CPSST DAY SPLIT
SST = [(0.19069(T12)-49.16)/(0.20524(T12) - 0.17334(T11)-6.78)]
       x (T11-T12+0.789) + 0.92912(T12) +0.81(T11-T12)(SEC sza-1) - 254.18

CPSST NIGHT TRIPLE
SST = [(0.16835(T11) -34.32)/(0.20524(T12)-0.07747(T3.7)-20.01)]
       x (T3.7-T12+14.86)+0.97120(T11)+1.87(SEC sza-1) - 276.59

CPSST NIGHT DUAL
SST = [(0.17079(T11) - 58.47)/(0.17334(T11) - 0.07747(T3.7)-33.74)]
       x (T3.7-T11-6.44) +0.98530(T11) +1.97(SEC sza-1) -257.28

CPSST NIGHT SPLIT
SST = [(0.19596(T12) - 48.61)/(0.20524(T12) -0.17334(T11)-6.11)]
       x (T11-T12+1.46) + 0.95476(T12)+0.98(T11-T12)(SEC sza-1)-263.84
Degrees Kelvin in and Celsius out.

April 3, 1990
Changed the Phoenix target in the Target Matchup Data Base to 33.72N and -112.33W.
Added two targets: 8.5N, 4.5E and 3.22N, 60.03W.

June 2, 1990
No data available for NOAA-11 0900-2400Z and NOAA-10 0600-2400Z caused by fire
and power outage in SOCC.

June 4-7, 1990
Lost majority of SST observations for this period or inaccurate observations calculated
with wrong coefficients. All aerosol observations lost for this period. Data lost due to
incorrect job control language.

June 25, 1990
Began putting aerosol observations into SST Matchup Database.




                                         E-25         NOAA POD Guide - Jan. 2002 Revision25
July 2, 1990
Implemented new NOAA-11 radiation budget coefficients. These are:

                                 ACOF                    BCOF                     CCOF
         OLD                     -4.454                  1.2409                 -0.001087
         NEW                     -10.14                  1.2681                 -0.001117

July 11, 1990
Updated NOAA-10 orbital processing program to revise the calculation of available solar
energy at the North Pole and the subroutine BTWEEN which decides whether a point is
within a given geographic rectangle. Updated the NOAA-11 orbital processing program
to correct an interchange of the snow and desert scene IDs and the subroutine BTWEEN.
These changes affect the radiation budget system.

August 2, 1990
Began processing SSTs in high density mode (8 per target) for the region 10-30N and 10-
40W, in order to obtain more aerosol Matchup observations.

September 27, 1990
In the aerosol operation, Channel 1 gain was lowered by 5% which increases the albedo
in Channel 1 by 5%. Aerosol optical thickness will be increased by at least 5% after this
date.

September 30, 1990
SST observations were lost during the period 9/28-9/30. The reason is unknown since all
programs appear to be running correctly.

October 31, 1990
Changed the residence time of satellite-buoy matches from 45 days to 35 days.

November 22, 1990
Lost 15 orbits of NOAA-11 processing during the period 11/21-11/22. This was caused
by a job control language error.

November 27, 1990
Updated the SST orbital processing program to include in the SST observation output, the
calibration blackbody temperatures for the 11 and 12 micrometer channels (i.e., Channels
4 and 5). This will allow the channel temperatures stored in the observation output to be
recorrected for non-linearity calibration errors, if a more accurate correction is ever
developed.

January 7, 1991
Turned off the radiation budget system for NOAA-10 during outgassing.

January 15, 1991
Resumed NOAA-10 processing after outgassing which began 1/7/91.


                                          E-26        NOAA POD Guide - Jan. 2002 Revision26
January 31, 1991
After a successful parallel test, new SST cloud test thresholds were implemented
operationally. These are:
   T12-T3.7 low stratus test threshold = 0 degrees
        SST intercomparison test threshold = 1.5 degrees
        Satellite versus climatology comparison in HIRS cloud test,
                threshold = 2.5 degrees

February 14, 1991
In the aerosol system, the Naval Research Lab equation for SST correction due to
Saharan Dust replaced the Griggs' El Chichon temperature correction. Aerosol
observations from this date forward will have corrected SST's using the new scheme.
These corrected SST's are experimental. The equations are:

Old Griggs' equation:
DT = 0.084 + 6.32(tau)(SEC sza)
New NRL equation:
DT = 0.0 + 4.34(tau)(SEC sza)

where tau is the aerosol optical thickness measured by Channel 1 of the AVHRR.

March 27, 1991
Changed the aerosol SST correction coefficients to the following (this will affect aerosol
SST observations only):
DT = 5.158 (Tau)(SEC sza) -0.3

April 10, 1991
Replaced the CPSST equations with the Non-linear SST (NLSST) equations based on
February 1991 buoy matches. The NLSST DAY SPLIT is the operational equation
during the day, and the NLSST NIGHT TRIPLE is the operational equation at night. The
equations are:

NLSST DAY SPLIT
SST=0.94649(T11)+0.08412(Tsfc)(T11-T12)
      + 0.751(T11-T12)(SEC sza-1)-257.20

MCSST DAY SPLIT
SST=1.02455(T11)+2.45(T11-T12)+0.64(T11-T12)(SEC sza-1)-280.67

NLSST NIGHT TRIPLE
SST=1.0006T11+0.245(T3.7-T12)+0.02766(T3.7-T12)
      + 1.88(SEC sza-1)-272.36

NLSST NIGHT SPLIT
SST=0.96042(T11)+0.087516(Tsfc)(T11-T12) + 0.852(T11-T12)(SEC sza-1)-261.46



                                         E-27         NOAA POD Guide - Jan. 2002 Revision27
MCSST NIGHT DUAL
SST=0.99615(T11)+1.5866(T3.7-T11)+2.027(SEC sza-1)-270.20

MCSST NIGHT TRIPLE
SST=1.00946(T11)+1.041(T3.7-T12)+1.76(SEC sza-1)-275.2

where MCSST = linear multi-channel SST algorithm
      NLSST=non-linear SST algorithm
      Tsfc= 100 km analyzed field temperature from the previous day
      SEC sza = secant of the Satellite zenith angle
      T3.7, T11, T12 are the AVHRR channel brightness temperatures in Kelvin
      SST is the sea surface temperature in degrees Centigrade
      SPLIT = using the 11 and 12 micrometer channels
      DUAL = using the 3.7 and 11 micrometer channels
      TRIPLE = using the 3.7, 11, and 12 micrometer channels

April 10, 1991
In the SST operation, the maximum limit on the climatological and analyzed field SST
value used in the NLSST equation (i.e., Tsfc) is 28 degrees C. The 100 km analyzed field
SST from the previous day is used for Tsfc. In the absence of a 100 km analyzed field
SST, the daytime split window MCSST equation (as given above) is used to obtain the
Tsfc used in the NLSST equation. The threshold for the Channel 4-5 comparison test
was changed from 4.0 to 3.5 Kelvin.

May 6, 1991
In the SST operation, increased the density of SST observations to the research density
for the region enclosed by 50 to 70N and 10 to 50W.

May 15, 1991
The NOAA-D satellite was launched today from Vandenberg Air Force Base in
California.

June 15, 1991
Mount Pinatubo in the Phillipines erupted today sending substantial amounts of aerosols
into the stratosphere. These aerosols will have a substantial effect on the SST
measurements for the next two years.

June 17, 1991
Began testing NOAA-12 for morning satellite radiation budget in parallel with NOAA-
10.

June 28, 1991
Reduced the retention time of data in the Aerosol Extreme Events File form 35 days to 31
days. The Extreme Events File has been repeatedly overflowing.




                                         E-28         NOAA POD Guide - Jan. 2002 Revision28
July 2, 1991
A problem has occurred in the aerosol observation file. The directory of the file and the
data are in conflict. The file was restored with a backup from June 29, 1991.

July 9, 1991
Turned off the Relaxed Visible Channel Cloud Test in the NOAA-11 SST operation
starting with 12Z data. This action was taken in response to corrupted SST observations
in equatorial regions due to stratospheric volcanic dust from the June Mt. Pinatubo
eruptions.

July 31, 1991
Changed solar constant for the 3.7 micrometer channel filter to 4.436416 for NOAA-12.
Previously, the NOAA-11 value had been used.

August 1, 1991
The Aerosol Extreme Events file was enlarged from 2000 to 2500 records after repeated
overflows.

August 13, 1991
The operation program that produces SST and aerosol observations from both NOAA-10
and NOAA-11 was updated today.

August 15, 1991
To obtain additional data to analyze the effects of the Mt. Pinatubo eruption, production
of SST observation type 159 (relaxed visible cloud test observations) was resumed (they
had been discontinued on July 9, 1991); however, these observations are not accurate and
will not be used in the SST analyzed field production. The 159 type observations should
not be used for SST products by anyone until further notice.

August 26, 1991
The size of the Aerosol Extreme Events File was increased again from 2500 to 3000
records.

September 16, 1991
NOAA-12 replaced NOAA-10 as the operational morning descending satellite at 2218Z
on orbit 1780. The last orbit of NOAA-10 data that was processed operationally was
25961 which contained data from 2119Z to 2247Z.

October 1, 1991
The first operational NOAA-12 monthly radiation budget archive tape was produced for
the month of September.

October 3, 1991
Completed the testing of an equation to correct for the Pinatubo aerosols at night. This
"volcano" equation was implemented operationally today. Also increased the SST




                                         E-29         NOAA POD Guide - Jan. 2002 Revision29
intercomparison test threshold for nighttime SST to 2.0 degrees. The new equation is
(derived from July 1991 buoy matches):

MCSST NIGHT TRIPLE "VOLCANO" EQUATION
SST=1.011015(T12)+2.088810(T3.7-T11)+2.278617(SEC sza-1)-273.234
October 3, 1991
Replaced the CPSST Split-window equation in the aerosol algorithm with the operational
NLSST Split-window equation (which was implemented into the SST system on April
10, 1991).

October 18, 1991
Reduced retention period of data in the Aerosol Extreme Events File form 31 to 30 days,
in response to overflowing that file.

December 6, 1991
Replace the precipitable water calculation that has been stored in the spare halfword of all
SST observations to the NLSST Triple Window Night SST value. This will aid in the
study of the impact of the Pinatubo aerosols.

December 18, 1991
A program modification allowed the proper NLSST Triple Window SST value to be
placed in the spare halfword of the SST observations. Incorrect values were placed in the
spare halfword from December 6, 1991 until today.

December 31, 1991
Solved the problem of missing radiation budget orbits or partial orbits. This problem has
been in the system since the radiation budget operation was established.

January 3, 1992
The operational aerosol SST algorithm now uses the dual-window equation:

NLSST NIGHT DUAL
SST = 1.0202(T11) + 0.0512(Tsfc (T3.7-T11)) +2.42(SEC sza-1)-277.5

April 9, 1992
Updated all SST equations. Operational equations are now NLSST Day Split and
NLSST Night Dual. The other equations are used in the cloud tests like the SST
Intercomparison Test.

NLSST DAY SPLIT
SST=0.962191(T11)+0.083398(Tsfc)(T11-T12)+0.653750(SEC sza-1)(T11-T12)-
261.114

MCSST DAY SPLIT
SST=1.02015(T11)+2.320(T11-T12)+0.489(SEC sza-1)(T11-T12)-278.6




                                          E-30         NOAA POD Guide - Jan. 2002 Revision30
NLSST NIGHT DUAL
SST=1.032274(T11)+.055297(Tsfc)(T3.7-T11)+2.125323(SEC sza-1)-280.212

NLSST NIGHT SPLIT
SST=0.95554(T11)+.08435(Tsfc)(T11-T12)+1.1127(T11-T12)(SEC sza-1)-259.3

MCSST "VOLCANO" EQUATION
SST=1.00329(T12)+2.0476(T3.7-T11)+2.47(SEC sza-1)-270.9

July 7, 1992
The coefficients in the MCSST DAY SPLIT and NLSST NIGHT SPLIT equations were
modified slightly to:

MCSST DAY SPLIT
SST=1.020151(T11)+2.319730(T11-T12)+0.489092(T11-T12)(SEC sza-1.0)- 278.520

NLSST NIGHT SPLIT
SST=0.955535(T11)+0.084348(Tsfc)(T11-T12)+1.126894(T11-T12)(SEC sza-1)-
259.323

August 14, 1992
It was discovered that the climatology values in the 100 km Global Analyzed Field File
and the 50 km Regional SST Analyzed Field Files have not been updated since May
1992. The climatology values were updated today and will be updated automatically in
the future.

August 21, 1992
The aerosol observation file was destroyed on August 20. The file was reconstructed and
data was restored.

September 1, 1992
The radiation budget Available Solar Energy product was found to have an error. It was
corrected by changing two subroutines in the RADABS program.

September 8, 1992
New navigation software was implemented in the processing of the AVHRR 1b data.
AVHRR latitudes and longitudes are now more accurate. Orbital parameters are now in
the 1b header and are updated each orbit. Solar Zenith angle is more accurate now.

September 15, 1992
The density of SST observations calculated in the region 10S to 10N latitude and 100E to
70W longitude (through the dateline) was increased to the highest density.

September 17, 1992
The retention period of data in the SST Matchup Data Base was changed from 35 to 31
days.



                                        E-31         NOAA POD Guide - Jan. 2002 Revision31
September 24, 1992
New navigation software removed because some video data was being lost.
September 29, 1992
SST observations of type 159 (Daytime SSTs that pass the relaxed visible cloud threshold
table test) are once again being used in generating the SST Analyzed Field files (100 km,
50 km, and 14 km).

October 23, 1992
New navigation software was reimplemented.

November 9, 1992
A change was made in the SST processing program to trap and correct a calibration
problem that has been identified. Stray light from the sun, under certain conditions of
solar angles and spacecraft orbital position, has been striking the on-board black-body
calibration target. This is adversely affected the calibration of the 3.7 micrometer IR
channel (Channel 3). The last good calibration coefficients will be used while stray light
illuminates the calibration target. The 11 and 12 micrometer IR channels are not affected
because there is very little energy in reflected sunlight at these wavelengths.

December 15, 1992
After one month of parallel testing, the entire SST, radiation budget, and aerosol
operational system was moved from the National Weather Service mainframe computers
to the new NESDIS Central Environmental Satellite Computer System (CEMSCS)
mainframe computers.

January 8, 1993
It was discovered that some nighttime SST observations have been erroneously assigned
daytime type codes (i.e., 151) since the new navigation software was implemented in
October. A filter was put in to trap and discard these observations.

May 5, 1993
The time period for selection of observations to be transmitted over the World
Meteorological Organization (WMO) Global Telecommunications System (GTS) has
been changed from 24 to 15 hours. All observations during the previous 15 hours in a 2.5
degree latitude by 2.5 degree longitude box are averaged before transmission.
Previously, the nearest observation to the center of the box was transmitted (i.e., no
averaging).

May 25, 1993
A routine was added to the SST processing system to remove duplicate observations from
the SST 8-day observation file. In the past some duplicate observations were possible
when orbits would be reingested and reprocessed.

June 11, 1993




                                         E-32         NOAA POD Guide - Jan. 2002 Revision32
New SST equations were implemented for NOAA-11 SST to correct biases now that the
Pinatubo aerosols have dissipated. The MCSST split-window equation was erroneously
used as the daytime operational equation. The nighttime operational equation is the
NLSST triple window equation. The equations are:
NLSST DAY SPLIT
SST=0.92323(T11)+0.082523(Tsfc)(T11-T12)+0.463038(SEC sza-1)(T11-T12)-250.109

MCSST DAY SPLIT
SST=0.979224(T11)+2.361743(T11-T12)+0.33084(SEC sza-1)(T11-T12)-267.029

NLSST NIGHT TRIPLE
SST=0.970625(T11)+0.035216(Tsfc)(T3.7-T12)+1.522429(SEC sza-1)-263.231

NLSST NIGHT DUAL
SST=1.01876(T11)+.053929(Tsfc)(T3.7-T11)+1.830512(SEC sza-1)-276.439

NLSST NIGHT SPLIT
SST=0.899907(T11)+.091549(Tsfc)(T11-T12)+0.647912(T11-T12)(SEC sza-1)-243.821

MCSST NIGHT SPLIT
SST=0.978971(T11)+2.593454(T11-T12)+0.623203(T11-T12)(SEC sza-1)-267.542

June 14, 1993
Corrected daytime operational SST equation to the NLSST SPLIT WINDOW shown
under the June 11 entry above.

August 9, 1993
NOAA-I was launched at 10Z aboard an Atlas E launch vehicle from Vandenberg Air
Force Base.

August 21, 1993
Contact with NOAA-I (i.e., NOAA-13) was lost at about 18Z. A short -circuit caused by
a screw that was too long was the probable cause of failure.

October 7, 1993
Changed the radiation budget coefficients ACOF, BCOF, CCOF for NOAA-12.
Previously these had been old NOAA-10 coefficients. They have now been changed to
current NOAA-11 coefficients (see the July 2, 1990 entry for the coefficients).

October 11, 1993
Began outgassing of NOAA-12 in order to reduce the noise in the 3.7 micrometer
channel of the AVHRR. Radiation budget products will not be available during the
outage.

October 20, 1993
Completed the outgassing of NOAA-12.



                                       E-33        NOAA POD Guide - Jan. 2002 Revision33
December 1, 1993
Modifications were made to the calibration software in the AVHRR 1b processing to
correct for the effects of scattered sunlight in the 3.7 micrometer channel. This is the
same correction that was implemented in the SST processing program on November 9,
1992. Now the benefits of this correction have been made available to all AVHRR 1b
users.

December 20, 1993
Turned on the high-resolution land/sea tags in the NOAA-11 nighttime SST algorithm in
order to increase the number of retrievals in the Great Lakes. Previously, only the
daytime algorithm used the high-resolution land/sea tags in coastal regions. Use of high-
resolution land/sea tags allows SST observations to be made as close as 5 km to a land
boundary. Without the high-resolution tags, observations cannot be made any closer than
25 km to land.

May 4, 1994
A VS FORTRAN version of the SST field analysis program FLDGEN was implemented
for the 100, 50, and 14 km SST fields.

September 1, 1994
Changed the radiation budget operation to the NOAA-K,L,M retrieval system (i.e.,
RADRET).

September 7, 1994
Navigation change to HIRS processing. Navigation parameters are updated orbit by orbit
rather than once per day.

September 14, 1994
At approximately 00Z, NOAA-11 experienced an apparent electrical problem with the
AVHRR instrument. Other NOAA-11 instruments are now affected. No NOAA-11 SST
observations, radiation budget observations or aerosol observations were made after this
failure.

September 15, 1994
Began using NOAA-12 operationally for SST observation production.
The operational SST equations are the NLSST DAY SPLIT for daytime data and the
NLSST NIGHT TRIPLE for nighttime data (the other equations given are used in various
cloud tests). The equations being used were first derived on 3/8/94. The equations for
NOAA-12 are:

NLSST DAY SPLIT
SST=0.876992(T11)+0.083132(Tsfc)(T11-T12)+0.349877(SEC sza-1)(T11-T12)-
236.667

MCSST DAY SPLIT



                                         E-34         NOAA POD Guide - Jan. 2002 Revision34
SST=0.963563(T11)+2.579211(T11-T12)+0.242598(SEC sza-1)(T11-T12)-263.006

NLSST NIGHT TRIPLE
SST=0.963368(T11)+0.033139(Tsfc)(T3.7-T12)+ 1.731971(SEC sza-1)-260.854
NLSST NIGHT DUAL
SST=1.021468(T11)+.050549(Tsfc)(T3.7-T11)+2.201377(SEC sza-1)-276.9

NLSST NIGHT SPLIT
SST=0.888706(T11)+.081646(Tsfc)(T11-T12)+ 0.576136(T11-T12)(SEC sza-1)-
240.229

MCSST NIGHT SPLIT
SST=0.967077(T11)+2.384376(T11-T12)+0.480788(T11-T12)(SEC sza-1)-263.94

The following equations are not used in the SST operation, but are provided here for
reference:

MCSST NIGHT TRIPLE
SST=1.000281(T11)+0.911173(T3.7-T12)+1.710028(SEC sza-1)-271.971

MCSST NIGHT DUAL
SST=1.031355(T11)+1.288548(T3.7-T11)+2.265075(SEC sza-1)-279.846

September 20, 1994
Changed ACOF, BCOF and CCOF in the NOAA-12 RADRET radiation budget
coefficient database to what they should have been on September 1. They now
correspond to what was being used for NOAA-12 in the old radiation budget system.
The values are:

                                 ACOF                     BCOF                     CCOF
         OLD                      4.092                   1.1904                 -0.001025
         NEW                     -10.14                   1.2681                 -0.001117

CCOF, however, was not changed until October 3, 1994. It remained
-0.001012 until then.

September 21, 1994
Changed the ACONST and BCONST parameters in the RADRET coefficient data base.
The values are:

                                            ACONST                           BCONST
             OLD                            8961.325                         1308.647
             NEW                            6988.885                         1204.577




                                          E-35         NOAA POD Guide - Jan. 2002 Revision35
where ACONST=1.1910659 X 10-5 (v3) and BCONST=1.438833 (v), where v = central
wave number for the 12 micrometer channel (837.19 was used for the central wave
number).

October 3, 1994
Changed CCOF in the radiation budget system to -0.001117. Also in the radiation budget
system, changed the 11 and 12 micrometer channel central wave numbers and the 3.7
micrometer channel filter solar constant to the NOAA-12 values. These values have been
the NOAA-10 values. This appears at the first look to have brought NOAA-12 radiation
budget values down by approximately 20 W/m2, as hoped.

November 1, 1994
Changed the input parameters to the WMO satellite observation generation program to
the NOAA-12 satellite ID so that NOAA-12 observations go out to WMO users. This
product has been off-line since the NOAA-11 AVHRR failed on September 13, 1994.

November 15, 1994
The navigation system for the AVHRR 1b processing was updated to include clock
corrections (but this was not activated at this time). Navigation parameters in the header
are now scaled integers (easier to read).

December 30, 1994
NOAA-J was launched at 10:02Z aboard an Atlas-E launch vehicle, from Vandenberg
Air Force Base, California.

