NOAA’s National Weather Service NDFD File Dissemination Services

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NOAA’s National Weather Service NDFD File Dissemination Services Powered By Docstoc
					NOAA’s
National Weather Service
NDFD File Dissemination Services

Allan Darling
Office of the CIO, Telecommunication Operations Center

National Digital Forecast Database Technical Workshop

November 2, 2006
  NDFD File Dissemination Services

   Where to find NDFD product files –
   Files are available via:
           ftp://tgftp.nws.noaa.gov
           http://weather.noaa.gov/pub
           ftp://ptgftp.nws.noaa.gov
           ftp://tgdata.nws.noaa.gov
           Access to ptgftp.nws.noaa.gov and tgdata.nws.noaa.gov are
           limited to SAS customers.
           See http://weather.gov/datamgmt/fos/fospage.html for more
           information about Server Access Services.


NDFD Technical Workshop 2006
  NDFD File Dissemination Services

  Where to find NDFD product files –
  On each server, NDFD data is found under the paths:
  /SL.us008001/ST.opnl/DF.gr2/DC.ndfd/...
  or
  /SL.us008001/ST.expr/DF.gr2/DC.ndfd/...

  The path indicates that the data is on the public NWSTG FTP server, is
  operational or experimental, is encoded in WMO GRIB Edition 2 format, and
  is all related to the NDFD data category.
  See http://www.nws.noaa.gov/datamgmt/filstnd.html for more information
  about the directory and file naming standards used on the NWSTG FTP and
  HTTP Servers

NDFD Technical Workshop 2006
  NDFD File Dissemination Services

   How files are named –
   Following the data format and category directories,
   the last directories and the file name specify:
   • the geographic area (/AR.aaaaaaaa)
   • the valid period (/VP.ddd-ddd)
   • the data subcategory (/ds.sssss)
   A list of all the NDFD Sectors (geographic areas) defined by lat/lon and
   grid points is available at:
   http://www.nws.noaa.gov/datamgmt/doc/ndfdelem.xls
   A list of data subcategories is available at:
   http://www.weather.gov/ndfd/resources/NDFD_element_status.pdf



NDFD Technical Workshop 2006
  NDFD File Dissemination Services

   How files are constructed –
   Files are comprised of:
   • A flag field separator block (option 2)
   • A super heading
   • One or more GRIB products each comprised of
       – A flag field separator block (option 2)
       – A WMO Heading
       – A GRIB product




NDFD Technical Workshop 2006
  NDFD File Dissemination Services

   A flag field separator block (option 2) is a file
   delimiter that provides the length of the product that
   follows it. The format is:

   ****nnnnnnnnnn****lf

   Where nnnnnnnnnn is the length of the product
   following the seperator, in bytes and lf is an ASCII
   line feed. See http://weather.gov/tg/fstandrd.html
   for more details.



NDFD Technical Workshop 2006
  NDFD File Dissemination Services

   What is a “super heading”?

   In order to aggregate forecast periods for one data
   subcategory and one sector, the “super heading”
   was developed.

   The super heading specifies the data subcategory
   in T2 and the geographic sector in A1. A2 and ii are
   fixed as “Z98” or “Z97”:

   NDFD Super Heading: YT2A1Z98 KWBN


NDFD Technical Workshop 2006
  NDFD File Dissemination Services

   How product headings are formed –

   Generic NDFD Heading: YT2A1A2ii KWBN
   T2 specified the data type (data subcategory)
   A1 specifies the geographic designator (NDFD sector)
   A2 and ii together specify the NDFD reference time (not represented in the
   directory or file names)


   The possible values for T2 , A1 , A2 , and ii and their meanings are
   specified on the NDFD WMO Heading Reference page at

   http://weather.gov/datamgmt/doc/ndfdref.html



NDFD Technical Workshop 2006
  NDFD File Dissemination Services

   How files are constructed –
   ****0004911342****
   YEUZ98 KWBN 301549
   ****0000266234****
   YEUB18 KWBN 301549
   GRIB..................7777
   ****0000018847****
   YEUB21 KWBN 301549
   GRIB.....................7777
   .
   .
   .
   ****0000018051****
   YEUE00 KWBN 301549
   GRIB.................7777


NDFD Technical Workshop 2006
  NDFD File Dissemination Services

   Where to find NDFD product files –
   Files are available via:
           ftp://tgftp.nws.noaa.gov
           http://weather.noaa.gov/pub
           ftp://ptgftp.nws.noaa.gov
           ftp://tgdata.nws.noaa.gov
           Access to ptgftp.nws.noaa.gov and tgdata.nws.noaa.gov are
           limited to SAS customers.
           See http://weather.gov/datamgmt/fos/fospage.html for more
           information about Server Access Services.