March 20, 1995
Began using NOAA-14 for operational processing of SST.
MCSST=linear multi-channel Sea Surface Temperature algorithm.
NLSST=Non-linear Sea Surface Temperature algorithm (SST). All equations based on
March 1995 global drifting buoy and tropical Pacific fixed buoy matchups. T3.7, T11
and T12 =AVHRR channels 3, 4 and 5 brightness temperatures (K). SEC0=secant of
Satellite zenith angle. Tsfc is an a priori estimate of surface temperature (degree C).
Preferably, it should be based on satellite only or blended or climatological based field
analysis but may be derived from the actual satellite measurements using one of the
MCSST equations. In operational use, Tsfc is limited to the range between 28 and -2
degrees C. The new day and night operational equations are denoted by asterix.

Example of use:
Night NLSST Split SST = 0.0781 x Tsfc x (T11-T12) + 0.9331 x T11
       +0.7381*(T11-T12) x (SEC0-1) -253.43 ( degrees C).

                          Regression Output: Night NLSST Split
                   Constant                                 -253.428
               Std Err of Y Est                             0.480436
                  R Squared                                 0.993766
              No. of Observations                              1055


                                          E-36         NOAA POD Guide - Jan. 2002 Revision36
             Degrees of Freedom                                 1051
                          Tsfc x (T11-T12)         T11            (T11-T12) x (SEC0-1)
   X Coefficient(s)           0.078095          0.933109                0.738128
   Std Err of Coef.           0.001017          0.004392                 0.03915

                          Regression Output: Night MCSST Split
                   Constant                                  -282.24
               Std Err of Y Est                             0.535959
                  R Squared                                 0.992242
             No. of Observations                               1055
             Degrees of Freedom                                1051
                              (T11-T12)              T11         (T11-T12) x (SEC0-1)
   X Coefficient(s)            2.275385           1.029088             0.752567
   Std Err of Coef.            0.033812           0.004022             0.043759

                      Regression Output: ***Night NLSST Triple***
                   Constant                                 -266.186
               Std Err of Y Est                             0.427116
                  R Squared                                 0.995073
             No. of Observations                              1055
             Degrees of Freedom                               1051
                          Tsfc x (T3.7-T12)           T11                  SEC0-1
   X Coefficient(s)           0.031889             0.980064               1.817861
   Std Err of Coef.           0.000316             0.003461               0.069577

                      Regression Output: Night MCSST Triple
                Constant                                -275.364
            Std Err of Y Est                             0.41102
               R Squared                                0.995438
          No. of Observations                              1055
          Degrees of Freedom                               1051
                          (T3.7-T12)              T11                  SEC0-1
X Coefficient(s)           0.920822            1.010037               1.730411
Std Err of Coef.           0.008757            0.003153               0.067026

                          Regression Output: Night NLSST Dual
                   Constant                                -276.813
               Std Err of Y Est                            0.461235
                  R Squared                                0.994255
             No. of Observations                              1055
             Degrees of Freedom                               1051
                          Tsfc x (T3.7-T11)          T11                   SEC0-1
   X Coefficient(s)           0.050086            1.019182                2.039266
   Std Err of Coef.           0.000541            0.003496                0.074861


                                     E-37      NOAA POD Guide - Jan. 2002 Revision37
                          Regression Output: Night MCSST Dual
                   Constant                                 -273.914
               Std Err of Y Est                             0.432718
                  R Squared                                 0.994943
             No. of Observations                              1055
             Degrees of Freedom                               1051
                             (T3.7-T11)               T11                        SEC0-1
   X Coefficient(s)           1.409936             1.008751                     1.975581
   Std Err of Coef.             0.01419            0.003332                     0.070296

                      Regression Output: *** Day NLSST Split ***
                   Constant                                 -255.165
               Std Err of Y Est                             0.507031
                  R Squared                                 0.994647
             No. of Observations                               865
             Degrees of Freedom                                861
                           Tsfc x (T11-T12)         T11          (T11-T12) x SEC0-1
   X Coefficient(s)            0.076066          0.939813             0.801458
   Std Err of Coef.             0.00148          0.004885             0.048744

                           Regression Output: Day MCSST Split
                   Constant                                  -278.43
               Std Err of Y Est                             0.570485
                  R Squared                                 0.993223
             No. of Observations                               865
             Degrees of Freedom                                861
                              (T11-T12)              T11         (T11-T12) x SEC0-1
   X Coefficient(s)            2.139588           1.017342            0.779706
   Std Err of Coef.            0.049017           0.004365            0.055699

March 28, 1996
The orbit vectors received from the U.S. Navy contained an apparent 1 second error for
all satellites. The error was not detected and corrected for NOAA-12 until after the
following passes were processed. All other satellites were not updated with the erroneous
orbit data. The navigation QC for NOAA-12 indicated an average error of 7.0 kilometers
at nadir. A list of all passes affected is provided below. The one second error has been
removed from the Navy vectors, however the quality of the orbital data is still somewhat
degraded. Navy personnel are investigating. Until this problem is resolved, Air Force
vectors will be used instead of the Navy vectors whenever possible.
NSS.GHRR.ND.D96088.S0109.E0257.B2529394.GC
NSS.GHRR.ND.D96088.S0615.E0809.B2529697.WI
NSS.GHRR.ND.D96088.S0804.E0958.B2529798.WI
NSS.GHRR.ND.D96088.S0953.E1144.B2529899.WI
NSS.GHRR.ND.D96088.S1140.E1325.B2529900.WI


                                        E-38         NOAA POD Guide - Jan. 2002 Revision38
NSS.GHRR.ND.D96088.S1320.E1500.B2530001.GC

NSS.HRPT.ND.D96088.S0259.E0310.B2529494.GC
NSS.HRPT.ND.D96088.S1327.E1336.B2530000.WI
NSS.HRPT.ND.D96088.S1504.E1509.B2530101.GC

NSS.LHRR.ND.D96088.S0206.E0213.B2529393.GC
NSS.LHRR.ND.D96088.S0210.E0221.B2529393.GC
NSS.LHRR.ND.D96088.S0505.E0513.B2529595.WI
NSS.LHRR.ND.D96088.S0635.E0646.B2529696.WI
NSS.LHRR.ND.D96088.S0755.E0804.B2529797.WI
NSS.LHRR.ND.D96088.S0814.E0825.B2529797.WI
NSS.LHRR.ND.D96088.S0855.E0906.B2529797.WI
NSS.LHRR.ND.D96088.S1220.E1231.B2529999.WI
NSS.LHRR.ND.D96088.S1312.E1323.B2530000.WI
NSS.LHRR.ND.D96088.S1320.E1331.B2530000.GC

April 18, 2000
On Friday April 14, 2000, it was discovered that NOAA-11 HIRS instrument was
experiencing a filter wheel motor anomaly. This caused an interruption in the HIRS
Level 1b data. Since that time the instrument team and SOCC have been trying to correct
the problem. Today the NOAA-11 HIRS filter wheel motor was set to high mode, and
the filter housing heater was turned on. These commands were nominal. Other
spacecraft telemetry remain nominal, as the instrument team continues to analyze the
HIRS filter wheel anomaly.

After numerous commands and attempts to restore the instrument to an operational state
have failed, the outlook for resuming operations is not very promising. The instrument
team along with members of NASA , and NESDIS operations personnel are currently
evaluating the situation and a decision to shut-off the instrument or not is pending.

This situation has caused the NOAA-11 Level 1b data to be unavailable, and future
availability is very bleak.

26 May 2000Beginning sometime after May 19th, we noticed that the earth location error
seen in the NOAA-14 AVHRR data is consistently about 1 to 2 kilometers. The current
clock drift error reported in the TBUS bulletin and on the Navigation home page
(http://www.osdpd.noaa.gov/PSB/PPP/NAVIGATION/navpage.html) has not changed
and if used with the current data will increase the error. We are observing the Level 1b
data to determine if this is a consistent change and to get some idea of why it has
occurred. Data for the other NOAA satellites have not changed. If our continued
investigation next week indicates that the clock drift data should be updated, the
Navigation website will be updated.

June 1, 2000




                                        E-39         NOAA POD Guide - Jan. 2002 Revision39
The clock drift reported for NOAA-14 still does not fit the data. It appears to also have a
+500 millisecond error that is negating the clock error.

June 20, 2000
In an effort to improve the ability to update and manage clock adjustments, SOCC has
updated the flight software on NOAA-14 and will be conducting a test of their clock
adjustment capability around 12:00 local today. The test is planned to begin on orbit
28209 from Gilmore around 1553Z. During this test time period, clock adjustments will
be made every 45 seconds in the following sequence.
+ 100 milliseconds (ms)
- 100 ms
+900 ms
- 900 ms
+ 750 ms
- 750 ms
+ 250 ms
- 250 ms
At the end of the test, data should have returned to the pre-test condition.

July 27, 2000
For NOAA -12 and -14, we are preparing our parallel operations to provide test data with
clock corrections turned on. These test files will also contain the corrected scan angle in
the AVHRR (we changed the maximum angle from 55.40 to 55.37). Our tests have
shown that as much as a 2 kilometer improvement will be seen in the earth locations from
the scan angle adjustment alone. The clock corrections will improve the data such that the
remaining error is approaching 1 kilometer or less.

We look forward to beginning the parallel tests for NOAA-12 and -14 next week and
turning on the corrections within two weeks of that date. The actual implementation data
will be announced next week.

August 15, 2000
On August 29, 2000, we plan to turn on clock corrections for all instrument level 1B data
processed for the NOAA-12 and 14 satellites. Turning on clock corrections should not
require a change by the user community. However, you should see an improvement in the
earth location data of approximately 6 kilometers for NOAA-D/12 and approximately a 2
kilometer improvement for NOAA-14 (both along track).

We also plan to implement the latest AELDS (Advanced Earth Location Data System) in
the NOAA-A-J SBUV processing. This change will alter the solar azimuth angle
computed so that sign of the value is switched (the magnitude remains the same).

29 Aug 2000
The updates to the NOAA A-J series processor became operational as indicated below.
This update included: turning on the clock drift updates, changing AVHRR max scan




                                         E-40          NOAA POD Guide - Jan. 2002 Revision40
angle to 55.37 rather than 55.40, and integration of updated earth location (AELDS)
into SBUV processing.

Please note that in the future the clock drift corrections will be turned on/off or adjusted
as dictated by the accuracy of the data and the adjustments applied by SOCC. The user
will be notified as soon as possible after the fact when problems occur. Please remember
to check the appropriate bits to know when corrections are being applied and the
magnitude of the corrections. There are scheduled clock updates for both NOAA-12 and
-14 today at 235900Z. The Level 1b data should automatically reflect the adjustments so
that the accuracy of the earth location data is maintained. No action is required on the
part of the Level 1b user. The planned updates are (as reported by SOCC):

NOAA-12's Elapsed Time Clock (ETC) is drifting negative at about 4 milliseconds per
day, and is now reading -1100 milliseconds. It is necessary to add 1.0 second to ETC to
bring it within the limit. This update is scheduled for August 29, 2000 via SCT at
23:59:00Z.

NOAA-14's ETC is drifting positive at about 8 milliseconds per day, and is now reading
+400 milliseconds. It is necessary to subtract 1.0 seconds from ETC to bring it within the
limit. This update is scheduled for August 29, 2000 via SCT at 23:59:00Z.

Last passes processed before change:
NSS.GHRR.ND.D00242.S0805.E0956.B4826465.WI
NSS.LHRR.ND.D00242.S1125.E1130.B4826666.WI
NSS.HRPT.ND.D00242.S1320.E1333.B4826767.MO
NSS.HRPT.NJ.D00242.S1227.E1241.B2919595.MO
NSS.LHRR.NJ.D00242.S1159.E1207.B2919595.GC
NSS.GHRR.NJ.D00242.S1038.E1219.B2919495.GC

Passes that may be lost, may be received late and processed after change:
NSS.GHRR.ND.D00242.D0951.E1137.B4826566.WI

First passes processed after change:
NOAA-14
NSS.HRPT.NJ.D00242.S1402.E1414.B2919696.GC
NSS.HRPT.NJ.D00242.S1409.E1419.B2919696.MO
NSS.GHRR.NJ.D00242.S1214.E1400.B2919596.GC
NSS.LHRR.NJ.D00242.S1344.E1356.B2919696.GC
NSS.LHRR.NJ.D00242.S1333.E1345.B2919596.GC

NOAA-12
NSS.HRPT.ND.D00242.S1454.E1505.B4826868.GC
NSS.LHRR.ND.D00242.S1209.E1219.B4826666.GC
NSS.LHRR.ND.D00242.S1306.E1311.B4826767.GC
NSS.TIPX.ND.D00242.S1131.E1325.B4826667.GC




                                          E-41         NOAA POD Guide - Jan. 2002 Revision41
SBUV NOAA-11
NSS.TIPS.NH.D00242.S1147.E1342.B6151718.WI

November 30, 2000NOAA A-J Level 1b preprocessing systems will be updated to allow
scan geometry parameters to be changed to user supplied parameters. This will give us
the ability to adjust the scan geometry differently for different satellites. User impact -
improved earth location data due to use of double precision variables. New MSU scan
angle 47.3685 degrees (difference in latitude of 0.01 degrees, longitude 0.03 degrees);
AVHRR new stepping angle 0.05407226563 degrees for all satellites.

December 13, 2000The preprocessor release 2.7 will be implemented into operations on
December 14, 2000 between the hours 11:05 am and 12:15 pm local time. The following
will be put into operations:
New earth location software changes for all instruments which will support NOAA-12
and -14.The first pass after the update will
be:NSS.GHRR.ND.D00249.S1420.E1544.B4979091.GCNSS.HRPT.NJ.D00349.S1633.
E1647.B3070808.GC

January 2, 2001
NOAA-12 and -14 Clock Corrections were discontinued after we discovered that the scan
line time codes were being changed incorrectly for all AVHRR Level 1b data. The
problem affected all AVHRR data for day 1 and 2 ending with the following passes:
NSS.GHRR.NJ.D01002.S1255.E1427.B3097475.GC
NSS.HRPT.NJ.D01002.S1428.E1441.B3097575.GC
NSS.LHRR.NJ.D01002.S1411.E1422.B3097575.GC

NSS.HRPT.ND.D01002.S1508.E1520.B5006161.GC
NSS.LHRR.ND.D01002.S1139.E1144.B5005959.GC

Clock corrections will be resumed as soon as a correction for the problem can be made.

The Computer Operations Branch has recreated the Level 1b files for those passes that
still had Level 1A data available on the CEMSCS. They will be automatically sent out
as normal. All instrument data was reprocessed and the following datasets were
reprocessed successfully:
NOAA-14
NSS.GHRR.NJ.D01002.S0357.E0552.B3096970.WI.A
NSS.GHRR.NJ.D01002.S0546.E0741.B3097071.WI.A
NSS.GHRR.NJ.D01002.S0736.E0929.B3097172.WI.A
NSS.GHRR.NJ.D01002.S0924.E1110.B3097273.WI.A
NSS.GHRR.NJ.D01002.S1106.E1259.B3097374.GC.A
NSS.GHRR.NJ.D01002.S1255.E1427.B3097475.GC.A
NSS.HRPT.NJ.D01002.S1249.E1257.B3097474.GC.A
NSS.HRPT.NJ.D01002.S1253.E1307.B3097474.MO.A
NSS.HRPT.NJ.D01002.S1428.E1441.B3097575.GC.A
NSS.LHRR.NJ.D01001.S2102.E2108.B3096565.GC.A



                                         E-42         NOAA POD Guide - Jan. 2002 Revision42
NSS.LHRR.NJ.D01001.S2247.E2251.B3096666.GC.A
NSS.LHRR.NJ.D01002.S0427.E0433.B3096969.WI.A
NSS.LHRR.NJ.D01002.S0904.E0915.B3097272.WI.A
NSS.LHRR.NJ.D01002.S1051.E1103.B3097373.WI.A
NSS.LHRR.NJ.D01002.S1411.E1422.B3097575.GC.A
NSS.TIPH.NJ.D01002.S1249.E1257.B3097474.GC.A
NSS.TIPH.NJ.D01002.S1253.E1308.B3097474.MO.A
NSS.TIPH.NJ.D01002.S1428.E1441.B3097575.GC.A
NSS.TIPX.NJ.D01002.S0357.E0552.B3096970.WI.A
NSS.TIPX.NJ.D01002.S0546.E0741.B3097071.WI.A
NSS.TIPX.NJ.D01002.S0736.E0929.B3097172.WI.A
NSS.TIPX.NJ.D01002.S0924.E1110.B3097273.WI.A
NSS.TIPX.NJ.D01002.S1106.E1259.B3097374.GC.A
NSS.TIPX.NJ.D01002.S1255.E1427.B3097475.GC.A

NOAA-12
NSS.HRPT.ND.D01002.S1329.E1338.B5006060.GC.A
NSS.HRPT.ND.D01002.S1334.E1348.B5006060.MO.A
NSS.HRPT.ND.D01002.S1334.E1348.B5006060.MO.A
NSS.LHRR.ND.D01001.S2057.E2105.B5005050.WI.A
NSS.LHRR.ND.D01001.S2114.E2120.B5005050.WI.A
NSS.LHRR.ND.D01002.S0140.E0145.B5005353.GC.A
NSS.LHRR.ND.D01002.S0239.E0247.B5005353.GC.A
NSS.LHRR.ND.D01002.S0958.E1003.B5005858.WI.A
NSS.LHRR.ND.D01002.S1139.E1144.B5005959.GC.A
NSS.TIPH.ND.D01002.S1329.E1338.B5006060.GC.A
NSS.TIPH.ND.D01002.S1334.E1348.B5006060.MO.A
NSS.TIPH.ND.D01002.S1508.E1520.B5006161.GC.A
NSS.TIPX.ND.D01002.S0448.E0643.B5005556.WI.A
NSS.TIPX.ND.D01002.S0638.E0832.B5005657.WI.A
NSS.TIPX.ND.D01002.S0827.E1011.B5005758.WI.A
NSS.TIPX.ND.D01002.S1005.E1200.B5005859.GC.A
NSS.TIPX.ND.D01002.S1156.E1326.B5005960.GC.A
NSS.TIPX.ND.D01002.S1322.E1507.B5006061.GC.A

January 19, 2001
On January 24,2001, clock drift corrections will be turned on for NOAA-12 and
NOAA-14.

January 24, 2001
Clock corrections for NOAA-12 and -14 were resumed today. It is easier to identify
those orbits processed today that do not have clock error corrections included. The
following orbits were the last passes processed before clock corrections went into effect.

For NOAA-14 GHRR (also for TIPX):
NSS.GHRR.NJ.D01024.S0122.E0301.B3127879.GC



                                         E-43         NOAA POD Guide - Jan. 2002 Revision43
NSS.GHRR.NJ.D01024.S0255.E0450.B3127980.WI
NSS.GHRR.NJ.D01024.S0444.E0639.B3128081.WI
NSS.GHRR.NJ.D01024.S0634.E0828.B3128182.WI
NSS.GHRR.NJ.D01024.S1014.E1207.B3128384.GC
NSS.GHRR.NJ.D01024.S1203.E1327.B3128485.GC

The last passes processed before clock corrections were turned on for HRPT were:
NSS.HRPT.NJ.D01024.S1329.E1341.B3128585.GC
NSS.HRPT.ND.D01024.S1328.E1341.B5037373.MO

The last pass processed before clock corrections were turned on for NOAA-12 TIPX was:
NSS.TIPX.ND.D01024.S0829.E1004.B5037071.WI

The only passes processed for day 024 with no clock corrections for LHRR were:
NSS.LHRR.NJ.D01024.S0146.E0152.B3127878.GC
NSS.LHRR.NJ.D01024.S0441.E0449.B3128080.WI
NSS.LHRR.ND.D01024.S0030.E0036.B5036565.GC

February 21, 2001
Beginning with the following passes, the Level 1b pre-processor for NOAA-12 and -14
was updated. This should have been a no impact change to the earth location portion of
the software.

NOAA-12
NSS.GHRR.ND.D01052.S1729.E1925.B5077475.WI

NOAA-14
NSS.GHRR.NJ.D01052.S1755.E1950.B3168384.WI

E.2               CHANGES MADE TO NAVY SST OBSERVATION
              PRODUCT

March 30, 1995
Began using NOAA-14 for operational processing of SST=s. All equations based on
February and March 1995 global drifting buoy match ups. The operational SST equations
are the NLSST DAY SPLIT for daytime data and the NLSST NIGHT TRIPLE for
nighttime data.

NLSST DAY SPLIT
NL(4/5) = .9355T4 + .0780Tf (T4-T5) + .8009 (T4-T5)(SEC(A) -1) - 254.0163

NLSST NIGHT TRIPLE
NL(3/4/5) = .9796T4 + .032Tf (T3-T5) + 1.8106 (SEC (A) -1) - 266.1146

T3 = Channel 3 Brightness Temperature (K)
T4 = Channel 4 Brightness Temperature (K)



                                        E-44        NOAA POD Guide - Jan. 2002 Revision44
T5 = Channel 5 Brightness Temperature (K)
Tf = Analyzed Field Temperature (C)
A = Satellite Zenith Angle

April 11, 1995
Began operationally storing satellite retrievals up to 80N latitude within the TOGA and
daily 100 km field file as well as matching satellite retrievals and buoy measurements
within the satellite match up database.

May 18, 1995
Operationally implemented HIRS two part cloud screening test for relaxed daytime
processing, replacing current relaxed visible cloud threshold test. This change was
necessary due to the occurrence of high Channel 2 reflectance in sun glitter ocean areas.
In order to produce retrievals in sun glitter ocean areas the daytime gross Channel 2 cloud
test was relaxed from 10 to 50 percent reflectance.

June 7, 1995
The moored TOGA-TAO array buoys have been placed into the SST Match up data base.
This data source is now used for statistical accuracy comparisons in addition to the
present drifting buoy data.

June 14, 1995
Limited relaxed daytime processing to latitude bands where sun glitter is frequent (60N-
60S), also reduced gross Channel 2 threshold from 50 to 15 percent since most relaxed
daytime retrievals obtained in sun glitter regions were less than 15 percent reflectance.
These modifications were implemented to eliminate the generation of relaxed daytime
retrievals over ice.

June 16, 1995
Modified threshold for the 100 km field portion of the HIRS two part cloud screening test
for relaxed daytime processing from 3.0 to 2.5 to be more restrictive.

June 22, 1995
Improved and expanded coverage of NOAA-14 visible cloud threshold table, with the
addition of 200+ orbits of reflectance data collected during the month of May.

October 23, 1995
NOAA-14 Channel 2 calibration was corrected by NOAA/NESDIS operations on July
31. A new visible cloud threshold table was generated using 250+ orbits of Channel 2
reflectance data obtained during the August time frame and operationally implemented.

October 24, 1995
Modified relaxed daytime cloud screening, the HIRS two part test is only utilized
between 40N-40S with high latitude regions using the previous retrieval method of
relaxing the visible cloud threshold table by a relaxation factor of approximately 1.5.




                                          E-45         NOAA POD Guide - Jan. 2002 Revision45
November 20, 1995
The latitudinal band for the relaxed daytime HIRS two part test was modified to be
between 40N-50S to allow for seasonal shift in the sun glitter pattern.

December 7, 1995
Operationally implemented new coefficients for the HIRS portion of the HIRS two part
test for NOAA-14.

May 30, 1996
The latitudinal band for the relaxed daytime HIRS two part test was modified to be
between 50N-50S, due to the withdrawal of the ice edge in the northern hemisphere.

November 4, 1996
After a successful completion of OPTEST, operational processing of satellite SST
retrievals was moved from Concurrent mainframes to SGI challenge workstations.

November 25, 1996
The latitudinal band for the relaxed daytime HIRS two part test was modified to be
between 40N-50S to account for the southward drift of the northern hemisphere ice edge.

January 29, 1997
Modified Channel 2 nighttime reflectance test. Increased Channel 2 reflectance
threshold for twilight regions ( solar zenith angles between 75 - 90 ) from 1.0 to 1.7,
leaving the threshold at 1.0 for solar zenith angles greater than 90.

February 20, 1997
Modified Channel 2 nighttime reflectance test. Increased Channel 2 reflectance threshold
for twilight regions from 1.7 to 1.8. Modified Channels 4-5 threshold for nighttime
processing from 4.0 to 3.5.

March 20, 1997
Modified daytime gross Channel 2 cloud test from 15 to 18 percent reflectance. This
change was implemented to fill data voids occurring in high sun glint regions in the
Indian Ocean and Tropical Pacific.

April 17, 1997
Operationally implemented new visible cloud threshold table (obtained from
NOAA/NESDIS) consisting of data collected during the November 1996 - February 1997
time frame.

April 21, 1997
Expanded K100 land/sea tags in coastal areas. NLSSTs are now being calculated with
100 km field values as the Tf term rather than MCSST estimates, which have proven to
be occasionally cloud contaminated. The Two Part HIRS/FLD test and climatology test
are now fully functional in these areas since the 100 km field has a valid SST value and
climatology value along the coastal regions.



                                          E-46         NOAA POD Guide - Jan. 2002 Revision46
May 19,1997
The latitudinal band for the relaxed daytime Two Part HIRS/FLD test was modified to be
between 50N - 50S, due to withdrawal of the ice edge in the Northern Hemisphere.

August 6, 1997
Operationally implemented lower limit check (if Tf term is less than 0.1, set Tf term to
0.1) for 100 km field value used in NLSST calculations.

November 26, 1997
Operationally implemented a hybrid climatology file. This climatology file contains data
from NCEP adjusted Optimum Interpolation (OI) climatology from 70 S to 70 N and data
from NCAR 20 year climatology from 70 N to 80 N.

December 8, 1997
Modified operational 100 km file, initiating field and climatological values in the Great
Lakes.

December 8, 1997
The latitudinal band for the relaxed daytime HIRS two part test was modified to be
between 40 N - 50 S to account for the southward drift of the Northern Hemisphere ice
edge.

January 7, 1998
Modified cloud screening techniques in areas of high specular reflectance, relaxed
daytime processing will use the HIRS two part test only in high specular reflectance areas
and the relaxed visible cloud threshold test for all other portions of the scan. This results
in a reduction of aerosol contaminated retrievals.

March 31, 1998
The PIRATA (Pilot Research Moored Array in the Tropical Atlantic) array buoys have
been placed into the MCSST Matchup Database. This data source is now used for
operational MCSST statistical accuracy comparisons.

May 11, 1998
Began updating K100 climatology values on a daily basis versus monthly updates.

July 6, 1998
Operationally incorporated AOD (Aerosol Optical Depth) values into orbital MCSST
product.

October 5, 1998
Implemented new VCLD (Visible Cloud Threshold Table), modifying table default
values from 1.6% reflectance to 1.8%.

November 23, 1998



                                          E-47         NOAA POD Guide - Jan. 2002 Revision47
Modified daytime target high-density search pattern resulting in improved data
distribution.

December 9, 1998
Implemented new VCLD table (obtained from NOAA/NESDIS), this table was generated
to compensate for low daytime observations caused by new scan angle geometry.

March 31, 1999
NOAA-14: After a successful completion of OPTEST, operational processing of
MCSST's was moved from SGI Challenge workstations to SGI Origin 2000 workstations.

April 12, 1999
NOAA-14: Modified processing code to use calculated solar zenith angle for cloud
screening tests versus nearest angle extracted from input data set.

April 12, 1999
NOAA-14: Modified type 159 processing, HIRS/2 part test is run in all areas outside of
specular reflectance regions in addition to relaxed visible cloud test. Specular reflectance
regions do not run the relaxed visible cloud test.

May 18, 1999
Updated NOAA-14 equations based on March 1999 global drifting buoy match ups. The
operational MCSST equations are the NLSST DAY SPLIT and the NLSST NIGHT
TRIPLE.

NLSST DAY SPLIT
NL(4/5) = .9309T4 + .0768Tf (T4-T5) + .6612 (T4-T5)(SEC(A) -1) - 252.5215
NLSST NIGHT TRIPLE
NL(3/4/5) = .9807T4 + .032Tf (T3-T5) + 1.7326 (SEC (A) -1) - 266.3910

T3 = Channel 3 Brightness Temperature (K)
T4 = Channel 4 Brightness Temperature (K)
T5 = Channel 5 Brightness Temperature (K)
Tf = Analyzed Field Temperature (C)
A = Satellite Zenith Angle

August 17, 2000
NOAA-14: Modified nighttime cloud screening, replaced low stratus AVHRR 5-3 test
with AVHRR 4-3 test.

August 28, 2000
NOAA-14: Implemented new Visible Cloud Threshold table, generated with data
collected during the July-Aug, 2000 time frame.

October 10, 2000




                                          E-48         NOAA POD Guide - Jan. 2002 Revision48
NOAA-14: Updated NOAA-14 equations based on August 2000 global drifting buoy
matches. The operational MCSST equations are the NLSST DAY SPLIT and the NLSST
NIGHT TRIPLE.

NLSST DAY SPLIT
NL(4/5) = .9522T4 + .0755Tf (T4-T5) + .6723 (T4-T5)(SEC(A) B1) B 258.5574

NLSST NIGHT TRIPLE
NL(3/4/5) = .9810T4 + .0321Tf (T3-T5) + 1.8030 (SEC(A) B1) B 266.3967

T3 = Channel 3 Brightness Temperature (K)
T4 = Channel 4 Brightness Temperature (K)
T5 = Channel 5 Brightness Temperature (K)
Tf = Analyzed Field Temperature (C)
A = Satellite Zenith Angle

February 27, 2001
NOAA-14: Updated NOAA-14 nighttime equations based on January 2001 global
drifting buoy matches. The operational MCSST nighttime equation is the NLSST
NIGHT TRIPLE.

NLSST NIGHT TRIPLE
NL(3/4/5) = .9774T4 + .0334Tf (T3-T5) + 1.4792 (SEC(A) B1) B 264.9391

T3 = Channel 3 Brightness Temperature (K)
T4 = Channel 4 Brightness Temperature (K)
T5 = Channel 5 Brightness Temperature (K)
Tf = Analyzed Field Temperature (C)
A = Satellite Zenith Angle

March 7, 2001
Operationally implemented new orbital MCSST processing software (SEATEMP). The
new software contains improved cloud screening, which enables more retrieval attempts
per target for both day and night processing.

NOAA-14: Implemented Orbital MCSST equations derived for NOAA-14 SEATEMP
processing. Equations based on January 2001 global drifting buoy matches. The
operational MCSST equations are the NLSST DAY SPLIT and the NLSST NIGHT
TRIPLE.

NLSST DAY SPLIT
NL(4/5) = .9506T4 + .0760Tf (T4-T5) + .6839 (T4-T5)(SEC(A) B1) B 258.0968

NLSST NIGHT TRIPLE
NL(3/4/5) = .9843T4 + .0332Tf (T3-T5) + 1.4158 (SEC(A) B1) B 266.8967



                                       E-49         NOAA POD Guide - Jan. 2002 Revision49
T3 = Channel 3 Brightness Temperature (K)
T4 = Channel 4 Brightness Temperature (K)
T5 = Channel 5 Brightness Temperature (K)
Tf = Analyzed Field Temperature (C)
A = Satellite Zenith Angle

May 21, 2001
NOAA-14: Updated NOAA-14 nighttime equations based on April 2001 global drifting
buoy matches. The operational MCSST nighttime equation is the NLSST NIGHT
SPLIT.

NLSST NIGHT SPLIT
NL(4/5) = .9242T4 + .0755Tf (T4-T5) + .6040 (T4-T5)(SEC(A) B1) B 250.4284
T4 = Channel 4 Brightness Temperature (K)
T5 = Channel 5 Brightness Temperature (K)
Tf = Analyzed Field Temperature (C)
A = Satellite Zenith Angle

June 28, 2001
NOAA-14: Implemented a field test for type 159 processing in areas of high specular
reflectance. This test will help eliminate the generation of aerosol contaminated
observations.

September 18, 2001
NOAA-14: Implemented a two-part nighttime aerosol test. The test has to fail both an
SST intercomparison (MC(3/4) equation minus NL (4/5) equation) and a field test to be
rejected as aerosol contaminated.
October 9, 2001
NOAA-14: Implemented reliability values that are assigned to each MCSST observation.




                                       E-50        NOAA POD Guide - Jan. 2002 Revision50
APPENDIX F:            Using Brouwer-mean elements from TBUS Part IV

The Brouwer-mean elements in part IV of the APT predict bulletin (TBUS) can be used
in a stand-alone Brouwer-Lyddane orbit prediction package to determine orbit position
information at any time (t - t0) where t0 represents the time of the Brouwer mean elements
in part IV and t represents the user request time. The Brouwer-Lyddane algorithm is an
analytical solution of satellite motion for a simplified disturbing potential field limited to
zonal harmonic coefficients for J2 through J5. Lyddane modified Brouwer's formulation
to obtain algorithms applicable for zero eccentricity and zero inclination.

The Brouwer-Lyddane orbit prediction package contains seven subroutines and one block
data subprogram which can be called from a user supplied driver to obtain orbit
information in the form desired by the user.

The first subroutine to be called is BROLYD. This subroutine takes as input the Brouwer
mean or osculating elements at time t0, and outputs the osculating Keplerian and Brouwer
mean elements at the time (t - t0) given in common block BLCNST. The calling
sequence for subroutine BROLYD is described below.

If users require output in the form of inertial position and velocity vectors then a second
subroutine CELEM can be called. This subroutine takes as input the osculating
Keplerian elements for BROLYD and outputs the inertial position and velocity vectors.
The calling sequences for subroutine CELEM is also described below.

A third subroutine, BFIXED, transforms the position and velocity vectors from CELEM
to earth fixed coordinates. The user must supply the Greenwich hour angle to this
subroutine.

Subroutine XYZPLH converts the position vector in the earth fixed coordinates to
geodetic latitude, east longitude, and height.

Three other subroutines are included in this prediction package. These are DKEPLR,
MA3331, and DATAN0. DKEPLR is a subroutine to solve Kepler's equation. MA3331
computes the product of a 3 x 3 matrix and a 3 x 1 matrix. DATAN0 computes a value
for the arc-tangent between 0 and 2π.

A block data subprogram for the common block BLCNST includes several constants
needed by the stand-alone orbit prediction package. These constants are described below
and are presently used in NESDIS's polar navigation system.


CALLING SEQUENCE FOR SUBROUTINE BROLYD:

CALL BROLYD (OSCELE, DPELE, IPERT, IPASS, IDMEAN, ORBEL)

ARGUMENTS:

OSCELE - OUTPUT OSCULATING ELEMENTS AT TIME TTO


                                             F-1         NOAA POD Guide - Jan. 2002 Revision1
      OSCELE (1) = SEMI-MAJOR AXIS
      OSCELE (2) = ECCENTRICITY
      OSCELE (3) = INCLINATION
      OSCELE (4) = NODE
      OSCELE (5) = ARGUMENT OF PERIGEE
      OSCELE (6) = MEAN ANOMALY

DPELE -      INPUT IS OSCULATING ELEMENTS AT EPOCH IF IDMEAN = 0
             INPUT IS BROUWER MEAN AT EPOCH IF IDMEAN  0
             OUTPUT ELEMENTS ARE BROUWER MEAN AT TIME TTO

      DPELE (1) = SEMI-MAJOR AXIS
      DPELE (2) = ECCENTRICITY
      DPELE (3) = INCLINATION
      DPELE (4) = NODE
      DPELE (5) = ARGUMENT OF PERIGEE
      DPELE (6) = MEAN ANOMALY

IDMEAN - DETERMINES WHICH ELEMENTS ARE INPUT IN DPELE
   = 0, OSCULATING
    0, BROUWER MEAN

IPASS  =1, COMPUTE CONSTANTS NEEDED IN COMPUTATION OF OSCULATING
ELEMENTS
   =2, UPDATE OSCULATING ELEMENT TO OBSERVATION TIME WITHOUT
UPDATING CONSTANTS

IPERT =0, NO PERTURBATIONS DUE TO OBLATENESS COMPUTED
   =1, SECULAR TERMS COMPUTED
   =2, SECULAR + LONG PERIODIC + SHORT PERIODIC TERMS

ORBEL - OUTPUT AUXILIARY ORBITAL ELEMENTS

CALLING SEQUENCE FOR SUBROUTINE CELEM:

CALL CELEM (ORBEL, GMC, PV, VV)

ARGUMENTS:

ORBEL - INPUT OSCULATING ELEMENTS

      ORBEL (1) = SEMI-MAJOR AXIS

      ORBEL (2) = ECCENTRICITY

      ORBEL (3) = INCLINATION

      ORBEL (4) = NODE

      ORBEL (5) = ARGUMENT OF PERIGEE

      ORBEL (6) = MEAN ANOMALY

GMC - INPUT GRAVITATIONAL CONSTANT




                                        F-2    NOAA POD Guide - Jan. 2002 Revision2
PV - OUTPUT CARTESIAN POSITION VECTOR

       PV (1) = X

       PV (2) = Y

       PV (3) = Z

VV - OUTPUT CARTESIAN VELOCITY VECTOR

       VV (1) = XDOT

       VV (2) = YDOT

       VV (3) = ZDOT

COMMON BLOCK BLCNST

COMMON/BLCNST/TTO, R, AE, GM, BJ2, BJ3, BJ4, BJ5, FLTINV, XKE, ESQ

VARIABLES USED IN COMMON/BLCNST/:

TTO - INPUT REQUEST TIME IN SECONDS FROM EPOCH

R - OUTPUT MAGNITUDE OF SATELLITE RADIUS VECTOR

AE - INPUT MEAN EQUATORIAL RADIUS OF THE EARTH (KM)

GM - INPUT GRAVITATIONAL CONSTANT OF THE EARTH (KM3/SEC2)

BJ2 - INPUT C2, 0 ZONAL HARMONIC COEFFICIENT

BJ3 - INPUT C3, 0 ZONAL HARMONIC COEFFICIENT

BJ4 - INPUT C4, 0 ZONAL HARMONIC COEFFICIENT

BJ5 - INPUT C5 ,0 ZONAL HARMONIC COEFFICIENT

FLTINV - INPUT INVERSE FLATTENING COEFFICIENT (1/F)

XKE - GRAVITATIONAL CONSTANT (EARTH RADII)3/2/MIN)

ESQ - THE SQUARE OF THE MAJOR ECCENTRICITY CALCULATED FROM e 2=(2f - f 2)




                                         F-3        NOAA POD Guide - Jan. 2002 Revision3
C***********************************************************************************   00000010
C                                                                                      00000020
C NAME - AMMSMA                                                                        00000030
C LANGUAGE - FORTRAN TYPE - SUBROUTINE                                                 00000040
C VERSIONS - 1.0       DATE - 07/01/81 PROGRAMMER - T.LIU                              00000050
C                                                                                      00000060
C FUNCTIONS:                                                                           00000070
C        TO CALCULATE THE AVERAGE MEAN MOTION AND THE SEMIMAJOR                        00000080
C        AXIS.                                                                         00000090
C INPUT PARAMETERS:                                                                    00000100
C        COMMON/DATA2/........                                                         00000110
C OUTPUT PARAMETERS:                                                                   00000120
C        DMEAN - AVERAGE MEAN MOTION                                                   00000130
C        BMELMT(1) - SEMIMAJOR AXIS                                                    00000140
C                                                                                      00000150
C SUBROUTINES CALLED: NONE                                                             00000160
C***********************************************************************************
00000200
    SUBROUTINE AMMSMA(DMEAN,BMELMT)                                                    00000210
    IMPLICIT REAL*8 (A-H,O-Z)                                                          00000220
    COMMON/DATA2/ DESIGI,EPTIME,DMMDT,D2MDT,                                           00000230
   1 DRAGT,IETYPE,NELSET,DINCL,RASC,ECC,ARGP,DMEANA,                                   00000240
   2 DMMOT,IREVNO,ISATNO                                                               00000250
    REAL*8 BMELMT(6)                                                                   00000260
    COMMON/BLCNST/ TTO,R,AE,GM,BJ2,BJ3,BJ4,BJ5,FLTINV,XKE,ESQ                          00000261
    DATA TOTHRD,RE,DEGRAD/0.66666667,1.,0.01745329252D0/                               00000270
    DATA TWOPI/6.2831853/                                                              00000290
    DATA XMNPDA/1440./                                                                 00000295
    XJ2=-BJ2                                                                           00000299
    CK2=.5*XJ2*RE**2                                                                   00000300
   TEMP=TWOPI/XMNPDA/XMNPDA                                                            00000320
    DMEN=DMMOT*TEMP*XMNPDA                                                             00000350
    RINCL=DINCL*DEGRAD                                                                 00000400
    A1=(XKE/DMEN)**TOTHRD                                                              00000500
    COSIO=DCOS(RINCL)                                                                  00000600
   THETA2=COSIO*COSIO                                                                  00000700
    X3THM1=3.*THETA2-1.                                                                00000800
    EOSQ=ECC*ECC                                                                       00000900
    BETAO2=1.-EOSQ                                                                     00001000
    BETAO=DSQRT(BETAO2)                                                                00001100
    DEL1=1.5*CK2*X3THM1/(A1*A1*BETAO*BETAO2)                                           00001200
    AO=A1*(1.-DEL1*(.5*TOTHRD+DEL1*(1.+134./81.*DEL1)))                                00001300
    DELO=1.5*CK2*X3THM1/(AO*AO*BETAO*BETAO2)                                           00001400
    DMEAN=DMEN/(1.+DELO)                                                               00001500
    DSEMI=AO/(1.-DELO)                                                                 00001600
    BMELMT(1)=DSEMI*AE                                                                 00001650
    RETURN                                                                             00001700
    END                                                                                00000018




                                         F-4        NOAA POD Guide - Jan. 2002 Revision4
            SUBROUTINE BFIXED(KEY,GHA,PV,VV,POSOUT,VELOUT,B) IMPLICIT REAL*8 (A-H, O-Z)
C****************************************************************C
C      NAME - BFIXED
C
C      LANGUAGE- FORTHXP TYPE- SUBROUTINE
C
C      VERSION- 1.0 DATE- 10/14/77          PROGRAMMER- SACHS, A.
C
C      PURPOSE -TRANSFORM THE POSITION AND VELOCITY FROM TIME OF DAY TO
C      PSEUDO BODY FIXED.
C
C      INPUT PARAMETERS - KEY= 3 FOR RETURN OF BODY FIXED POSITION
C      ONLY, GHA= GREENWICH HOUR ANGLE IN RADIANS, PV= POSITION VECTOR,
C      VV= VELOCITY VECTOR (KM/SEC).
C
C      OUTPUT PARAMETERS - POSOUT =POSITION VECTOR, VELOUT =VELOCITY
C      VECTOR, B =ROTATION MATRIX.
C
C      SUBROUTINES CALLED - MA3331
C
C      COMMENT- B MATRIX COMPUTATION IS FROM SUBROUTINE EVAL OF GTDS.
C
C****************************************************************C
C
       DIMENSION B(3,3), BDOT(3,3), PV(3), VV(3), VELOUT(3), VOUT(3)
       DIMENSION POSOUT(3)
       DATA OMEGAE, BDOT/7.29211585494D-5, 9*0.D0/
C COMPUTE MATRIX TO ROTATE POSITION FROM TOD TO PSUEDO BODY FIXED.
C SPIN FACTOR IS ZERO.
       XP=0.0D0
       YP=0.0D0
       B(1,1) = DCOS(GHA)
       B(1,2) = DSIN(GHA)
       B(1,3) = XP
       B(2,1) = -B(1,2)
       B(2,2) = B(1,1)
       B(2,3) = -YP
       B(3,1) = -XP*B(1,1)-YP*B(1,2)
       B(3,2) = -XP*B(1,2)+YP*B(1,1)
       B(3,3) = 1.0D0
C ROTATE THE INPUT POSITION VECTOR.
       CALL MA3331 (B,PV.POSOUT)
       IF (KEY.EQ.3) GO TO 30
C COMPUTE MATRIX TO ROTATE VELOCITY FROM TOD TO PSUEDO BODY FIXED.
       BDOT(1,1) = -B(1,2)
       BDOT(1,2) = B(1,1)
       BDOT(2,1) = -B(1,1)
       BDOT(2,2) = -B(1,2)
C ROTATE THE INPUT VELOCITY VECTOR.
       CALL MA3331(B,VV,VOUT)
C ROTATE THE INPUT POSITION VECTOR.
       CALL MA3331(BDOT,PV,VELOUT)
C OBTAIN THE BODY FIXED VELOCITY.
       DO 20 I=1,3
    20 VELOUT(I) = VELOUT(I)*OMEGAE + VOUT(I)