NDFD Technical Workshop 2006
  NDFD File Dissemination Services

   Legacy NWSTG file services:

   HTTP access via Internet –
            http://weather.noaa.gov (5 servers)
   FTP access via Internet –
            ftp://tgftp.nws.noaa.gov (4 servers)
   FTP access via dedicated communication
   paths –
           ftp://ptgftp.nws.noaa.gov (2) servers

NDFD Technical Workshop 2006
  NDFD File Dissemination Services

   Significant system upgrades as part of
   the Replacement NWSTG implementation,
   including:
    •   Linux servers
    •   Redundant, highly available NFS servers
    •   Network-based load balancing
    •   Gigabit Ethernet internal network
    •   Improved network devices




NDFD Technical Workshop 2006
  NDFD File Dissemination Services

   Replacement NWSTG file services:

   HTTP access via Internet –
            http://weather.noaa.gov (6 servers)
   FTP access via Internet –
            ftp://tgftp.nws.noaa.gov (5 servers)
   FTP and HTTP access via dedicated
   communication paths –
           ftp://tgdata.nws.noaa.gov (3 shared servers)
           http://tgdata.nws.noaa.gov (3 shared servers)

NDFD Technical Workshop 2006
  NDFD File Dissemination Services

   tgdata.nws.noaa.gov available for testing in the
   Replacement NWSTG since August
       – Supported operationally as of November 8, 2006

       – Four week overlap between startup of tgdata.nws.noaa.gov
         and shutdown of ptgftp.nws.noaa.gov


   weather.noaa.gov and tgftp.nws.noaa.gov still in
   Legacy NWSTG
       – Service will move (transparently) to the Replacement NWSTG
         by December 1




NDFD Technical Workshop 2006
  NDFD File Dissemination Services




                     Questions Now?




                     Questions Later? Allan.Darling@noaa.gov


NDFD Technical Workshop 2006
  NDFD File Dissemination Services




               Additional Information




NDFD Technical Workshop 2006
  NDFD File Dissemination Services
     Super heading flag field separator -
   ****0000149136****              ****0000149136****
   YGCZ98 KWBN 031906
   ****0000018449****              YGCZ98 KWBN 031906
   YGCB00 KWBN 031906
   GRIB..................7777
   ****0000018847****              149136 is the length, in
   YGCC00 KWBN 031906              bytes, of the super heading
   GRIB.....................7777
                                   and all the following groups
   .
                                   of flag field separators,
   .
                                   WMO headings, and GRIB
                                   products.
   .
   ****0000018051****
   YGCI00 KWBN 031906
   GRIB.................7777




NDFD Technical Workshop 2006
  NDFD File Dissemination Services
     “Regular” flag field separator -
   ****0000149136****              ****0000018449****
   YGCZ98 KWBN 031906
   ****0000018449****              YGCB00 KWBN 031906
   YGCB00 KWBN 031906              GRIB.............7777
   GRIB..................7777
   ****0000018847****
   YGCC00 KWBN 031906
   GRIB.....................7777   18449 is the length, in bytes,
   .                               of the single heading and
   .                               GRIB product.
   .
   ****0000018051****
   YGCI00 KWBN 031906
   GRIB.................7777




NDFD Technical Workshop 2006
  NDFD File Dissemination Services

   Online References

   NWSTG Data Management NDFD Reference -
   http://weather.gov/datamgmt/doc/ndfdindex.html
   Directory and File Naming Standards –
   http://weather.gov/datamgmt/filstnd.html
   Family of Services Main Page –
   http://weather.gov/datamgmt/fos/fosindex.html
   Gateway File Standards and Content Structures –
   http://weather.gov/tg/fstandrd.html


NDFD Technical Workshop 2006
  NDFD File Dissemination Services

   Backup NWSTG file services -
   Data access service backup will be split
       – Public Internet service will be provided at the Primary NWSTG
         and at NWS Central Region Headquarters
       – Non-public service will be provided at the Primary NWSTG and
         the Backup NWSTG
   Back-end NFS servers will be populated at the
   active NWSTG
       – Primary active: data copied to the backup NWSTG and CR HQ
       – Backup active: data copied to CR HQ




NDFD Technical Workshop 2006
  NDFD File Dissemination Services
          Access via Dedicated Communications




NDFD Technical Workshop 2006
  NDFD File Dissemination Services
                         Access via Internet




NDFD Technical Workshop 2006

				
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