                                      F-5        NOAA POD Guide - Jan. 2002 Revision5
30 CONTINUE
    RETURN
    END




              F-6   NOAA POD Guide - Jan. 2002 Revision6
       BLOCK DATA
       IMPLICIT REAL*8 (A-H,O-Z)
C*************************************************************************************
*****                                                                                      C
C      NAME- BLCNST
C
C      LANGUAGE- FORTHXP              TYPE- PROGRAM
C
C      THIS COMMON BLOCK WAS UPDATED MARCH 28, 1984 TO INCLUDE XKE
C      AND ESQ BY E. HARROD S/SP12
C      THIS BLOCK DATA IS COMPILED WITH THE ROUTINE PSCEAR, ANY
C      PROGRAM USING PSCEAR DOES NOT NEED TO RECOMPILE THIS BLOCK
C      DATA
C
C*************************************************************************************
*****                                                                                      C
       COMMON/BLCNST/ TTO,R,AE,GM,BJ2,BJ3,BJ4,BJ5,FLTINV,XKE,ESQ
       DATA TTO,R,GM,AE,BJ2,BJ3,BJ4,BJ5,FLTINV,XKE,ESQ/2*0.D0,
      1 398600.8D0,6378.135D0,-0.10826158D-02,0.25388100D-05,
      2 0.16559700D-05,0.21848266D-06,298.25D0,0.743669161D-01,
      3 0.6994317778266721D-02/
       END




                                         F-7        NOAA POD Guide - Jan. 2002 Revision7
         SUBROUTINE BROLYD(OSCELE,DPELE,IPERT,IPASS,IDMEAN,ORBEL)
C*************************************************************************************
******
C*       REF. "BROUWER-LYDDANE ORBIT GENERATOR ROUTINE"                                                                             *
C*                             (X-553-70-223)                                                                                       *
C*                  BY E.A. GALBREATH 1970                                                                                          *
C*----------------------------------------------------------------------------------------------------------------------------- -
--------                                                                                                                            *
C*       MODIFIED 7/31/74 VIONA BROWN AND R.A. GORDON TO INTERFACE                                                                  *
C*       WITH GTDS                                                                                                                  *
C*************************************************************************************
*******
         IMPLICIT REAL*8(A-H,O-Z)
         REAL*8 PI2/6.283185307179586D0/
         DIMENSION OSCELE(6), DPELE(6), ORBEL(5)
         COMMON /BLCNST/ TTO,R,AE,GM,BJ2,BJ3,BJ4,BJ5,FLTINV,XKE,ESQ
         DATA BMU,RE/1.0D0,1.0D0/,BKSUBC/0.01D0/
         EK = DSQRT(GM/AE**3)
         DELT = EK*TTO
         GO TO (10,111), IPASS
C
C EPOCH ELEMENTS AT EPOCH TIME
C
     10 ADP = DPELE(1)/AE
         EDP = DPELE(2)
         BIDP = DPELE(3)
         HDP = DPELE(4)
         GDP = DPELE(5)
         BLDP = DPELE(6)
         A0 = ADP
         E0 = EDP
         BI0 = BIDP
         H0 = HDP
         G0 = GDP
         BL0 = BLDP
         IFLG = 0
C
C COMPUTE MEAN MOTION
C
         ANU=DSQRT(BMU/A0**3)
C
C COMPUTE FRACTIONS
C
         F3D8=3.0D0/8.0D0
         F1D2=1.0D0/2.0D0
         F3D2=3.0D0/2.0D0
         F1D4=1.0D0/4.0D0
         F5D4=5.0D0/4.0D0
         F1D8=1.0D0/8.0D0
         F5D12=5.0D0/12.0D0
         F1D16=1.0D0/16.0D0
         F15D16=15.0D0/16.0D0
         F5D24=5.0D0/24.0D0
         F3D32=3.0D0/32.0D0
         F15D32=15.0D0/32.0D0
         F5D64=5.0D0/64.0D0



                                                              F-8             NOAA POD Guide - Jan. 2002 Revision8
       F35384=35.0D0/384.0D0
       F35576=35.ODO/576.0D0
       F35D52=35.0D0/1152.0D0
       F1D3=1.0D0/3.0D0
       F5D16=5.0D0/16.0D0
       BK2 = -F1D2*(BJ2*RE*RE)
       BK3 = BJ3*RE**3
       BK4 = F3D8*(BJ4*RE**4)
       BK5=BJ5*RE**5
       GO TO 153
   111 IF(IPERT.EQ.0)GO TO 7
       IF(IDMEAN.NE.0)GO TO 202
       ADP = DPELE(1)/AE
       EDP = DPELE(2)
       BIDP = DPELE(3)
       HDP = DPELE(4)
       GDP = DPELE(5)
       BLDP = DPELE(6)
   153 EDP2=EDP*EDP
       CN2=1.0-EDP2
       CN=DSQRT(CN2)
       GM2=BK2/ADP**2
       GMP2=GM2/(CN2*CN2)
       GM4=BK4/ADP**4
       GMP4=GM4/CN**8
       THETA=DCOS(BIDP)
       THETA2=THETA*THETA
       THETA4=THETA2*THETA2
   202 IF(IDMEAN.EQ.0)GO TO 155
       IF(IPASS.EQ.2) GO TO 150
C
C COMPUTE LDOT,GDOT,HDOT
C
   157 BLDOT=CN*ANU*(GMP2*(F3D2*(3.0*THETA2-1)+GMP2*F3D32*(THETA2
      1*(-96.0*CN+30.0-90.0*CN2)+(16.0*CN+25.0*CN2-15.0)+THETA4
      2*(144.0*CN+25.0*CN2+105.0)))+EDP2*GMP4*F15D16*(3.0+35.0*THETA4
      3-30.0*THETA2))
       GDOT=ANU*(F5D16*GMP4*((THETA2*(126.0*CN2-270.0)+THETA4*(385.0
      1-189.0*CN2))-9.0*CN2+21.0)+GMP2*(F3D32*GMP2*(THETA4*(45.0*CN2
      2+360.0*CN+385.0)+THETA2*(90.0-192.0*CN-126.0*CN2)+(24.0*CN
      3+25.0*CN2-35))+F3D2*(5*THETA2-1)))
       HDOT=ANU*(GMP4*F5D4*THETA*(3.0-7.0*THETA2)*(5.0-3.0*CN2)+GMP2
      1*(GMP2*F3D8*(THETA*(12.0*CN+9.0*CN2-5.0)-THETA*THETA2*(5.0*CN2
      2+36.0*CN+35.0))-3*THETA))
   155 IF(IFLG.EQ.1)GO TO 19
C
C COMPUTE ISUBC TO TEST CRITICAL INCLINATION
C
       BISUBC=((1.0-5.0*THETA2)**(-2))*((25.0*THETA4*THETA)*(GMP2*EDP2))
       IFLG=1
C
C FIRST CHECK FOR CRITICAL INCLINATION
C
       IF(BISUBC.GT.BKSUBC)GO TO 158
       ASSIGN 163 TO ID8
       GO TO 159



                                        F-9        NOAA POD Guide - Jan. 2002 Revision9
C
C IS THERE CRITICAL INCLINATION?
C
     19 IF(BISUBC.GT.BKSUBC)GO TO 150
   159 IF(IPERT.EQ.1)GO TO 150
        GM3=BK3/ADP**3
        GMP3=GM3/(CN2*CN2*CN2)
        GM5=BK5/ADP**5
        GMP5=GM5/CN**10
        G3DG2=GMP3/GMP2
        G4DG2=GMP4/GMP2
        G5DG2=GMP5/GMP2
C
C COMPUTE A1-A8
C
        A1=(F1D8*GMP2*CN2)*(1.0-11.0*THETA2-((40.0*THETA4)/(1.0-5.0*THETA2)))
        A2=(F5D12*G4DG2*CN2)*(1.0-((8.0*THETA4)/(1.0-5.0*THETA2))-3.0*THETA2)
        A3=G5DG2*((3.0*EDP2)+4.0)
        A4=G5DG2*(1.0-(24.0*THETA4)/(1.0-5.0*THETA2)-9.0*THETA2)
        A5=(G5DG2*(3.0*EDP2+4.0))*(1.0-(24.0*THETA4)/(1.0-5.0*THETA2)-9.0*THETA2)
        A6=G3DG2*F1D4
        SINI=DSIN(BIDP)
        A10=CN2*SINI
        A7=A6*A10
        A8P=G5DG2*EDP*(1.0-(16.0*THETA4)/(1.0-5.0*THETA2)-5.0*THETA2)
        A8=A8P*EDP
C
C COMPUTE B13-B15
C
        B13=EDP*(A1-A2)
        B14=A7+F5D64*A5*A10
        B15=A8*A10*F35384
C
C COMPUTE A11-A27
C
        A11=2.0+EDP2
        A12=3.0*EDP2+2.0
        A13=THETA2*A12
        A14=(5.0*EDP2+2.0)*(THETA4/(1.0-5.0*THETA2))
        A17=THETA4/((1.0-5.0*THETA2)*(1.0-5.0*THETA2))
        A15=(EDP2*THETA4*THETA2)/((1.0-5.0*THETA2)*(1.0-5.0*THETA2))
        A16=THETA2/(1.0-5.0*THETA2)
        A18=EDP*SINI
        A19=A18/(1.0+CN)
        A21=EDP*THETA
        A22=EDP2*THETA
        SINI2=DSIN(BIDP/2.0)
        COSI2=DCOS(BIDP/2.0)
        TANI2=DTAN(BIDP/2.0)
        A26=16.0*A16+40.0*A17+3.0
        A27=A22*F1D8*(11.0+200.0*A17+80.0*A16)
C
C COMPUTE B1-B12
C
        B1=CN*(A1-A2)-((A11-400.0*A15-40.0*A14-11.0*A13)*F1D16+(11.0+200.0
       1*A17+80.0*A16)*A22*F1D8)*GMP2+((-80.0*A15-8.0*A14-3.0*A13+A11)



                                        F-10        NOAA POD Guide - Jan. 2002 Revision10
       2*F5D24+F5D12*A26*A22)*G4DG2
        B2=A6*A19*(2.0+CN-EDP2)+F5D64*A5*A19*CN2-F15D32*A4*A18*CN*CN2
1+(F5D64*A5+A6)*A21*TAN12+(9.0*EDP2+26.0)*F5D64*A4*A18+F15D32*A3*
2A21*A26*SINI*(1.0-THETA)
        B3=((80.0*A17+5.0+32.0*A16)*A22*SINI*(THETA-1.0)*F35576 *G5DG2*EDP)
       1-((A22*TANI2+(2.0*EDP2+3.0*(1.0-CN2*CN))*SINI)*F35D52*A8P)
        B4=CN*EDP*(A1-A2)
        B5=((9.0*EDP2+4.0)*A10*A4*F5D64+A7)*CN
        B6=F35384*A8*CN2*CN*SINI
        B7=((CN2*A18)/(1.0-5.0*THETA2))*(F1D8*GMP2*(1.0-15.0*THETA2)+(1.0
       1-7.0*THETA2)*G4DG2*(-F5D12))
        B8=F5D64*(A3*CN2*(1.0-9.0*THETA2-(24.0*THETA4/(1.0-5.0*THETA2))))
       1+A6*CN2
        B9=A8*F35384*CN2
        B10=SINI*(A22*A26*G4DG2*F5D12-A27*GMP2)
        B11=A21*(A5*F5D64+A6+A3*A26*F15D32*SINI*SINI)
        B12=-((80.0*A17+32.0*A16+5.0)*(A22*EDP*SINI*SINI*F35576*G5DG2)+(A8
       1*A21*F35D52))
    150 IF (IPERT.EQ.0)GO TO 7
        IF (IDMEAN.EQ.0)GO TO 4
C
C COMPUTE SECULAR TERMS
C "MEAN" MEAN ANOMALY
C
        BLDP = ANU*DELT + BLDOT*DELT+BL0
        BLDP = DMOD(BLDP,PI2)
        IF(BLDP.LT.0.0D0)BLDP = BLDP + PI2
C
C MEAN ARGUMENT OF PERIGEE
C
        GDP = GDOT*DELT + G0
        GDP = DMOD(GDP,PI2)
        IF(GDP.LT.0.0D0)GDP = GDP + PI2
C
C MEAN LONGITUDE OF ASCENDING NODE
C
        HDP = HDOT*DELT + H0
        HDP = DMOD(HDP,PI2)
        IF(HDP.LT.0.0D0)HDP = HDP + PI2
      4 DO 33 NN=1,6
    33 OSCELE(NN) = DPELE(NN)
        A = ADP
        E = EDP
        BI = BIDP
        H = HDP
        G = GDP
        BL = BLDP
C
C COMPUTE TRUE ANOMALY (DOUBLE PRIMED)
C
        EADP = DKEPLR(BLDP,EDP)
        SINDE = DSIN(EADP)
        COSDE = DCOS(EADP)
        SINFD = CN*SINDE
        COSFD = COSDE - EDP
        FDP = DATAN0(SINFD,COSFD)



                                       F-11        NOAA POD Guide - Jan. 2002 Revision11
      IF(IPERT.EQ.1)GO TO 7
      DADR=(1.0-EDP*COSDE)**(-1)
      SINFD=SINFD*DADR
      COSFD=COSFD*DADR
      CS2GFD=DCOS(2.0*GDP+2.0*FDP)
      DADR2=DADR*DADR
      DADR3=DADR2*DADR
      COSFD2=COSFD*COSFD
C
C COMPUTE A (SEMI-MAJOR AXIS)
C
       A=ADP*(1.0+GM2*((3.0*THETA2-1.0)*(EDP2/(CN2*CN2*CN2))*(CN+(1.0/(1.
      1+CN)))+((3.0*THETA2-1.0)/(CN2*CN2*CN2))*(EDP*COSFD)*(3.0+3.0*EDP
      2*COSFD+EDP2*COSFD2)+3.0*(1.0-THETA2)*DADR3*CS2GFD))
       SN2GFD=DSIN(2.0*GDP+2.0*FDP)
       SNF2GD=DSIN(2.0*GDP+FDP)
       CSF2GD=DCOS(2.0*GDP+FDP)
       SN2GD=DSIN(2.0*GDP)
       CS2GD=DCOS(2.0*GDP)
       SN3GD=DSIN(3.0*GDP)
       CS3GD=DCOS(3.0*GDP)
       SN3FGD=DSIN(3.0*FDP+2.0*GDP)
       CS3FGD=DCOS(3.0*FDP+2.0*GDP)
       SINGD=DSIN(GDP)
       COSGD=DCOS(GDP)
       GO TO ID8, (163,164)
   163 DLT1E=B14*SINGD+B13*CS2GD-B15*SN3GD
C
C COMPUTE (L+G+H) PRIMED
C
       BLGHP=HDP+GDP+BLDP+B3*CS3GD+B1*SN2GD+B2*COSGD
       BLGHP=DMOD(BLGHP,PI2)
       IF(BLGHP.LT.0.0D0)BLGHP=BLGHP+PI2
       EDPDL=B4*SN2GD-B5*COSGD+B6*CS3GD-F1D4*CN2*CN*GMP2*(2.0*(3.0*THETA2
      1-1.0)*(DADR2*CN2+DADR+1.0)*SINFD+3.0*(1.0-THETA2)*((-DADR2*CN2
      2-DADR+1.0)*SNF2GD+(DADR2*CN2+DADR+F1D3)*SN3FGD))
       DLTI=F1D2*THETA*GMP2*SINI*(EDP*CS3FGD+3.0*(EDP*CSF2GD+CS2GFD))
     1-(A21/CN2)*(B8*SINGD+B7*CS2GD-B9*SN3GD)
       SINDH=(1.0/COSI2)*(F1D2*(B12*CS3GD+B11*COSGD+B10*SN2GD-(F1D2*GMP2
      1*THETA*SINI*(6.0*(EDP*SINFD-BLDP+FDP)-(3.0*(SN2GFD+EDP*SNF2GD)+EDP
      2*SN3FGD)))))
C
C COMPUTE (L+G+H)
C
   164 BLGH=BLGHP+((1.0/(CN+1.0))*F1D4*EDP*GMP2*CN2*(3.0*(1.0-THETA2)*
      1(SN3FGD*(F1D3+DADR2*CN2+DADR)+SNF2GD*(1.0-(DADR2*CN2+DADR)))+2.0*
      2SINFD*(3.0*THETA2-1.0)*(DADR2*CN2+DADR+1.0)))+GMP2*F3D2*((-2.0*
      3THETA-1.0+5.0*THETA2)*(EDP*SINFD+FDP-BLDP))+(3.0+2.0*THETA-5.0*
      4THETA2)*(GMP2*F1D4*(EDP*SN3FGD+3.0*(SN2GFD+EDP*SNF2GD)))
       BLGH=DMOD(BLGH,PI2)
       IF(BLGH.LT.0.0D0)BLGH=BLGH+PI2
       DLTE=DLT1E+(F1D2*CN2*((3.0*(1.0/(CN2*CN2*CN2))*GM2*(1.0-THETA2)
      1*CS2GFD*(3.0*EDP*COSFD2+3.0*COSFD+EDP2*COSFD*COSFD2+EDP))-(GMP2
      2*(1.0-THETA2)*(3.0*CSF2GD+CS3FGD))+(3.0*THETA2-1.0)*GM2*(1.0/
      3(CN2*CN2*CN2))*(EDP*CN+(EDP/(1.0+CN))+3.0*EDP*COSFD2+3.0*COSFD+
      4EDP2*COSFD*COSFD2)))



                                     F-12    NOAA POD Guide - Jan. 2002 Revision12
      EDPDL2=EDPDL*EDPDL
      EDPDE2=(EDP+DLTE)*(EDP+DLTE)
C
C COMPUTE E (ECCENTRICITY)
C
       E=DSQRT(EDPDL2+EDPDE2)
       SINDH2=SINDH*SINDH
       SQUAR=(DLTI*COSI2*F1D2+SINI2)*(DLTI*COSI2*F1D2+SINI2)
       SQRI=DSQRT(SINDH2+SQUAR)
C
C COMPUTE BI (INCLINATION)
C
       BI=DARSIN(SQRI)
       BI=2.0*BI
       BI=DMOD(BI,PI2)
       IF(BI.LT.0.0D0)BI=BI+PI2
C
C CHECK FOR E (ECCENTRICITY)=0
C
       IF(E.NE.0.0) GO TO 168
       BL=0.0
C
C CHECK FOR BI (INCLINATION)=0
C
   145 IF(BI.NE.0.0) GO TO 169
       H=0.0
C
C COMPUTE G (ARGUMENT OF PERIGEE)
C
   146 G=BLGH-BL-H
       G=DMOD(G,PI2)
       IF(G.LT.0.0D0)G=G+PI2
C
C COMPUTE TRUE ANOMALY
C
       EA = DKEPLR(BL,E)
       ARG1 = DSIN(EA) * DSQRT(1.0-E**2)
       ARG2 = DCOS(EA) - E
       IF = DATAN0(ARG1,ARG2)
       OSCELE(1) = A*AE
       OSCELE(2) = E
       OSCELE(3) = BI
       OSCELE(4) = H
       OSCELE(5) = G
       OSCELE(6) = BL
     7 CONTINUE
       DPELE(1) = ADP*AE
       DPELE(2) = EDP
       DPELE(3) = BIDP
       DPELE(4) = HDP
       DPELE(5) = GDP
       DPELE(6) =      BLDP
       IF(IPERT.EQ.0)BL = DMOD(ANU*DELT,PI2)
       ORBEL(1) = EADP
       ORBEL(2) = GDP+FDP
       ORBEL(3) = GDP



                                     F-13       NOAA POD Guide - Jan. 2002 Revision13
      ORBEL(4) = EK*(ANU + BLDOT)
      ORBEL(5) = FDP
      R = A*AE*(1.0D0 - E*DCOS(EA))
      GO TO 45
C
C MODIFICATIONS FOR CRITICAL INCLINATION
C
   158 DLT1E=0.0
       BLGHP=0.0
       EDPDL=0.0
       DLTI=0.0
       SINDH=0.0
       ASSIGN 164 TO ID8
       GO TO 150
   168 SINLDP=DSIN(BLDP)
       COSLDP=DCOS(BLDP)
       SINHDP=DSIN(HDP)
       COSHDP=DCOS(HDP)
C
C COMPUTE L (MEAN ANOMALY)
C
        ARG1=EDPDL*COSLDP+(EDP+DLTE)*SINLDP
        ARG2=(EDP+DLTE)*COSLDP-(EDPDL*SINLDP)
        BL=DATAN2(ARG1,ARG2)
        BL=DMOD(BL,PI2)
        IF(BL.LT.0.0D0)BL=BL+PI2
        GO TO 145
C
C COMPUTE H (LONGITUDE OF ASCENDING NODE)
C
    169 ARG1=SINDH*COSHDP+SINHDP*(F1D2*DLTI*COSI2+SINI2)
        ARG2=COSHDP*(F1D2*DLTI*COSI2+SINI2)-(SINDH*SINHDP)
        H=DATAN2(ARG1,ARG2)
        H=DMOD(H,PI2)
        IF(H.LT.0.0D0)H=H+PI2
        GO TO 146
     45 CONTINUE
        RETURN
        END




                                      F-14     NOAA POD Guide - Jan. 2002 Revision14
       SUBROUTINE CELEM (ORBEL,GMC,PV,VV)
C     ORIGINAL VERSION...1/22/71...CHARLES K. CAPPS
C     PURPOSE:
C                  THIS ROUTINE CONVERTS CLASSICAL OSCULATING ORBITAL
             ELEMENTS TO
C            CARTESIAN ELEMENTS.
C     CALLING SEQUENCE:
C            CALL CELEM(ORBEL,GMC,PV,VV)
C     INPUT THROUGH ARGUMENT LIST:
C                  ORBEL(1) = SEMI-MAJOR AXIS, A (OSCULATING ELEMENTS)
C                  ORBEL(2) = ECCENTRICITY, E
C                  ORBEL(3) = INCLINATION, I
C                  ORBEL(4) = LONGITUDE OF ASCENDING NODE, CAP OMEGA
C                  ORBEL(5) = ARGUMENT OF PERIFOCUS, OMEGA
C                  ORBEL(6) = MEAN ANOMALY, M
C                  GMC = GRAVITATIONAL CONSTANT
C     OUTPUT THROUGH ARGUMENT LIST:
C                  PV = CARTESIAN POSITION VECTOR
C                  VV = CARTESIAN VELOCITY VECTOR
C     METHOD:
C                  USES MILES STANDISH ITERATIVE SCHEME FOR SOLUTION TO
             KEPLERS EQN.
C     REFERENCES:
C                  GTDS TASK SPEC FOR CELEM, C.E. VELEZ, 13 JANUARY 1971
C                  DODS SYSTEM DESCRIPTION, SUBROUTINE KEPLR1
C                  P. EXCOBAL- "METHODS OF ORBIT DETERMINATION"
C                  X-552-67-421,"COMPARISON OF ITERATIVE TECHNIQUES FOR THE
             SOLUTION OF
C            KEPLERS EQUATION", I.COLE AND R.BORCHERS
C            PROGRAMMER:
C                  CHARLES K. CAPPS, CODE 553.2, GSFC
C
      IMPLICIT REAL*8(A-H,O-Z)
      DATA MAX /10/
      DIMENSION PV(3),VV(3),ORBEL(6)
      DATA TOL /+0.5D-16/
      ITER = 0
C     FIND IF THIS IS ELLIPTIC OR HYPERBOLIC ORBIT
      IF (ORBEL (1).LE.0.0D0.AND.ORBEL(2).GT.1.0D0) GO TO 50
C     ELLIPTIC ORBIT TAKES THIS ROUTE.
C     FIRST FIND ECCENTRIC ANOMALY VIA NEWTONS (MILES STANDISH VERSION)
      E1 = ORBEL(6)
 10   F = E1 - (ORBEL(2) * DSIN(E1)) - ORBEL (6)
      D = 1.0D0 - (ORBEL (2) * DCOS (E1 - 0.5D0 *F))
      E2 = E1 - (F / D)
      IF (DABS (E1-E2)-TOL)40,40,20
 20   ITER =ITER + 1
      E1 = E2
      IF(ITER - MAX) 10,10,30
C     SET UP ERROR CODE TO RETURN FROM SUBROUTINE
 30   NERR = 13
C     ECCENTRIC ANOMALY CONVERGED, NOW GET XO, YO, R
 40   COSE = DCOS(E2)
      SINE = DSIN (E2)
      TEMP = 1.0D0 - ORBEL(2) * ORBEL (2)



                                  F-15      NOAA POD Guide - Jan. 2002 Revision15
           XO = ORBEL(1) * (COSE - ORBEL(2))
           YO = ORBEL(1) * (DSQRT(TEMP)* SINE)
           R = ORBEL(1) * (1.0D0 - ORBEL (2) * COSE)
           XOD = (-DSQRT(GMC* ORBEL(1))* SINE)/R
           YOD = (DSQRT(GMC*ORBEL(1)*(TEMP))*COSE) /R
           GO TO 100
C          HYPERBOLIC ORBITS TAKE THIS ROUTE
     50   E1 = ORBEL(6) /2.0D0
     60   F = ORBEL(2) * DSINH(E1) - E1 - ORBEL(6)
           D = ORBEL(2) * DCOSH(E1 - 0.5D0 * F ) - 1.0D0
           E2=E1-(F/D)
           IF (DABS (E1-E2)-TOL)90,90,70
     70   ITER = ITER + 1
          E1 = E2
          IF (ITER - MAX) 60,60,80
C         SET UP ERROR CODE FOR NON-CONVERGENCE PRIOR TO EXIT.
    80    NERR = 14
C         ECCENTRIC ANOMALY COMPUTED, NOW GET XO,YO,R
    90    COSE = DCOSH (E2)
          SINE = DSINH(E2)
          TEMP = ORBEL(2) * ORBEL (2) - 1.0D0
          XO = ORBEL(1)*(COSE- ORBEL(2))
          YO = -ORBEL (1)*DSQRT (TEMP) * SINE
          R = ORBEL (1)*(1.0D0 - ORBEL(2) * COSE)
          XOD = (-DSQRT(-GMC*ORBEL(1))*SINE)/R
          YOD = (DSQRT(-GMC*ORBEL(1)*TEMP)*COSE)/R
    100   COSO = DCOS(ORBEL(5))
          SINO = DSIN (ORBEL(5))
          COSOM = DCOS (ORBEL(4))
          SINOM = DSIN (ORBEL(4))
          COSI = DCOS(ORBEL(3))
          SINI = DSIN (ORBEL(3))
          B11 = COSO * COSOM - SINO * SINOM * COSI
          B21 = COSO * SINOM + SINO * COSOM * COSI
          B31 = SINO * SINI
          B12 = -SINO * COSOM - COSO * SINOM * COSI
          B22 = -SINO * SINOM + COSO * COSOM * COSI
          B32 = COSO * SINI
C         NOW MULTIPLY 3 X 2 MATRIX BY 2 X 1 VECTORS FOR POSITION, VELOCITY.
          PV(1) = B11 * XO + B12 * YO
          PV(2) = B21 * XO + B22 * YO
          PV(3) = B31 * XO + B32 * YO
          VV(1) = B11*XOD + B12 * YOD
          VV(2) = B21 * XOD + B22 * YOD
          VV(3) = B31 * XOD + B32 * YOD
    999   RETURN
          END




                                       F-16       NOAA POD Guide - Jan. 2002 Revision16
      DOUBLE PRECISION FUNCTION DATAN0(ARG1,ARG2)
C                 VERSION OF 03/10/71
C
C                  FORTRAN IV FUNCTION SUBROUTINE FOR THE IBM-360
C
C                  PURPOSE
C                               COMPUTE A VALUE FOR THE ARCTAN BETWEEN 0
                   AND 2 PI WHERE THE
C                  TANGENT IS DEFINED BY THE TWO INPUT ARGUMENTS AS
ARG1/ARG2
C
C                  CALLING SEQUENCE
C                              NONE
C                  INPUT
C                              ARG1 - FIST ARGUMENT OF THE ARC TANGENT
C                              ARG2 - SECOND ARGUMENT OF THE ARC TANGENT
C
C                  OUTPUT
C                              A DOUBLE PRECISION ARC TANGENT (+ VALUE
                   BETWEEN 0 AND 2PI)
C
C                  METHOD
C
C                               USES FORTRAN MATH SUBROUTINE DATAN2 WHICH
                   RETURNS A VALUE
C                  BETWEEN -PI AND PI, GIVEN TWO ARGUMENTS
C
C                     REQUIRED SUBROUTINES
C                                    1- FUNCTION SUBROUTINE DATAN2
C
C                     PROGRAMMER
C                                    R. E. GILLIAN - COMPUTING AND SOFTWARE
C
C*********START PROGRAM********************************************
C
C                     COMPUTE ARCTAN BETWEEN -PI AND PI
C
        IMPLICIT REAL*8 (A-H,P-Z)
  50   DATAN0=DATAN2(ARG1,ARG2)
C
C       IF ARCTAN IS NEGATIVE, ADD 2PI TO THE RESULT
C
 100 IF(DATAN0.GE.0) GO TO 999
        DATAN0 = DATAN0 + 6.283185307179586D0
        ARG = DATAN0
 999   RETURN
        END
        FUNCTION DKEPLR(M,E)
        IMPLICIT REAL*8(A-H,O-Z)
        REAL*8 M,PI2/6.283185307179586D0/,TOL/0.5D-15/
C
C SUBROUTINE TO SOLVE KEPLER'S EQUATION
C KEPLER'S EQUATION RELATES GEOMETRY OR POSITION IN ORBIT PLANE TO TIME.
C
C M - MEAN ANOMALY (0<M<2PI)
C E - ECCENTRICITY



                                    F-17       NOAA POD Guide - Jan. 2002 Revision17
C EA - ECCENTRIC ANOMALY
C
        EA=0
        IF(M)1,2,1
     1 EA=M + E*DSIN(M)
        DO 22 I=1,12
        OLDEA=EA
        FE=EA-E*DSIN(EA)-M
        EA=EA-FE/(1-E*DCOS(EA-0.5D0*FE))
C TEST FOR CONVERGENCE
        DELEA=DABS(EA-OLDEA)
        IF(DELEA.LE.TOL)GO TO 2
    22 CONTINUE
     2 EA=DMOD(EA,PI2)
        DKEPLR=EA
        RETURN
        END
   SUBROUTINE MA3331(/A/,/B/,/C/)
C
C PURPOSE
C     TO COMPUTE THE PRODUCT OF A 3X3 MATRIX AND A 3X1 MATRIX
C
C VERSION OF JULY 23, 1971
C
C METHOD
C     WRITE THE EXPLICIT CODE FOR THE MULTIPLICATION OF A 3X3 MATRIX AND
C A 3X1 MATRIX AND RETURN THE RESULT IN THE 'C' MATRIX
C
C CALLING SEQUENCE
C     CALL MAT31(A,B,C)
C     A = INPUT 3X3 MATRIX
C     B = INPUT 3X1 MATRIX
C     C = OUTPUT 3X3 MATRIX
C
C PROGRAMMER
C     N.R. BURTON COMPUTER SCIENCES CORPORATION




                                   F-18       NOAA POD Guide - Jan. 2002 Revision18
C
C    **********START PROGRAM*******************************************
    IMPLICIT     REAL*8(A-H,O-Z)
    DIMENSION A(9),B(3),C(3)
    C(1)=A(1)*B(1)+A(4)*B(2)+A(7)*B(3)
    C(2)=A(2)*B(1)+A(5)*B(2)+A(8)*B(3)
    C(3)=A(3)*B(1)+A(6)*B(2)+A(9)*B(3)
    RETURN
    END
        SUBROUTINE XYZPLH(EQS,XSTA,YSTA,ZSTA,RLAT,RLON,AE,HE,IERR)
C
C                      FORTRAN IV SUBROUTINE FOR THE IBM-360, 3/20/74 VERSION
C                      PURPOSE
C                                     TO CONVERT STATION COORDINATES FROM THE
                       EARTH-FIXED CARTESIAN
C                      COORDINATES TO GEODETIC LATITUDE, EAST LONGITUDE, AND
SPHEROID C                    HEIGHT
C                      CALLING SEQUENCE
C                                     CALL
                       XYZPLH(EQS,XSTA,YSTA,ZSTA,RLAT,RLON,HE,IERR,AE)
C                      INPUT
C                                     EQS - ECCENTRICITY OF THE BODY SQUARED
C                                     AE - SEMI-MAJOR AXIS
C                                     XSTA - EARTH-FIXED CARTESIAN COORDINATE X
C                                     YSTA - EARTH-FIXED CARTESIAN COORDINATE Y
C                                     ZSTA - EARTH-FIXED CARTESIAN COORDINATE Z
C                      OUTPUT
C                                     RLAT - GEODETIC LATITUDE
C                                     RLON - EAST LONGITUDE
C                                     HE - SPHEROID HEIGHT
C                                     IERR - ERROR FLAG
C                                       0=HEIGHT CONVERGED
C                                       1=HEIGHT DID NOT CONVERGE
C                                       2=LONGITUDE IS UNDEFINED
C                      REQUIRED SUBPROGRAMS
C                                     DATAN0
C                      PROGRAMMER
C                                     R.E. GILLIAN, COMPUTING AND SOFTWARE
C*************************************************************
       IMPLICIT REAL*8(A-H,P-Z)
       IERR=0
       T=EQS*ZSTA
       XYSQ=XSTA**2+YSTA**2
       IF (DABS(ZSTA).GE.1.0D-15) GO TO 5
       HE = DSQRT(XYSQ) - AE
       RLAT = 0.0 D0
       GO TO 21
     5 DO 10 J = 1, 25
       ZT=ZSTA+T
       H1=DSQRT(XYSQ+ZT**2)
       SINPHI=ZT/H1
       ESQSP=EQS*SINPHI
       H2=AE/DSQRT(1.0D0-ESQSP*SINPHI)
       T1=H2*ESQSP
       IF(DABS((T1-T)/T1).LT..1D-14) GO TO 20



                                      F-19        NOAA POD Guide - Jan. 2002 Revision19
10 T=T1
    IERR=1
    GO TO 30
20 HE=H1-H2
    RLAT=DARSIN(SINPHI)
21 IF(XSTA.EQ.0.0D0) GO TO 40
    GO TO 25
40 IF(YSTA.EQ.0.0D0) IERR=IERR+2
    IF(IERR.GT.0) GO TO 30
    IF(YSTA.LT.0.0D0) GO TO 50
    RLON=3.14159265358793/2.0D0
    GO TO 30
50 RLON=3.14159265358793*1.5D0
    GO TO 30
25 RLON=DATAN0(YSTA,XSTA)
30 CONTINUE
    RETURN
    END




                                   F-20   NOAA POD Guide - Jan. 2002 Revision20
APPENDIX G:                  The NOAA Satellite Information System (NOAASIS) Internet
                             Web Site

NOAA's Satellite Information System, hereby referred to as NOAASIS, is a World Wide Web
site capable of disseminating a large number of computer files and messages to the
environmental satellite user community.

The purpose of NOAASIS is to provide technical information to a world-wide satellite user
community having express interest in the management and operation of NOAA's earth-observing
environmental satellites. It also provides a means of communicating with NESDIS to inquire
about NOAA satellite information that may not be on the NOAASIS, and provides limited
information about the environmental satellite operations of other countries.

Information posted on NOAASIS includes, but is not limited to: Polar and Geostationary Orbital
Elements, TBUS Messages, Two Line orbital Elements (NORAD TLE), monthly Satellite
Navigation Predicts, Sensor Calibration information, Eclipse Schedules, WEFAX Transmission
Schedules, Special Operational Notices, News Items, Electronic versions of Technical
Publications and other helpful instructive information.

The Department of Commerce is one of the largest information producers in the United States
Federal Government and one of its missions is to share this information with the public through
various dissemination programs, such as NOAASIS. The use of electronic media and formats
for information dissemination is an appropriate strategy and a cost-effective means to accomplish
this goal.

INTERNET ACCESS

The NOAASIS Uniform Resource Locator (URL) is: http:noaasis.noaa.gov/NOAASIS/. A
telephone dial-in Bulletin Board System, the NOAA.SIS, discontinued operation in October
1997.

Inquiries about the NOAASIS web site can be directed to:

   Direct Readout Coordinator
   NOAA NESDIS E/SP3
   Attn: W. Winston
   FOB 4, Room 3320
   5200 Auth Road
   Suitland, MD 20746-4304 USA
   Telephone 301 457-5681, FAX 301 568-8649, or
   Email to: satinfo@nesdis.noaa.gov




                                                   G-1           NOAA POD GUIDE - 11/98 Revision
Appendix H:          Conversion Algorithm for Orbital Parameters

This appendix contains software written in power BASIC that converts IBM double precision,
floating point numbers to their decimal equivalent. Between Sept. 8, 1992 - Sept. 21, 1992 and
Oct. 21, 1992 - Nov. 15, 1994, the orbital parameters that were added to the Level 1b dataset
header were IBM double precision floating point numbers. The conversion software is contained
below.

'HEXTODEC.BAS converts values from Level 1b header in hex notation to decimal
' (Print statements for illustration only)
'Notation:
'Default precision: 8 byte floating point
'$ indicates string variable
'% indicates a two byte integer
'# indicates 8 byte floating point
defdbl a-z         'Default precision for all variables 8 byte floating point
'Example values:
'True values
x0=2707.578247 : y0=-1855.599762 : z0=-6455.342772
'Values in hex from Level 1b header
x$="43A939407FED2027" : y$="C373F998A009F622" : z$="C4193757BFE7E1FB"
cls : print " X                Y               Z"
for n%=1 to 3
  select case n%
    'Select proper variable string
    case 1 : s$=x$ : case 2 : s$=y$ : case 3 : s$=z$
  end select
  hxdg$="&h"+mid$(s$,1,1) 'Take 1st hex digit (4 bits). "&h" indicates hex
  v=val(hxdg$)            'Find decimal value of hex digit using VAL function
  'If the value is  8, then 1st bit (sign bit)=1, and value is negative.
  ' If so, subtract 8 (sign bit) from value.
  if v>=8 then sign$="-" : v=v-8 else sign$="+"
  expnt=v*16 'Multiply by 16, since these are high order bits of exponent
  'Evaluate 2nd hex digit, but all bits are significant for value
  hxdg$="&h"+mid$(s$,2,1) : v=val(hxdg$)
  expnt=expnt+v-64 'Add the two values and subtract 64 for exponent value
  'Remaining 14 hex digits are fractional part of number
  ' Divide 1st by 16^1, 2nd by 16^2, etc., and sum
  frct=0#
  for i%=3 to 16
    hxdg$="&h"+mid$(s$,i%,1) : v=val(hxdg$)
    frct=frct+v/16^(i%-2)
  next i%
  'Multiply fractional part by 16^exponent, and make negative if sign bit set
  nmb=16^expnt*frct : if sign$="-" then nmb=-nmb
  select case n%
                                                 H-1           NOAA POD GUIDE - 11/98 Revision
   case 1 : x=nmb : locate 2,1 : print x0 : locate 3,1 : print x
   case 2 : y=nmb : locate 2,20 : print y0 : locate 3,20 : print y
   case 3 : z=nmb : locate 2,40 : print z0 : locate 3,40 : print z
 end select
next n%
stop

Note: For more information on how values are stored in IBM, refer to an IBM Assembler
Language reference manual.




                                                       H-2           NOAA POD GUIDE - 11/98 Revision
Appendix J:          Selected References

Brest, C.L. and W.B. Rossow, 1992, Radiometric Calibration and Monitoring of NOAA AVHRR
        data for ISCCP, Int. J. Remote Sensing, 13, 235-273.

Hastings, D., Matson, M., and Horvitz, A, editors, 1988, AVHRR, Photogrammetric Engineering
       and Remote Sensing, pp. 1469-1470.

IBM System/370 Principles of Operation, Tenth Edition (May 1983), International Business
      Machines Corporation.

Kidwell, Katherine B., April 1996, Global Vegetation Index User's Guide, NOAA/NESDIS, 126
      pp.

Memorandum from Karl W. Cox, SMSRC KLM Group to Pat Mulligan, NOAA/NESDIS/OSD
     regarding "Problems with distances between AVHRR GAC scan lines, scan line numbers
     and times in the GAC 1b datasets for NOAA-10 and NOAA-11, 1990, 24 pp.

NASA Pamphlet, Advanced TIROS-N (ATN) NOAA-E, 19 pp.

NASA and NESDIS Pamphlet, Advanced TIROS-N (ATN) NOAA-F, 20 pp.

NASA and NESDIS Pamphlet, Advanced TIROS-N (ATN) NOAA-G, 20 pp.

NASA and NESDIS Pamphlet, Advanced TIROS-N (ATN) NOAA-H, 20 pp.

NASA and NESDIS Pamphlet, Advanced TIROS-N (ATN) NOAA-I, 24 pp.

Neckel, H. and Labs, D., 1984, The solar radiation between 3300 and 12500 Angstroms, Solar
       Physics, Vol. 90, pp. 205-258.

Needham, Bruce H., 1991, Instrumentation and Services for the NOAA Polar Orbiting
      Operational Environmental Satellites (POES) in the 21st Century, paper given at the
      Satellite and Information Services Technical Workshop, Seventh International
      Conference on Interactive Information and Processing Systems for Meteorology,
      Oceanography and Hydrology, 71st AMS Annual meeting in New Orleans, LA, 4 pp.

Oslik, N., August 1, 1984, Solar Backscattered Ultraviolet Radiometer Version 2 (SBUV/2)
       Users Guide, Systems and Applied Sciences Corporation under contract to
       NOAA/NESDIS, 121 pp.

Paris, Cecil A., February 1994, NOAA Polar Satellite Calibration: A System Description,
        NOAA Technical Report NESDIS 77, Washington, D.C., 61 pp.
Planet, Walter G. (Editor), revised October 1988, Data Extraction and Calibration of TIROS-
        N/NOAA Radiometers, NOAA Technical Memorandum NESS 107 Revision 1, 130 pp.

                                                  J-1         NOAA POD GUIDE - 11/98 Revision
Price, J.C., 1991: Timing of NOAA afternoon passes. Int. J. Remote Sens., 12: 193-198.

Rao, C.R. Nagaraja, October 1987, Pre-Launch Calibration of Channels 1 and 2 of the Advanced
       Very High Resolution Radiometer, NOAA Technical Report NESDIS 36, 62 pp.

Rao, C.R. Nagaraja and J. Chen, August 1994, Post-Launch Calibration of the Visible and Near-
       Infrared channels of the Advanced Very High Resolution Radiometer on NOAA-7, -9, and
       -11 Spacecraft, NOAA Technical Report NESDIS 78, 22 pp.

Rao, C.R. Nagaraja and J. Chen, 1996, Post-Launch Calibration of the Visible and Near-Infrared
       channels of the Advanced Very High Resolution Radiometer on NOAA-14 Spacecraft,
       located on Internet at URL: http://orbit-net.nesdis.noaa.gov/ora/text/nrao02.txt, 2 pp.

Rao, C.R. Nagaraja and J. Chen, 1996, Calibration updates for the visible and near-infrared
       channels of the Advanced Very High Resolution Radiometer on the NOAA-14 spacecraft,
       located on Internet at URL: http://orbit-net.nesdis.noaa.gov/ora/text/nrao01.txt, 2 pp.

Rao, C.R. Nagaraja, J. Chen, F.W. Staylor, P. Able, Y.J. Kaufman, E. Vermota, W.R. Rossow
       and C. Brest, 1993a, Degradation of the visible and near-infrared channels of the
       Advanced Very High Resolution Radiometer on the NOAA-9 spacecraft: Assessment and
       recommendations for corrections, NOAA Technical Report NESDIS 70, U.S. Dept. Of
       Commerce, Washington, D.C.

Rao, C.R. Nagaraja, J.T. Sullivan, C.C. Walton, J.W. Brown, and R.H. Evans, June 1993b,
       Nonlinearity Corrections for the Thermal Infrared Channels of the Advanced Very High
       Resolution Radiometer: Assessment and Recommendations, NOAA Technical Report
       NESDIS 69, 31 pp.

Rao, P.K., S.J. Holmes, R.K Anderson, J.S. Winston and P.E. Lehr, editors, 1990, Weather
       Satellites: Systems, Data and Environmental Applications, AMS, Boston, Massachusetts.

Schwalb, Arthur, March 1978, The TIROS-N/NOAA A-G Satellite Series, NOAA Technical
      Memorandum NESS 95, 75 pp.

Schwalb, Arthur, February 1982, Modified Version of the TIROS-N/NOAA A-G Satellite Series
      (NOAA E-J) - Advanced TIROS-N (ATN), NOAA Technical Memorandum NESS 116, 23
      pp.

Smith, Mona and J. Green, September 1990, Direct Readout Note 90-1, NOAA/NESDIS, 20 pp.




                                                  J-2          NOAA POD GUIDE - 11/98 Revision
Appendix K:           Original Level 1b Formats Valid to Sept. 8, 1992

The original formats of the Level 1b data before any enhancements were implemented
are contained in this appendix. These formats are valid for Level 1b data collected after
the launch of TIROS-N and before Sept. 8, 1992. Tables K-1 and K-2 contain the format
of the GAC and LAC/HRPT data records before September 8, 1992, respectively. Table
K-3 contains the format of the quality indicators before September 8, 1994, while Table
K-4 contains the dataset header format before September 8, 1992. A detailed explanation
of the contents of the data records is contained in Sections 3.1 and 3.2.

              Table K-1. Format of GAC Data Record before September 8, 1992.
        Byte #             # of Bytes                        Contents
          1-2                    2      Scan line number from 1 to n
          3-8                    6      Time code (year, day, hour, minute, second)
         9-12                    4      Quality indicators
        13-52                   40      Calibration coefficients
          53                     1      Number of meaningful Solar Zenith angles and
                                        Earth location points appended to scan (n)
       54-104                   51      Solar Zenith angles
       105-308                 204      Earth location
       309-448                 140      Telemetry (HRPT minor frame format)
      449-3176                2728      GAC video data
     3177-3220                  44      Spare

       Table K-2. Format of LAC/HRPT Data Record before September 8, 1992.
  Record #      Byte #    # of Bytes                      Contents
     1             1-2          2    Scan line number
                   3-8          6    Time code
                  9-12          4    Quality indicators
                 13-52         40    Calibration coefficients
                   53           1    Number of meaningful Solar Zenith angles and
                                     Earth location points appended to scan
                54-104         51    Solar Zenith angles
               105-308        204    Earth location
               309-448        140    Telemetry (header)
              449-7400       6952    LAC/HRPT video data
     2          1-6704       6704    LAC/HRPT video data
             6705-7400        696    Spare

            Table K-3. Format of Quality Indicators before September 8, 1994.
  Byte #     Bit #                                Contents
    9          1      FATAL FLAG - Data should not be used for product generation.
               2      TIME ERROR - A time sequence error was detected while processing
                      this frame.



                                          K-1         NOAA POD Guide - Jan. 2002 Revision1
              3      DATA GAP - A gap precedes this frame.
              4      DATA JITTER - Resync occurred on this frame.
              5      CALIBRATION - Insufficient data for calibration.
              6      NO EARTH LOCATION - Earth location data not available.
              7      ASCEND/DESCEND - AVHRR Earth location indication of ascending
                     (=0) or descending (=1) data.
              8      P/N STATUS - Pseudo Noise (P/N) occurred (=1) on the frame, data
                     not used for calibration computations.
   10         1      BIT SYNC STATUS - Drop lock during frame.
              2      SYNC ERROR - Frame Sync word error greater than zero.
              3      FRAME SYNC LOCK - Frame Sync previously dropped lock.
              4      FLYWHEELING - Flywheeling detected during this frame.
              5      BIT SLIPPAGE - Bit slippage detected during this frame.
             6-8     SPARE
   11         1      TIP PARITY - In first minor frame.
              2      TIP PARITY - In second minor frame.
              3      TIP PARITY - In third minor frame.
              4      TIP PARITY - In fourth minor frame.
              5      TIP PARITY - In fifth minor frame.
             6-8     SPARE
   12        1-6     SYNC ERRORS - Number of bit errors in frame sync.
             7-8     SPARE

Table K-4. Format of Dataset Header Record before September 8, 1992.
     Byte #        # of Bytes                             Contents
        1                1      Spacecraft ID
        2                1      Data type
       3-8               6      Start time - time code from first frame of data
      9-10               2      Number of scans
     11-16               6      End time - time code from last frame of data
     17-23               7      Processing Block ID (ASCII)
       24                1      Ramp/Auto Calibration
     25-26               2      Number of data gaps
     27-32               6      DACS Quality
     33-34               2      Calibration Parameter ID
       35                1      DACS Status
     36-40               5      Spares, zero-filled
     41-84              44      44 character data set name (EBCDIC)
     85-end          variable   Spares, zero-filled to size of data record




                                       K-2         NOAA POD Guide - Jan. 2002 Revision2
Appendix L:                   Level 1b Formats Valid from Sept. 8, 1992 to Nov. 15,
                       1994

On Sept. 8, 1992, NESDIS implemented enhancements to the current NOAA polar
satellite Level 1b digital data format beginning with the orbits shown below. This
enhancement utilized spare bytes within the current data fields. These enhancements
arose as a result of several requests from users to increase the usefulness and accuracy of
Earth location information within the Level 1b data. The dataset header record now
includes osculating Keplerian and Cartesian orbital parameters. The size of data records
was increased in order to improve the accuracy of the solar zenith angle to one tenth of a
degree.

However, NESDIS detected a problem in the HRPT Level 1b data on Sept. 24, 1992.
The problem appeared as a dark line parallel to the orbit subtrack where the video data
was replaced with data intended for the spare bytes. Investigations revealed that the error
was present in all HRPT and LAC data since the update on Sept. 8, 1992. The updates
were removed on Sept. 24, 1994 and were re-implemented on Oct. 21, 1992. A summary
of affected orbits is listed below.

Between October 21, 1992 and Nov. 15, 1994, the orbital elements (Keplerian and
Cartesian) were in IBM floating point format. A conversion routine is included in
Appendix H.

The Dataset Header record for GAC and LAC/HRPT data has the format shown in Table
L-1. The orbital parameters which were included in the Dataset Header record were
written using a standard FORTRAN write as an 8 byte floating point number on an IBM
mainframe. The year, Julian day and milliseconds of day are stored as integers (in 2, 2
and 4 bytes, respectively). The TOVS Dataset Header record was not changed.

   Table L-1. Format of the AVHRR dataset header record between October 21, 1992
                                and November 15, 1994.
   Byte #     # of Bytes                            Contents
      1            1     Spacecraft ID
      2            1     Data Type
     3-8           6     Start Time
    9-10           2     Number of Scans
   11-16           6     End Time
   17-23           7     Processing Block ID (ASCII)
     24            1     Ramp/Auto Calibration
   25-26           2     Number of Data Gaps
   27-32           6     DACS Quality
   33-34           2     Calibration Parameter ID
     35            1     DACS Status
   36-40           5     Zero-filled
   41-82          42     42 character dataset name (EBCDIC)



                                            L-1         NOAA POD Guide - Jan. 2002 Revision1
    83-84           2       Blank-filled
    85-86           2       Year of Epoch for orbit vector
    87-88           2       Julian Day of Epoch
    89-92           4       Millisecond UTC epoch time of day
                                 Keplerian Orbital Elements
   93-100           8       Semi-major axis in kilometers
  101-108           8       Eccentricity
  109-116           8       Inclination in degrees
  117-124           8       Argument of Perigee in degrees
  125-132           8       Right Ascension of the Ascending Node in degrees
  133-140           8       Mean Anomaly in degrees
                          Cartesian Inertial True of Date Elements
  141-148           8       X component of position vector in kilometers
  149-156           8       Y component of position vector in kilometers
  157-164           8       Z component of position vector in kilometers
  165-172           8       X-Dot component of the velocity vector in km/second
  173-180           8       Y-Dot component of the velocity vector in km/second
  181-188           8       Z-Dot component of the velocity vector in km/second
  189-end        variable   Spares - Zero filled to the size of the data record (3220 or 7400)

The format of the GAC Level 1b data between Oct. 21, 1992 and Nov. 15, 1994 is
contained in Table L-2.

          Table L-2. Format of the GAC data record between October 21, 1992 and
                                      November 15, 1994.
         Byte #            # of Bytes                               Contents
           1-2                   2          Scan line number from 1 to n
           3-8                   6          Time code - year, Julian day, milliseconds
          9-12                   4          Quality indicators
         13-52                  40          Calibration coefficients
           53                    1          Number of meaningful Solar Zenith angles and
                                            Earth location points appended to scan (n)
        54-104                  51          Solar Zenith angles
        105-308                204          Earth location
        309-448                140          Telemetry (HRPT minor frame format)
       449-3176               2728          GAC video data
     3177-3196*                 20          Additional decimal portion of 51 Solar Zenith
                                            angles
      3197-3220                 24          Spares
 * Note: Additional data use 19 bytes and 1 bit (3 bits per angle); the first bit in 3196 is used;
 all others are spares.

Previously, the Solar Zenith angle was multiplied by 2, truncated, and only the integer
portion saved, giving a precision of 0.5. In order to store the angle to a precision of 0.1,


                                             L-2         NOAA POD Guide - Jan. 2002 Revision2
an integer ranging from 0 to 4 must be added to this value. The binary representation of
this integer requires 3 bits. For the 51 values of Solar Zenith angles stored per scan line,
153 bits (19 bytes and 1 bit) are necessary to store the extra precision bits. These bits are
stored in the same order as the angles beginning with byte 3177 in GAC data records (and
byte 14105 in LAC and HRPT data records.)

To use the extra precision, unpack the normal zenith angle field as usual. Take the 8-bit
part, convert to decimal, and divide by 2. To add in the extra precision, take the 3 bit part
from the corresponding field, convert it to decimal, divide by 10, and add it to the
original number.

For example: The solar zenith angle of 85.7 will be stored in the original byte as 171.
The extra 3 bits will contain 2. To restore the angle divide 171 by 2 to get 85.5 as
normal. Then take the 2 from the 3-bit area and divide by 10 giving .2. Add .2 to 85.5 to
restore the angle to 85.7.

With the new precision, an angle of 85.79 will be rounded instead of truncated. It will be
restored as 85.8.

The format of the LAC/HRPT data records between Oct. 21, 1992 and Nov. 15, 1994 are
contained in Table L-3.

 Table L-3. Format of the LAC/HRPT data records between October 21, 1992 and
                                    November 15, 1994.
  Record #         Byte #        # of Bytes                     Contents
      1               1-2              2    Scan line number
                      3-8              6    Time code
                     9-12              4    Quality indicators
                    13-52             40    Calibration coefficients
                      53               1    Number of meaningful Solar Zenith angles
                                            and Earth location points appended to scan
                   54-104             51    Solar Zenith angles
                  105-308            204    Earth location
                  309-448            140    Telemetry (header)
                 449-7400           6952    LAC/HRPT video data
      2            1-6704           6704    LAC/HRPT video data
                6705-6724             20    Additional decimal portion of 51 Solar
                                            Zenith angles
                6725-7400            676    Spares
 * Note: The additional data use 19 bytes and 1 bit (3 bits per angle); the first bit in
 14,124 is used; all others are spares.

The new system functioned properly for TOVS Level 1b data. However, problems with
the data record time codes in the GAC Level 1b data forced NESDIS to remove the
updates from the



                                            L-3          NOAA POD Guide - Jan. 2002 Revision3
AVHRR process. Initially, NESDIS tried turning the clock drift corrections off, but time
codes were still incorrect so the old process was resumed. TOVS Level 1b continues to
run under
the new process without clock drift corrections in the data. The AVHRR data will be
processed with the old on-line earth location software until updates can be reinstalled. A
list of affected orbits is provided below.

Enhancements began with the following TOVS orbits:
  NOAA-12
       clock corrections on
          S1359.E1539.B1722526.GC
       clock corrections off
          S1723.E1900.B1722728.GC
          S1534.E1727.B1722627.GC

   NOAA-11
      clock corrections on
         S1542.E1719.B3068687.GC
         S1353.E1547.B3068586.GC
      clock corrections off
         S1904.E2026.B3068889.WI
         S1715.E1908.B3068788.WI

The following AVHRR data was processed under the enhanced system (only GAC data
showed timecode errors produced by the software changes):

NOAA-12
 clock corrections on
   HRPT - S1542.E1550.B1722626.GC
   LHRR - S1402.E1402.B1722525.GC ***time sequence errors**
   GHRR - S1359.E1539.B1722526.GC
   LHRR - S1359.E1411.B1722525.GC
   LHRR - S0934.E0946.B1722222.GC
   HRPT - S1902.E1914.B1722828.GC
 clock corrections off
   GHRR - S1723.E1900.B1722728.GC
   GHRR - S1534.E1727.B1722627.GC
   LHRR - S1729.E1738.B1722727.GC
   LHRR - S1652.E1658.B1722627.GC
   LHRR - S1532.E1543.B1722626.GC

NOAA-11
 clock corrections on
   HRPT - S1722.E1734.B3068787.GC
   GHRR - S1542.E1719.B3068687.GC
   GHRR - S1353.E1547.B3068586.GC



                                           L-4         NOAA POD Guide - Jan. 2002 Revision4
    LHRR - S1516.E1527.B3068686.GC
    LHRR - S1511.E1521.B3068586.GC
    LHRR - S1342.E1353.B3068585.GC

NOAA-9
 clock corrections on
   GHRR - S0825.E1019.B5019596.WI
   GHRR - S0128.E0321.B5019092.WI

Note that orbit parameters in the TOVS data header records are now scaled integers. The
same parameters in the AVHRR data header records are still IBM real numbers.

Initial Update on September 8, 1992:

                            JDAY          Start time          End time             Orbit
 NOAA-12 GAC          252              1823Z               2006Z               B0686566.GC
 NOAA-11 GAC          252              1719Z               1749Z               B2039394.WI
 NOAA-11 HRPT         252              1756Z               1805Z               B2039393.GC

All updates were removed from the operation on Thursday, September 24, 1992.

Reinstallation on October 21, 1992:

The update was implemented but system restrictions prevented the addition of the orbital
parameters in the header. The following orbits were processed adding only the extra
precision bits.

                            JDAY          Start time          End time             Orbit
 NOAA-12 GAC          295              1945Z               2130Z               B0747778.GC
 NOAA-12 HRPT         295              2133Z               2142Z               B0747878.GC
 NOAA-12 HRPT         295              2312Z               2320Z               B0747979.GC
 NOAA-11 GAC          295              1858Z               2044Z               B2100002.WI
 NOAA-11 LAC          295              2030Z               2041Z               B2100101.WI
 NOAA-11 GAC          295              2039Z                2233Z              B2100103.GC
 NOAA-11 HRPT         295              2238Z               2249Z               B2100303.GC

Final update on October 21, 1992:

The operational JCL was modified to correct the system problems and add the orbit
parameters to the header data. Beginning with the following orbits all updates were
available within the data.

                            JDAY          Start time          End time             Orbit
 NOAA-12 GAC          295              2126Z               2309Z               B0747879.GC
 NOAA-12 LAC          295              1622Z               1634Z               B0747575.GC



                                          L-5          NOAA POD Guide - Jan. 2002 Revision5
NOAA-11 GAC    295   2229Z       0016Z               B2100304.GC
NOAA-11 LAC    295   2040Z       2048Z               B2100102.GC
NOAA-11 HRPT   296   0018Z       0030Z               B2100404.GC




                       L-6   NOAA POD Guide - Jan. 2002 Revision6
Appendix M:            New HIRS Calibration Procedure (NOAA-12 Only)

The original HIRS calibration procedure (described in Section 4.5 of the NOAA Polar
Orbiter Data User’s guide) uses the fixed calibration coefficients calculated from the last
calibration scans on the first half scans of a superswath and those calculated from the
following calibration scans on the second half of the superswath. This method causes a
jump in the values of the brightness temperatures at the center of a superswath and it does
not take into consideration the change of the environmental temperatures through a
superswath.

The new calibration procedure bass the calibration on the information from calibration
scans at both ends of a superswath but also takes into account the change of the
environmental temperatures. The input data to the new calibration software is a
superswath of HIRS Level 1b data and the slopes and intercepts for 43 scan lines are the
output. There are a total of 43 scan lines in a superswath; with scan lines 1-3 and 41-43
containing calibration scans which start with a space-view scan, followed by a cold-
blackbody-view scan; and scan lines 4-40 being earth-view scans.

The coefficients between instrument temperatures and the calibration coefficients were
calculated from a test data set and are saved in the file: predcoef.txt.

The calibration coefficients at the two ends are calculated. Only the last 48 spots of both
space-view and warm-blackbody-view scan are used in the calibration. FI the count
value at a spot is off (>3 counts) from the average of the line, it is filtered out. At the
same time, the calibration coefficients are predicted from the instrument temperatures
with the coefficients from ‘predcoef.txt’. The difference between the calculated and
predicted coefficients is saved as the bias.

The calibration coefficients of the earth-view scans are also predicted from the instrument
temperatures. The predicted slopes and intercepts are adjusted to remove the biases at the
two ends so that the predicted and calculated values agree at these two points. The bias
corrections for the intervening earth data are interpolated from the two end values.

This package contains the programs and necessary data to process HIRS Level 1b data
and obtain the brightness temperatures (BT) of the HIRS channels. A new calibration
procedure is implemented in this package. This package is suitable for big endian
platforms. If the user wants to use it on a little endian platform, them it must be modified
accordingly. Many compilers have options to do this, but it should be noted that the
program uses bit patterns for flags and these must be changed as well. The following
lists the names and a brief description of the software, data and common areas used in
this package. The sample input datasets and outputs are separate files which can be
downloaded by clicking on the individual links listed below. (Please be patient – some of
these files are fairly large and take some time to download.)

      superdata.dmn and tooli.cmn: Two common blocks.
      hirsbt: The main program to do the processing.


                                           M-1          NOAA POD Guide - Jan. 2002 Revision1
      newhirscali: subroutine to get the new calibration.
      brighttn: Function to convert NOAA-12 radiances to brightness temperatures.
      gethirs: subroutine to calculate the HIRS BT for one superswath of data.
      i2move: Subroutine to move data from target array to source array.
      rdhdr: Subroutine to read the HIRS, MSU SSU Level 1b dataset header records
      readim: Function to ready allowed temperature limits for HIRS, MSU and SSU,
       then convert to radiance limits.
      tme1b: Subroutine to convert time code to day, hours, minutes and seconds.
      predcoef.txt: The coefficients for predicting calibration coefficients (NOAA-12).
      hirs0955.dat: (originally named: nss.hirx.nd.d92002.s0955.e1146.b0330708.wi)
       and hirs1851.dat (originally named: nss.nd,d92321.s1851.e2036.b0784647.gc):
       Sample of HIRS Level 1b data sets.
      bt0955.dat and bt1851.dat: Sample output in ASCII format.

It should be noted that this package works only for NOAA-12 only. If a user wants to
use it on other satellite’s HIRS observations (TIROS-N, NOAA-6 through NOAA-14
series), some coefficients (such as predcoef.txt, cofw1, bandc and waven) need to be
changed accordingly.

Note that the Planck formula constants used in the function brightn and subroutine
newhirscali are the old values at the time the data were processed. The newer values
recommended by the 1998 Committee on Data for Science and Technology (CODATA)
are C1 = 1.1910427 x 10-5 mW/(m2-sr-cm-4) and C2 = 1.4387752 cm-K. The effect of
these new constants on the temperature values is very small. For some uses, it may be
appropriate to change to the new values.

The following are two common blocks that are used throughout this calibration
procedure:

c
c                    *** common superdata ***
c
c    used for HIRS superswath data processing package *********
C!   suphirs(2128,43)          int*2    a superswath of Level1b data
C!                                      43 scanlines, 1-3,41-43
C!                                      calibration scans, 4-40
C!                                      earth view scans.
C!   hirsdat(35,56,40)         real*4   a superswath of result BT
C!                                      i=1,35;j=1,56,k=1,40
C! i: the order of the parameters 1-35;
C! j: the spot sequence 1-56;
C! k: the scan num of the superswath 1-40;
C! **************************************************
C! parameters:
C! i=1: flag =1 earth view &amp; good quality
C!             =2 space view &amp; good quality
C!             =3 cold blackbody &amp; good quality
C!             =4 warm blackbody &amp; good quality
C!             =-1 bad quality
C!             =-2 rain detected


                                         M-2          NOAA POD Guide - Jan. 2002 Revision2
C!             =-3 cloud detected
C!
C! i=2: latitude
C! i=3: longitude
C! i=4: year
C! i=5: julian day
C! i=6: UTC time
C! i=7: height
C! i=8: local zenith angle
C! i=9: HIRS channel 1 BT
C! i=10: HIRS channel 2 BT
C! ......
C! ......
C! i=26: HIRS channel 18 BT
C! i=27: HIRS channel 19 BT
C! i=28: HIRS channel 20 BT
C! i=33: flag for calibration: 1 good;
C!                              -1 head suspicious (too many spots
thrown away);
C!                              -2 tail suspicious;
C! i=other: reserved for future use
C! ***************************************************
c
  integer*2 suphirs, irfail
  real*4 hirsdat
  common/superdata/suphirs(2128,43),hirsdat(35,56,40),irfail
c
c                *** common toohi ***
c
c      version 1.0   6/11/80 g.domm (sasc)
c      limits on HIRS, MSU, SSU data allowed to be written to output
c             datasets of preprocessor.
c      6/20/83 limits stored are now radiances instead of temps (f.c.)
c      used by hircal,msucal,ssucal,readlm,rfldp,$tprps
c
  real toohih(20),tooloh(20)
  real toolom(4),toohim(4)
  real toohis(3),toolos(3)
c
  common /toohi/toohih,tooloh,toohim,toolom,toohis,toolos
c


The following listings are FORTRAN programs or functions that calculate the HIRS
calibration for NOAA-12 data.

program hirsbt
C!**************************************************************
C! main program to get HIRS channels 1-19 brightness temperature and
C! channel 20 albedo from HIRS Level1b data. Use a new calibration
package
C! newhirscali.f                            12/04/01
C!
C! This version is for big endian platforms!!!!
C! If used on little endian machine, need some switch on
C! variables associated with equivalence.



                                        M-3         NOAA POD Guide - Jan. 2002 Revision3
C!**************************************************************
c***************************************************************
c    key local parameters-
c       variable                type function
c       --------                ---- --------
C!         isexp                 int   expected next scan num
C!         isact                 int   actual scan num
C!         idiff                 int   isact-isexp
C!         isup                  int   seq num of the contingent
superswath
C!         iirec                 int   the seq of recorded superswath
C!         hunit                 int   input lun
C!         hirsdat             real*4 output data for a superswath
C!         nameh                char* input data file
C!         ounit                 int   output lun
C!         nameout              char* output data file
C!         nhirs                int*2 one scan of Level 1b data
C          satid                 int   satellite id
C!         sflags                int   view flags of scan
C!         suphirs               int*2 a superswath of Level 1b data
C!
c    subprograms called - readlm, rdhdr, gethirs
c
c    restrictions- none
c
c***************************************************************
c*
  include 'superdata.cmn'
  include 'toohi.cmn'
  integer*2 ifill,satid
  character*120 nameh
  character*80 nameout
c
  integer*4 sflags,hunit,ounit,iirec,idiff
  integer*4 isup
  integer*2 nfl(2),nhirs(2128),isexp, isact
  equivalence (sflags,nfl(1))
c
cllllllllllllllllllllllllllllllllllllllllllllllllllllllllllll
c
  data ifill/'Z7FFF'/
clllllllllllllllllllllllllllllllllllllllllllllllllllllllllll
c      open HIRS &amp; MSU Level 1b data , open geography, albedo, sft
files
clllllllllllllllllllllllllllllllllllllllllllllllllllllllllll
  hunit = 20
  ounit = 30
c==================================================================
c    read allowed limits on radiances in input data
c
  call readlm
clllllllllllllllllllllllllllllllllllllllllllllllllllllllllllll
  iirec=0
  irfail=0
  print *, 'Please input the HIRS Level 1b filename:'
  read(*,*)nameh
C!     nameh='hirs0955.dat'


                                  M-4       NOAA POD Guide - Jan. 2002 Revision4
  nameout='hirsbt'//nameh(14:18)//nameh(21:24)//nameh(27:30)//'.dat'
  print *, nameout
  open(ounit,file=nameout,form='formatted',
  .      status='unknown')
  open(hunit,
  . file=nameh,
  . form='unformatted', status='old'
  . ,access='direct',recl=4256)
clllllllllllllllllllllllllllllllllllllllllllllllllllllllllll
c       read HIRS header record
clllllllllllllllllllllllllllllllllllllllllllllllllllllllllll
c
  call rdhdr(hunit,5,4256,numsch,numdgh,iredtm,'hirs',satid)
  nrec=1
  !try to read here
  ! read(hunit,rec=1,iostat=jstat) nhirs
C! print *,'hdr hirs'
C! print *,numsch,numdgh,satid
clllllllllllllllllllllllllllllllllllllllllllllllllllllllllll
c     construct a superswath, and goto 5100 try to find
c     the start scanline of a superswath
clllllllllllllllllllllllllllllllllllllllllllllllllllllllllll
C! check whether start from space, if so
C! start the superswath, if else, go to find the start
  5100 isup=0
  nrec=nrec+1
  read (hunit, rec=nrec, end=5120, iostat=ioerr) nhirs
C! nflags
C! if for little endian platform, switch 1&amp;2 for all following nfl
  nfl(1)=nhirs(5)
  nfl(2)=nhirs(6)
  if(btest(sflags,25)) go to 5100
  if (.not.btest(sflags,24)) go to 5100
C!       print * , 'First scanline=', nhirs(1)
  do in=1,2128
  suphirs(in,1)= nhirs(in)
  enddo
C! suppose to read the cold and warm blackbody records
  do ir=1,2
  nrec=nrec+1
  read (hunit, rec=nrec,end=5120, iostat=ioerr) nhirs
  do in=1,2128
  suphirs(in,1+ir)= nhirs(in)
  enddo
  enddo
C! nflags
  nfl(1)=nhirs(5)
  nfl(2)=nhirs(6)
  if(.not. btest(sflags,25) .or. .not. btest(sflags,24)) then
  print *, 'Not the warm blackbody scan!'
  go to 5100
  endif
  isexp=nhirs(1)+1
c...     do loop 350 processes superswath 1 to 30 (usually #superswaths
&lt;26 in a file)
  do 350 idatps=1,30
  mumss=idatps


                                  M-5       NOAA POD Guide - Jan. 2002 Revision5
  ipasct=idatps
  iswfal=6
C! if not the contingent superswath then assign the last superswath's
C! last 3 line as the first 3 line of new swath
  if( isup .ne. 0) then
  do in=1,2128
  suphirs(in,1)= suphirs(in,41)
  suphirs(in,2)= suphirs(in,42)
  suphirs(in,3)= suphirs(in,43)
  enddo
  endif
c...    do loop 330 processes 40 lines of the superswath
c
  idiff=0
  do 330 iss=4,40    !from first earth view to last earth view
  if (idiff .gt.0) go to 320
  5500 nrec=nrec+1
  read (hunit, rec=nrec, end=5120, iostat=ioerr) nhirs
  print *,'The scanline #',nhirs(1)
  isact=nhirs(1)
C!    check whether a gap in the data
  if (isact .gt. isexp) then
  print *, 'There is a gap between scan lines!' ,isact,isexp
  idiff=isact - isexp
  if(idiff .gt. 10) go to 5100
C! still put the scan in the position
  do in=1,2128
  suphirs(in,iss+idiff)= nhirs(in)
  enddo
  go to 320
  else if (isact .lt. isexp) then
  go to 5500
  endif
  do in=1,2128
  suphirs(in,iss)= nhirs(in)
  enddo
  goto 328
  320 do in=1,2128
  suphirs(in,iss)= -9999
  enddo
  idiff=idiff-1
  328 isexp = nhirs(1)+1
  330 continue
C! continue to read the next calibration part
  nrec=nrec+1
  read (hunit, rec=nrec, end=5120, iostat=ioerr) nhirs
  isact=nhirs(1)
C!        print * , 'scanline=', nhirs(1)
C!    check whether a gap in the data
  if (isact .ne. isexp) then
  print *, 'There is a gap between scan lines!'
  print *, 'Pay attention to the flag of the scan!!'
  endif
C! nflags
  nfl(1)=nhirs(5)
  nfl(2)=nhirs(6)
  if(btest(sflags,25)) then


                                  M-6       NOAA POD Guide - Jan. 2002 Revision6
  print *, 'Not the space line? Go back for a new superswath!'
  go to 5100
  endif
  if (.not.btest(sflags,24)) then
  print *, 'Not the space line? Go back for a new superswath!'
  go to 5100
  endif
C!    if really a space view
  do in=1,2128
  suphirs(in,41)= nhirs(in)
  enddo
C! suppose to read the warm blackbody records
  do ir=1,2
  nrec=nrec+1
  read (hunit, rec=nrec,end=5120, iostat=ioerr) nhirs
  do in=1,2128
  suphirs(in,41+ir)= nhirs(in)
  enddo
  enddo
C! nflags
  nfl(1)=nhirs(5)
  nfl(2)=nhirs(6)
  if(.not. btest(sflags,25) .or. .not. btest(sflags,24)) then
  print *, 'Not warm blackbody! Not a valid superswath!'
  print *, 'Start to find a new super swath!!'
  go to 5100
  endif
C! set a new isexp ........
  isexp=nhirs(1)+1
  isup=isup+1
C!       print * , '#',isup, '    superswath'
C!*************************************************************
C! finished construction of a superswath
C!*************************************************************
c
c...    process HIRS data
c
  call gethirs
C! if fail in processing the superswath, go to next
if(irfail .eq. 1) go to 350
C! output the result *************************
  iirec=iirec+1
  print *,iirec
  write(ounit,*)iirec
write(ounit,900)(((hirsdat(i,j,k),i=1,35),j=1,56),k=1,40)
  900 format(7F12.3)
  350 continue
cl
  360 continue
  close(hunit)
  close(ounit)
  5120 stop
  end



 subroutine   newhirscali(pslope,pintcpt)


                                   M-7      NOAA POD Guide - Jan. 2002 Revision7
C**********************************************************************
***
C! This subroutine inputs a superswath of the HIRS Level 1b data,
outputs
C! the calibration coefficients for channels 1-19
C**********************************************************************
***
C! Description of variables:
!
! suphirs : input superswath, 43 lines (1-3, 41-43 calibration scans,
4-40 earthview)
! pslope : output slope
! pintcpt : output intercept
!
! band,bandc : HIRS/2 band correction coefficients
! c1,c2     : parameters for calculating radiance
! cofw,cofw1 : coefficients for warm blackbody brightness temperature
! coslope : coefficients for predicting slope
! cointcpt: coefficients for predicting intercepts
! iord      : order of each channel's location in the data set
! irfail : flag: 0: good calibration; 1: bad calibration
! mfq       : quqlity info for each spot
! nflags : flags for each scan line
! nslope : calculated slope at two ends
! nintcpt : calculated intercept at two ends
! onehir : one scan line of HIRS data
! prtw      : warm blackbody temperature
! prtrad : radiance from the warm blackbody
! scount : space view counts
! wcount : warm blackbody view counts
! warmt     : warm blackbody temperature counts
! sinst     : space scan instrument temperatures (counts)
! winst     : warm blackbody scan instrument temperatures (counts)
! tstar     : band corrected warm blackbody temperature
!
C**********************************************************************
***
  include 'superdata.cmn'
C!       integer*2 suphirs(2128,43)
  real*4   pslope(43,19),pintcpt(43,19)
  real*4   prtw(4),band(38),bandc(2,19)
  real*4   difslope(2,19),difintcpt(2,19),cofw(5,4),cofw1(20)
  real*4   waven(20),ainst(8),coslope(9,19),cointcpt(9,19)
  integer*2 sinst(8),winst(8),iord(20)
  integer*2 scount(56,20),wcount(56,20),warmt(20)
  integer*2 onehir(2128)
  integer*4 nflags,ind(2),irfail
  logical*1 mfq(56)
  real*4 tstar(19),smean(19),wmean(19),prtrad(19)
  real*4 nslope(2,19),nintcpt(2,19)
C! Some flags
  equivalence (mfq(1),onehir(1891)),(nflags,onehir(5))
C!     IWT PRT Count to temperature coefficients, this is for NOAA12
  data cofw1/
  1   301.38300,6.52454E-03,8.63834E-08,4.81705E-11,1.17918E-15,
  2   301.38490,6.51937E-03,8.61601E-08,4.81257E-11,1.17221E-15,
  3   301.39920,6.51150E-03,8.58417E-08,4.80590E-11,1.17105E-15,


                                  M-8       NOAA POD Guide - Jan. 2002 Revision8
 4   301.38770,6.52702E-03,8.63606E-08,4.81834E-11,1.177669E-15/
 data waven/
 1 667.58,680.18,690.01,704.22,716.32,732.81,751.92,900.45,
 2 1026.66,1223.44,1368.68,1478.59,2190.37,2210.51,2236.62,
 3 2267.62,2361.64,2514.68,2653.48,14453.14 /
 data iord/1,3,4,6,16,15,10,11,20,13,8,18,5,14,17,19,2,7,9,12/
 data ind/1,41/
 data band/
 1   0.007,0.99996 , 0.007,0.99995 , 0.019,0.99989 , 0.026,0.99988,
 2   0.021,0.99990 , 0.140,0.99964 , 0.058,0.99982 , 0.358,0.99940,
 3   0.181,0.99985 , 0.377,0.99975 , 0.175,0.99992 , 0.265,0.99863,
 4   0.078,1.00042 , 0.017,0.99995 , -0.023,0.99950 ,0.021,0.99995,
 5   0.022,0.99997 , 0.058,0.99992 , 0.344,0.99950 /
 c1=1.1910659E-5
 c2=1.438833
C! read in coefficients for predicting calibration coefficients
 open(11,file='predcoef.txt',status='old')
 read(11,*)
 do k=1,19
 read(11,*) (coslope(i,k),i=1,9)
 enddo
 read(11,*)
 do k=1,19
 read(11,*) (cointcpt(i,k),i=1,9)
 enddo
 close(11)
C! initialize the slope and intercept array
 do i=1,43
 do j=1,19
 pslope(i,j)= 0.0
 pintcpt(i,j)= 0.0
 enddo
 enddo
C! First get the calibration coeff for both ends of the superswath
 do 100 iii=1,2      ! for two ends
C! initialize counts
 do i=1,56
 do j=1,20
 scount(i,j)=-9999
 wcount(i,j)=-9999
 enddo
 enddo
C! assign space scan to onehir
 do i=1,2128
 onehir(i)=suphirs(i,ind(iii))
 enddo
C! check the flags
 if(btest(nflags,25)) then
 print *, 'First line is not a space line!'
 return
 endif
 if (.not.btest(nflags,24)) then
 print *, 'First line is not a space line!'
 return
 endif
 do k=1,20   !20 channels
 m = iord(k)


                                  M-9       NOAA POD Guide - Jan. 2002 Revision9
 do 110 i = 1,56
 imfq=mfq(i)
 if(btest(imfq,2)) goto 110
 j = 484 + (i-1) * 22 + m
 scount(i,k)=onehir(j)
 110   continue
 enddo     !k=1,20
C! instrument temp count
 do it=1,8
 sinst(it)=onehir(484 + (62*22)+it)
 enddo
C! now the warm target count
C! assign warm target scan to onehir
 do i=1,2128
 onehir(i)=suphirs(i,ind(iii)+2)
 enddo
 awarmc = 0.0
 do k=1,20
 m = iord(k)
 do 120 i = 1,56
 imfq=mfq(i)
 if(btest(imfq,2)) goto 120
 j = 484 + (i-1) * 22 + m
 wcount(i,k)=onehir(j)
 120 continue
 enddo !k=1,20
C! Add sth here, warm BB temp and instrument temp
 do it=1,20
 warmt(it)=onehir(484 + (58*22)+it)
 enddo
 do it=1,8
 winst(it)=onehir(484 + (62*22)+it)
 enddo
C! calculate the warm BB radiance according to temperature
 tprtw = 0.0
 do 130 i= 1,4
 wsum=0.0
 do 131 j=1,5
 kk=(i-1)*5+j
 if (warmt(kk) .gt. -9999 .and. warmt(kk) .lt. 32760) then
 wsum=wsum+warmt(kk)
 endif
 cofw(j,i)=cofw1((i-1)*5+j)
 131 continue
 wsum=wsum/5.0
 prtw(i) = cofw(1,i) + cofw(2,i)*wsum + cofw(3,i)*wsum*wsum
 1 + cofw(4,i)*wsum*wsum*wsum + cofw(5,i)*wsum*wsum*wsum*wsum
 tprtw=tprtw + prtw(i)
 130 continue
 tprtw=tprtw/4.0
 do k=1,19
 bandc(1,k)=band((k-1)*2+1)
 bandc(2,k)=band(k*2)
 tstar(k)=tprtw * bandc(2,k) + bandc(1,k)
 s1 = c1*waven(k)*waven(k)*waven(k)
 s2 = exp( (c2* waven(k))/tstar(k)) -1
 prtrad(k) = s1/s2


                                M-10       NOAA POD Guide - Jan. 2002 Revision10
 enddo !k=1,19
C! calculate the mean of the space count and warm count for spots 9-56
 do 140 k=1,19
 smean(k)=0.0
 wmean(k)=0.0
 ismean=0
 iwmean=0
 nums=0
 numw=0
 do i=9,56
 if (scount(i,k) .gt. -9999 .and. scount(i,k) .lt. 32760) then
 ismean=ismean+scount(i,k)
 nums=nums+1
 endif
 if(wcount(i,k) .gt. -9999 .and. wcount(i,k) .lt. 32760 ) then
 iwmean=iwmean+wcount(i,k)
 numw=numw+1
 endif
 enddo !i=9,56
 if (nums .gt. 0) then
 ismean= ismean/nums
 else
 print *,'nums=',nums
 irfail=1
 return
 endif
 if (numw .gt. 0) then
 iwmean = iwmean/numw
 else
 print *,'numw',numw
 irfail=1
 return
 endif
C! Add filter here to filter out the off data in a line and redo the
calculation of mean
 nums=0
 numw=0
 do i=9,56
 if (scount(i,k) .gt. -9999 .and. scount(i,k) .lt. 32760 .and.
 2         abs(scount(i,k)-ismean) .le. 3    ) then
 smean(k)=smean(k)+scount(i,k)
 nums=nums+1
 endif
 if(wcount(i,k) .gt. -9999 .and. wcount(i,k) .lt. 32760 .and.
 2         abs(wcount(i,k)-iwmean) .le. 3 ) then
 wmean(k)=wmean(k)+wcount(i,k)
 numw=numw+1
 endif
 enddo !i=9,56
 if (nums .gt. 0) then
 smean(k)= smean(k)/float(nums)
 else
 print *,'nums=',nums
 irfail=1
 return
 endif
 if (numw .gt. 0) then


                                M-11       NOAA POD Guide - Jan. 2002 Revision11
 wmean(k) = wmean(k)/float(numw)
 else
 print *,'numw',numw
 irfail=1
 return
 endif
C! Here if too many spots are thrown away, add a flag showing
C! that calibration coefficients may be suspicious
 if (nums .le. 41 .or. numw .le. 41) then
 print*,'Too many spots are thrown away during calibration!!'
 do jl=1,40
 do js=1,56
 if(iii .eq. 1) then
 hirsdat(33,js,jl)=-1.0
 else
 hirsdat(33,js,jl)=-2.0
 endif
 enddo
 enddo
 endif
 140    continue !k=1,19
C! Calculate slope and intercept based on above results
 do k=1,19
 if((smean(k)-wmean(k)) .gt. 0.1) then
 nslope(iii,k)= (0.0 - prtrad(k))/ (smean(k) - wmean(k))
 nintcpt(iii,k)= 0.0 - nslope(iii,k)*smean(k)
C!       print *,'slope&amp;intcpt', k, nslope(iii,k),nintcpt(iii,k)
 else
 print *,'Sth wrong with warm BB counts or space-view counts!'
 irfail=1
 return
 endif
 enddo
C! Now predict the slope and intercept from instrument temperatures
and
C! get the differences between calculated and predicted coefficients
 do i=1,8
 if(winst(i) .gt. 0 .and. winst(i) .lt. 32760 .and.
 2 sinst(i) .gt. 0 .and. sinst(i) .lt. 32760) then
 ainst(i)=(winst(i)+sinst(i))/2.0
 else
 print *,'wsinst',winst(i),sinst(i)
 print *,'Sth wrong with instrument temperatures!'
 irfail=1
 return
 endif
 enddo
 do 150 k=1,19
C! slope
 pslope(iii,k)=0
 do j=1,8
 pslope(iii,k)=pslope(iii,k)+ coslope(j+1,k)*ainst(j)
 enddo
 pslope(iii,k)=pslope(iii,k)+coslope(1,k)
C!       print *,'pslope',pslope(iii,k)
 difslope(iii,k)=(nslope(iii,k)-pslope(iii,k))
C! intercept


                               M-12       NOAA POD Guide - Jan. 2002 Revision12
 pintcpt(iii,k)=0
 do j=1,8
 pintcpt(iii,k)= pintcpt(iii,k)+cointcpt(j+1,k)*ainst(j)
 enddo
 pintcpt(iii,k) = pintcpt(iii,k)+ cointcpt(1,k)
C!      print *,'pintcpt',pintcpt(iii,k)
 difintcpt(iii,k)=(nintcpt(iii,k)-pintcpt(iii,k))
 150 continue
 100 continue
C! End of calculate calibration at two ends of the Superswath R!C
C! Now get the calibration for all the scanlines
C! First move the cali from 2 to 41
 do k=1,19
 pslope(41,k) = pslope(2,k)
 pintcpt(41,k) = pintcpt(2,k)
 enddo
 do 160 is=4,40     ! all 37 earth-view scans
 do i=1,2128
 onehir(i)=suphirs(i,is)
 enddo
C! instrument temp count
 do it=1,8
 sinst(it)=onehir(484 + (62*22)+it)
C!          print *,'sinst',it, sinst(it)
 if(sinst(it) .lt. 0 .or. sinst(it) .gt. 32760) then
 print *,'Something wrong with sinst! Calibration coefficients for
 2                this scan will be zero!'
 goto 160
 endif
 enddo    !it=1,8
 do k=1,19
C! slope
 pslope(is,k)=0.0
 do j=1,8
 pslope(is,k)=pslope(is,k)+ coslope(j+1,k)*sinst(j)
 enddo
 pslope(is,k)=pslope(is,k)+coslope(1,k)
C! do some adjustment according to the difference at two ends
 pslope(is,k)=pslope(is,k)+difslope(1,k)
 pslope(is,k)=pslope(is,k)+(difslope(2,k)-difslope(1,k))
 . *((is-2)/40.0)
C! intercept
 pintcpt(is,k)=0.0
 do j=1,8
 pintcpt(is,k)= pintcpt(is,k)+cointcpt(j+1,k)*sinst(j)
 enddo
 pintcpt(is,k) = pintcpt(is,k)+ cointcpt(1,k)
C! do some adjustment according to the difference at two ends
 pintcpt(is,k)=pintcpt(is,k)+difintcpt(1,k)
 pintcpt(is,k)=pintcpt(is,k)+(difintcpt(2,k)-difintcpt(1,k))
 . *((is-2)/40.0)
C!      print *,pslope(is,k),pintcpt(is,k)
 enddo ! k=1,19
 160 continue
C! Fill the other ends scans
 do k=1,19
 do is=2,3


                               M-13       NOAA POD Guide - Jan. 2002 Revision13
 pslope(is,k)=pslope(1,k)
 pintcpt(is,k)=pintcpt(1,k)
 enddo
 do is=42,43
 pslope(is,k)=pslope(41,k)
 pintcpt(is,k)=pintcpt(41,k)
 enddo
 enddo
 end
C****************** end of calibration***************************



  function brightn(r,k)
C! changed for only converting NOAA-12 radiances to brightness
temperature, not adjusted.
c
c**********************************************************************
*
c
c    name- bright
c
c    language- forthxp     type- function
c
c    version-1.1     date- 9/15/77   programmer- fu, c.c.
c
c    function- converts radiance(mw/(m*m*sr/cm)) to brightness
c    temperature (K).
c
c    parameters-
c       variable                 type i/o function
c       --------                 ---- --- --------
c       r                        r*4 i    radiance
c       k                        i*4 i    channel number
c
c    key local parameters-
c       variable                 type function
c       --------                 ---- --------
c       bndcor(2,27)         r*4   band correction coefficients
c       fk1(27)                  r*4   =2*h*c*c*v*v*v
c       fk2(27)                  r*4   =h*c*v/b, where
c                                      v=wave number of a channel
c                                      c=velocity of light
c                                      h=planck constant
c                                      b=boltzmann constant
c
c    subprograms called - none
c
c    restrictions- input radiance should be screened before calling this
routine
c
c    common areas- procfl
c
c**********************************************************************
*
c----------------------------------------------------------------------
c


                                M-14       NOAA POD Guide - Jan. 2002 Revision14
c                       *** common procfl ***
c
c      common -procfl date -01/13/78 programmer - m. chalfant (ness)
c      function - transfers first group coefficients from cdb.
c      used by - limb,msucof,co2vtc,bright,cldcof,parmrd,ozcon,
c                 co2,h2o,ssucof,ozcof,interp,tranh,ozconv,trnh2o,planck,
c                 lmcorm,lmcorh,lmcors,co2ztc,ssuvtc,ssuztc,tmsu1,antmsx,
c                 regabs,msulbl,msureg,msuver,h2oreg,tropo,hirrad,oztau,
c                 co2tau,ssutau,trncon,radex,ssurad,chkhse,rd6a6b,cprtlo,
c                 cprthi,cprwv,fndssu,cprttp,cprpwv,storad,$tprps,bright
c                 comlnk,getcdb,gtcalh,gtcalm,gtcals,gthir,hircal,hirlim
c                 hir8lm,lstsqs,msucal,msulim,obrej,plank,readlm,print
c
c      real*4 ssulc(7,3,4,2),wvno(27),bandw(27),bndcor(2,27),
c     1 fk1(27),fk2(27),pret(40),hight,ssuscl(3),ssufug(9,3),
c     2 sigman(27),sigpro(27),gamt(27),asmsu(4,11),slope(6),
c     3 cept(6),fax(27),dum1(462)
c      integer*4 mvmsuo(27),mvsclr(27),mvmsul(27),mvs3l(27),mvs3o(27),
c     1 mvshir(27),mvshot(27),mvshi3(27),mvshic(27),msuhi(27),
c     2 ifgmvs,ishan(2,3),iprofl(200),nlevs,nwlevs,nhatm,nmatm,nhc,nmc,
c     3 nsc,norej(100)
c
c      common / procfl / ssulc,wvno,bandw,bndcor,fk1,fk2,pret,hight,
c     1 ssuscl,ssufug,sigman,sigpro,gamt,asmsu,slope,cept,fax,dum1,
c     2 mvmsuo,mvsclr,mvmsul,mvs3l,mvs3o,mvshir,mvshot,mvshi3,mvshic,
c     3 msuhi,ifgmvs,ishan,iprofl,nlevs,nwlevs,nhatm,nmatm,
c     4 nhc,nmc,nsc,norej
c
C!       include '../tovsoper/common/procfl.cmn1'
  real*4 waven(20)
  data waven/
  1 667.58,680.18,690.01,704.22,716.32,732.81,751.92,900.45,
  2 1026.66,1223.44,1368.68,1478.59,2190.37,2210.51,2236.62,
  3 2267.62,2361.64,2514.68,2653.48,14453.14 /
  c1=1.1910659E-5
  c2=1.438833
  wv=waven(k)
  expn=c1*wv*wv*wv/r+1.
  brightn=c2*wv/alog(expn)
  return
  end


 subroutine gethirs
C!
C! ***This version is for big endian platforms!!!
C! If used on little endian machine, need some switch on
C! variables associated with equivalence.
C*******************************************************************
C!    This subroutine calculates the HIRS BT for
C!    one superswath of data                        010912
C!    called by:   tvoprn.f, hirsbt.f
C!    modified, add some check                       010918
C!    modified for deal with 40 line superswath      011003
C!    Add some filter for space &amp; warm BD count data 011018
C!    Add channel 20 into process ans hirsdat        011023
C!    Change to handle bad superswath, let irfail=1 return 011101


                                 M-15       NOAA POD Guide - Jan. 2002 Revision15
C!      modified the adjustment with calculated coefficients 38-40
C!
C*******************************************************************
c***************************************************************
c    key local parameters-
c        variable             type       function
c        --------             ----       --------
c       band,bandc            real        Temperature correction coeff
c                                          the attached is NOAA12's
c         iord                int*2       The order of channels in Level
1b data
c          mfq                logical*1   Quality info of spot data
c         onehir              int*2       One scanline of 1b data
c       mclcf,nrmcf           int*2       Original calibration info saved
in Level 1b data
c       clcfh,rmcfh           real*4      Calibration coefficient from
mclcf,nrmcf
c        nflags               int*4       Scan quality flag
c       pslope, pintcpt       real*4      New calibration coeff for a
superswath
c
c***************************************************************
c*
  include 'superdata.cmn'
  include 'toohi.cmn'
  real*4 band(38),bandc(2,19)
  integer*2 iord(20)
  integer*2 nfl(2)
  logical*1 mfq(56)
  integer*4 jyr,jday,jhr,jmn,jsec,msec,nflags
  integer*2 onehir(2128)
  integer*4 mclcf(3,20),nrmcf(3,20)
  real*4 clcfh(3,20),rmcfh(3,20)
  real*4 pslope(43,19),pintcpt(43,19)
  real*4 pslp,picpt
  equivalence (nflags,nfl(1)),(mfq(1),onehir(1891))
  real*4 scale(3)
  data scale/4.194304e6,1.0737418e9,1.7592186e13/
  equivalence (mclcf(1,1),onehir(129)),(nrmcf(1,1),onehir(249))
  data iord/1,3,4,6,16,15,10,11,20,13,8,18,5,14,17,19,2,7,9,12/
  data band/
  1   0.007,0.99996 , 0.007,0.99995 , 0.019,0.99989 , 0.026,0.99988,
  2   0.021,0.99990 , 0.140,0.99964 , 0.058,0.99982 , 0.358,0.99940,
  3   0.181,0.99985 , 0.377,0.99975 , 0.175,0.99992 , 0.265,0.99863,
  4   0.078,1.00042 , 0.017,0.99995 , -0.023,0.99950 ,0.021,0.99995,
  5   0.022,0.99997 , 0.058,0.99992 , 0.344,0.99950 /
C! first get the calibration *********************************
  call newhirscali(pslope,pintcpt)
C! init the output array of HIRS data
  do k=1,40
  do j=1,56
  do i=1,35
  hirsdat(i,j,k)=-9999.9
  enddo
  hirsdat(1,j,k)=-1.0    !flags
  hirsdat(33,j,k)=1.0    !Cali flags
  enddo


                                 M-16       NOAA POD Guide - Jan. 2002 Revision16
  enddo
C! The temp correction coefficients
  do k=1,19
  bandc(1,k)=band((k-1)*2+1)
  bandc(2,k)=band(k*2)
  enddo
C!        print *,'bandc=',bandc(1,k),bandc(2,k)
  do 120 is=1,40          !40 scanlines
  do i=1,2128
  onehir(i)=suphirs(i,is)
  enddo
C! nflags ***if little endian switch 1 &amp; 2
  nfl(1)=onehir(5)
  nfl(2)=onehir(6)
C! first check the scan quality
  if(btest(nflags,31)) goto 120
  call tme1b(onehir(2),onehir(3),onehir(4),jyr,jday,jhr,
  .             jmn,jsec,msec)
C!        print *,'hirs time',jhr,jmn,jsec
C! pull the original calibration info out of the dataset
C! If little endian platform, do switching bytes
C!        do ik=1,180
C!           ntrans=onehir(8+ik*2)
C!           onehir(8+ik*2)=onehir(8+ik*2-1)
C!           onehir(8+ik*2-1)=ntrans
C!        enddo
C!        print *, 'cali info from data:'
  do j=1,20
c...     find the corresponding radiometric channel number
  k=iord(j)
  do im=1,3
  rmcfh(im,j)=nrmcf(im,k)/scale(im)
  enddo
C!        print*,(rmcfh(im,j),im=1,3)
  enddo
  do j=1,20
  k=iord(j)
  do im=1,3
  clcfh(im,j)=mclcf(im,k)/scale(4-im)
  enddo
C!        PRINT *,(clcfh(im,j),im=1,3)
  enddo
C! Since we only need ch20's info, ignore the correction of
C! calibration for chan 1&amp;2
C!
c =====================================================
c... loop thru 56 spots in HIRS line
c       for each spot check for mirror sequence error,
c       then loop through 20 channels and extract data.
c       convert the data to radiances and then to temps.
c =====================================================
  do 110 i=1,56
c... check mirror sequence error flag
  imfq=mfq(i)
  if (btest(imfq,2)) go to 90
c...     loop thru 20 channels for each spot
  do 80 k=1,19


                                M-17       NOAA POD Guide - Jan. 2002 Revision17
c...     find corresponding radiometric channel number
  m=iord(k)
  j=484+(i-1)*22+m
c... check for missing data
  if (onehir(j).eq.ifill) go to 90
c... calculate radiance
  c=onehir(j)
  pslp=pslope(is,k)
  picpt=pintcpt(is,k)
C!        print *,'slope&amp;intecept', is, k,pslp,picpt
  r=c*pslp+picpt
  if (is .eq. 1) then
  temp=r    ! save radiance instead of BT for space view
  go to 80
  endif
C!        if (is .gt. 3) print *, 'is,k,r',is,k,r
  if (r .le. 0. ) go to 90
  temp=brightn(r,k)
  temp =(temp-bandc(1,k))/bandc(2,k)
C!
C!        if (is .gt. 3) print *, 'BT from HIRS:',temp
C! check the bt with limits
  if(temp.lt.tooloh(k).or.temp.gt.toohih(k)) go to 90
C!      assign temperature to the output array
  80    hirsdat(8+k,i,is)=temp
C! ADD channel 20's processing here, use original calibration data
C! calculate chan 20 albedo
  m=iord(20)
  j=484+(i-1)*22+m
c... check for missing data
  if (onehir(j).eq.ifill) go to 110 !bad of ch20 will not affect other
channel
c... calculate radiance
  cc=onehir(j)
C!        print *, 'chan20 cc',i,cc
  c=rmcfh(1,20)+cc*(rmcfh(2,20)+cc*rmcfh(3,20))
  r=c*(clcfh(1,20)*c+clcfh(2,20))+clcfh(3,20)
!        print *, 'chan20 r',i,r,clcfh(1,20),clcfh(2,20),clcfh(3,20)
  if (r.lt.0.) r=0.
  hirsdat(8+20,i,is)=r
CCCCC ch20 added
C! assign different flags according to view
  if( is .eq. 1) then
  hirsdat(1,i,is)=2.0
  else if( is .eq. 2) then
  hirsdat(1,i,is)=3.0
  else if( is .eq. 3) then
  hirsdat(1,i,is)=4.0
  else
  hirsdat(1,i,is)=1.0
  endif
  hirsdat(2,i,is)=onehir(369+i*2)/128.    !lat
  hirsdat(3,i,is)=onehir(370+i*2)/128.    !lon
  hirsdat(4,i,is)=jyr                     !yrar
  hirsdat(5,i,is)=jday                    !day
  hirsdat(6,i,is)=msec                    !utc time
  hirsdat(7,i,is)=onehir(369)        !height


                                M-18       NOAA POD Guide - Jan. 2002 Revision18
 hirsdat(8,i,is)=onehir(370)/128. !local zenith angle
 goto 110
 90    do k=1,20  ! if a channel is bad, every channel bad, including
previous
 hirsdat(8+k,i,is)=-9999.0
 enddo
 110 continue
 120 continue
C! may do some output here?
 end


subroutine i2move(target,len,source)
 integer*2 target(len),source(len)
 do 10 i=1,len
 target(i) = source(i)
 10 continue
 return
 end


 subroutine rdhdr(insdd,idtatp,len1b,numsk,numdg,iendtm,insprt,
 1       satid)
c
c**********************************************************************
c
c   name- rdhdr                           expires- 12/31/99
c
c   language- fortran      type- subroutine
c
c   version- 1.0     date- 11/22/82   programmer- frank carr (sasc)
c
c   function-*$sd30fc* This subroutine will read the HIRS, MSU, and SSU
c         Level 1b dataset header records. It will check the header
record
c         length, date, data type, and satellite id. If any of the
checks
c         fail processing is returned to gthrd with iconfg set to less
c         than 100. This will eventually lead to a stop 4 execution
c         terminate in the preprocessor.    If all of the checks pass,
several
c         data items from header are passed to the common area headrc.
c
c   parameters-
c       variable                type i/o function
c       --------                ---- --- --------
c       insdd                   i*4 i    the instrument 1b dataset
ddname
c       idtatype                i*2 i    the instrument/satellite data
c                                        type. hirs = 5. msu = 6. ssu =
7
c       len1b                   i*2 i    the length of the 1b dataset
c                                        header record
c       numsc                   i*2 o    number of scan lines
c       numdg                   i*2 o    number of data gaps
c       iedtim                  i*2 o    the ending time of the header
c                                        record


                                M-19       NOAA POD Guide - Jan. 2002 Revision19
c       insprt                  l*4 i     the dataset name to be printed
c                                         for error messages
c       iextim                  i*4 i     the beginning execution time
c                                         for mstat texec
c       icktim                  i*4 i     the check time for a current
c                                         header record
c
c    files-
c       dsn or descriptive title i/o unit functional description
c       ------------------------ --- ---- ----------------------
c       (dynamically allocated)    i         HIRS 1b dataset
c       (dynamically allocated)    i         MSU 1b dataset
c       (dynamically allocated)    i         SSU 1b dataset
c
c    key local parameters-
c       variable                type function
c       --------                ---- --------
c       hdrbuf(2127)            i*2    buffer for storage of header
record
c       len                     i*2    the length returned from ffget
c       idate1,idate2,idate3    i*2    the 6 byte date from the header
c                                      record
c       formhd                  i*2    the format of the date to be
c                                      supplied to clue routine urdate
c       mask1                   i*2    mask used to find instrument id
c       numck                   i*2    number of scan lines in dataset
c       numdg                   i*2    number of data gaps in dataset
c       iendtm                  i*2    the ending time from the dataset
c                                      header
c       iyr                     i*4    the year from tme1b
c       idy,ihr                 i*4    the day and hour of day from tme1b
c       ijuldt                  i*4    the julian date obtained by
c                                      modifying the dates returned from
c                                      tme1b
c       ichrdy(37)              i*4    the various form of the Christian
c                                      day returned from urdate
c       irc                     i*4    the return code from urdate
c       ihdtm                   i*4    the hour date and time of the
c                                      header record
c
c    subprograms called- urdate,tme1b,fmove,frwnd
c
c    exit states- returns to gthrd
c
c    common areas- conflg,inbuf,headrc,mstat
c
c    block datas- units,printc
c
c**********************************************************************
c
c      rdhdr     version 1.0 fc    begun 11/22/82 completed 12/20/82
cllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllll
  logical*4 insprt
  integer*4 insdd,iyr,idy,ihr
cl       integer*4 insdd(2),iyr,idy,ihr,icktim,iextim
  integer*4 ihdtm,len1b,ijuldt
  integer*4 jstat


                                 M-20       NOAA POD Guide - Jan. 2002 Revision20
integer*2 hdrbuf(2128),idate1,idate2,idate3,idtatp
integer*2 mask1/'Z00F0'/,numsk,numdg,iendtm(3),satid
c
c*** initialize variables ***
c
  numsk = 0
  numdg = 0
  iendtm(1) = 0
  iendtm(2) = 0
  iendtm(3) = 0
c
  print *,'before reading....'
  read(insdd,rec=1,iostat=jstat) hdrbuf
cl        print *, hdrbuf
C!        print *,'head info'
C!        print *,hdrbuf(0),hdrbuf(1),hdrbuf(2)
cllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllll
  call i2move(idate1,1,hdrbuf(2))
  call i2move(idate2,1,hdrbuf(3))
  call i2move(idate3,1,hdrbuf(4))
cl
cl        call i2move(idate1,2,hdrbuf(2))
cl        call i2move(idate2,2,hdrbuf(3))
cl        call i2move(idate3,2,hdrbuf(4))
c
c*** obtain the time from the header from subroutine tme1b ***
c*** then convert this date into a julian date, then to a ***
c*** Christian date.                                         ***
c
  call tme1b(idate1,idate2,idate3,iyr,idy,ihr,imn,isec,msec)
  print *,'HEAD time'
  print *,iyr,idy,ihr,imn,isec,msec
c        pause
  ijuldt = (iyr*1000) + idy
  ihdtm = (ijuldt*100) + ihr
C!        satid = hdrbuf(1)/256
c
c
  50 satid = hdrbuf(1)/256
  100 return
  end
  subroutine readlm
c
c**********************************************************************
c
c     name- readlm
c
c     language- fortran     type- subroutine
c
c     version- 1.0    date- 06/13/80   programmer- domm
c     version- 2.0    date- 03/01/83   programmer- frank carr (sasc)
c
c     function- read allowed temperature limits for HIRS, MSU, and
c               SSU and convert to radiance limits
c
c     files-
c        dsn or descriptive title i/o unit functional description


                                M-21       NOAA POD Guide - Jan. 2002 Revision21
c        ------------------------ --- ---- ----------------------
c        nss.dpss.tovs.data(prelm i       37 raw temperature limits for
c                                             input to preprocessor
c
c    key local parameters-
c        variable                 type function
c        --------                 ---- --------
c        ifi                      i*4    fortran file unit number
c        toohih                   r*4    hirs upper radiance limits
c        tooloh                   r*4    hirs lower radiance limits
c        toohim                   r*4    msu upper radiance limits
c        toolom                   r*4    msu lower radiance limits
c        toohis                   r*4    ssu upper radiance limits
c        toolos                   r*4    ssu lower radiance limits
c        i                        i*4    concatonated channel number
c        k                        i*4    channel number
c
c    common areas- toohi,procfl
c
c**********************************************************************
c
c      readlm1 version 2.0 fc       begun 03/11/83 completed 03/11/83
c
c *** first read the upper and lower limits for ***
c *** the HIRS, MSU and SSU temperature limits ***
c
  include 'toohi.cmn'
  ifi=37
cl
  open(ifi, file='PRELMS3.dat', status='old')
cl
  read (ifi,1010) (toohih(k),k=1,20)
  read (ifi,1010) (tooloh(k),k=1,20)
  read (ifi,1020) (toohim(k),k=1,4)
  read (ifi,1020) (toolom(k),k=1,4)
  read (ifi,1030) (toohis(k),k=1,3)
  read (ifi,1030) (toolos(k),k=1,3)
c        write (*,1010) (toohih(k),k=1,20)
c        write (*,1010) (tooloh(k),k=1,20)
c        write (*,1020) (toohim(k),k=1,4)
c        write (*,1020) (toolom(k),k=1,4)
c        write (*,1030) (toohis(k),k=1,3)
c        write (*,1030) (toolos(k),k=1,3)
c
c *** now convert the temperature limits to radiances ***
c *** channel 20 need not be converted as the limits ***
c ***                     are 0,0                         ***
cl         do 1000 k=1,19
cl         toohih(k)=planck(toohih(k),k)
cl         tooloh(k)=planck(tooloh(k),k)
cl         if (k.gt.4) go to 1000
cl         i=k+20
cl         toohim(k)=planck(toohim(k),i)
cl         toolom(k)=planck(toolom(k),i)
cl         if (k.gt.3) go to 1000
cl         i=k+24
cl         toohis(k)=planck(toohis(k),i)


                                M-22       NOAA POD Guide - Jan. 2002 Revision22
cl       toolos(k)=planck(toolos(k),i)
cl 1000 continue
c
  return
c
  1010 format (14(f4.0,1x),/,6(f4.0,1x))
  1020 format (4(f4.0,1x))
  1030 format (3(f4.0,1x))
  end



 subroutine tme1b(icode1,icode2,icode3,iyr,idy,ihr,imn,
 .   isec,nsec)
c
c**********************************************************************
c
c    name- tme1b                            expires- 12/31/99
c
c    language- fortran      type- subroutine
c
c    version- 1.0    date- 03/30/83     programmer- alice filemyr bell
c    version- 2.o    date- 06/28/87     programmer- s. chattopadhyay
c
c    function-*$sd30fc* repack time from 1b dataset format.
c
c    This program was transferred from tovs lib. to klmv lib. by
c    s. k. chattopadhyay on 06/28/87. This program is used without
c    any modification.
c
c    parameters-
c       variable                 type i/o function
c       --------                 ---- --- --------
c       icode1,icode2,icode3     i*4 i     the first three words
c                                          containing the time in Level 1b
c                                          dataset format
c       iyr                      i*4 o     year
c       idy                      i*4 o     day
c       ihr                      o    o    hour
c       imn                      i*4 o     minutes
c       sec                      i*4 o     seconds
c
c    common areas- (none)
c
c    block data- (none)
c
c**********************************************************************
cl
  integer*2 icode1,icode2,icode3,idum(2),it(2)
  integer*4 itemp,isec,iyr,mnday
  equivalence (msec,idum(1))
  equivalence (itemp,it(1))
  itemp=0
  idum(1)=icode2
  idum(2)=icode3
  mnday=msec/60000
  idyyr=icode1


                                 M-23       NOAA POD Guide - Jan. 2002 Revision23
  it(2)=icode1
  iyr = ishft(itemp,-9)
  it(2)=icode1
  itemp =ishft(itemp,23)
  idy = ishft(itemp,-23)
  nsec = msec
c      it(2) = 0
c      it(1) = icode1
c      iyr = ishft(itemp, -9)
c      it(1) = icode1
c      itemp = ishft(itemp, 7)
c      idy = ishft(itemp, -7)
  ihr=msec/3600000
  msec=msec-ihr*3600000
  imn=msec/60000
  msec=msec-imn*60000
cl       sec=float(msec)/1000.0
  isec=(msec)/1000
cl
cl        call ymdjdt(iyr,imo,idy)
cl        iyrmo=iyr*100 + imo
cl        idyhr=idy*100 + ihr
cl        imnsc=imn*100 + isec
cl        print *, 'iyrmo,idyhr,imnsc,mnday',iyrmo,idyhr,imnsc,mnday
cl        julmin=mnday+(idy-1)*minday
cl
  return
  end




                                 M-24       NOAA POD Guide - Jan. 2002 Revision24

				
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