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					IASI Technical Expertise Center : IASI tuning and
            performance monitoring

                           Vincent Lonjou, Laurence Buffet, Jordi Chinaud,
                           Carole Larigauderie, Frédérique Meunier and
                           Eric Péquignot
                                                                      Outline

               1. Introduction
               2. Technical Expertise Center overview
                    •     Role
                    •     Organization
                    •     Interfaces
               3. IASI performances
                    •     Radiometric performances, decontamination
                    •     Intercalibration
               4. Main IASI results
                    •     Meteorology
                    •     Atmospheric chemistry
               5. Conclusion



Space OPS 2010 – Vincent Lonjou - CNES
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                                            1. Introduction



               ■ IASI
                    Interféromètre Atmosphérique de Sondage Infrarouge
                    Infra Red Atmospheric Sounder
                    CNES-EUMETSAT cooperation
                         Thales Alenia Space as prime contractor


               ■ Satellite : METOP-A (launched in 2006)
                    Polar orbiting satellite (European Polar System - EPS)
                    Operational meteorology + Science
                    Operated by EUMETSAT
                    METOP-B (2012) and METOP-C (2016)




Space OPS 2010 – Vincent Lonjou - CNES
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                                         1. Introduction

                                                           IASI scientific objectives



          ■ IASI has been designed for operational meteorological soundings
              very high level of accuracy, stringent specifications : 1K for 1 km on
               temperature and 10 % for humidity
              => medium range weather forecast

          ■ Trace gases column amount (CO, CH4, N2O) are retrieved with an
           accuracy better than 10% and 5 % for Ozone

          ■ 2nd IASI International conference, Annecy, France, January 25-29, 2010
                About 200 attendees




Space OPS 2010 – Vincent Lonjou - CNES
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                                           1. Introduction

                                                                        IASI instrument

  IASI is an infra-red atmospheric sounder based on a Michelson interferometer




       IASI onboard METOP

                                     1.3 millions of spectra / day !!
Space OPS 2010 – Vincent Lonjou - CNES
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                                               1. Introduction

                                                                 IASI instrument

   Sounder
• Scan Rate                        8 secs
• Swath                            ± 48.98° 1066 km
• Spectral Range                   645=>2760 cm-1 (3 bands)
• Spectral Range                   3.62 - 15.5 um
• Spectral Sampling                0.25 cm-1 (8460 channels)


• Lifetime                         5 years


• Pixel IFOV                       0.8225°
• IFOV size at Nadir               12 km


+ Integrated Imager Subsystem (IIS)
• 64*64 pixels
• Co-registration IASI with AVHRR => geolocalization

Space OPS 2010 – Vincent Lonjou - CNES
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                                          1. Introduction

                                                                         CNES role in IASI

         ■ Technical oversight responsibility for the instruments up to their deliveries
          to EUMETSAT

         ■ On-board processing software (DPS)
               Developed and maintained by CNES
               Interferogram => spectrum
               Reduce data rate

         ■ Level 1 processing chain
               Maintained by CNES and operated by EUMETSAT
               Post-calibration necessary to reach the specifications and data quality

         ■ IASI Technical Expertise Center
                 Maintained and operated by CNES
                 Deployed at Toulouse Space Center
                 Monitor the instrument
                 Tune the instrument and level 1 processing chain
                 Maintain the on-board processing software and the L1 processing chain

Space OPS 2010 – Vincent Lonjou - CNES
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                                2. IASI Technical Expertise Center overview
                                                                           IASI system

                                         IASI Technical Expertise Center



      Software (DPS)                 L0 data              Software           L1 data
      Configurations                                      Configurations


                              Instrument                     Level 1 processing chain




Space OPS 2010 – Vincent Lonjou - CNES
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                                2. IASI Technical Expertise Center overview

                                                       IASI level 1 processing chain

        ■ L0 => L1: complex process, 3 steps

             1a : calibrated spectra        + interferometric axis position quality, …
             1b : rebinned spectra          + black-body temperature filtering quality,
                                             quality IIS,…
             1c : apodized spectra          + co-registration quality, …

                                Users

                                                           IASI Technical Expertise Center

             ENG : technological products (some spectra, image IIS, … L1)
             VER : verification product (raw data / on-board data samples, … L0)



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                                2. IASI Technical Expertise Center overview
                                                                                  Adaptation to mission phase




                                         TRANSFER OF TRAINING
 Commissioning phase                                                Routine phase                         Anomaly




                                                                                         SUPPORT
    • ~ 6 months                                                • unknown duration ??              • when ?
    • ~10 persons                                               • ~3-4 persons ?                   • tiger team (X persons ?)
          • experts                                                 • operators                    • on-demand experts
          • operators                                               • experts
    • specific tasks                                            • routine tasks
          • routine training                                    • reporting
    • routine specification



                                                                    • transfer of training
                                                                    • external operators (redundancy)
                 Flexibility                                        • support from experts
                                                                    • procedures
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                                2. IASI Technical Expertise Center overview
                                                                       Automatic processing

                                         Archiving system


                                                       Data base (catalog)



                                                  IASI-TEC                       IASI-TEC users
                              IASI                                               • Operators
                              data                                               • Experts
                                           Automatic processing

        EUMETCAST

                                           Data monitoring
                                           • performance monitoring
                                           • control panel



Space OPS 2010 – Vincent Lonjou - CNES
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                                2. IASI Technical Expertise Center overview

                                                                        Routine activities



                                                  ■ Daily monitoring
                                                      Instrument control panel
                                                      Operators
                                                      Check the general status of the instrument




                                                  ■ Manually run specific tasks
                                                        Related to relatively stable parameters
                                                        More complex => experts
         Instrument control panel                       Geometric performances
                                                        Ice contamination monitoring




Space OPS 2010 – Vincent Lonjou - CNES
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                                2. IASI Technical Expertise Center overview
                                                            Configuration deliveries




  Commissioning                  Routine phase
     phase                       (parameters related to instrument degradation/evolution)



Space OPS 2010 – Vincent Lonjou - CNES
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                                                 3. IASI performances
                                                                      General quality flag




                                      End of commissioning delivery
                 Anomaly ratio in %




     • More than 99% are good !!
     • Data rejection is mainly due to spikes (corrupted interferogram in the SAA)
Space OPS 2010 – Vincent Lonjou - CNES
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                                                                              3. IASI performances

                                                                Instrument anomalies since the end of commissioning

                                                                            15/05/2007
        30/10/2009                 09/12/2008
                                                                            SEU laser
        SEU CCM ALU                SET DPS Main

                                                            07/09/2009                           ■ Contribution of SEU anomalies to
                                                            SEU CCM ALU
                                                                                                   the instrument downtime was
                                                                                                   about 1% in 2007-2008 and about
                                                                                                   0.05% in 2008-2009.
                                      26/08/2009
                                      SEU DMC      09/02/2008
                                                                                                     On-board patch
                                   08/11/2007
                                   SEU DMC
                                                   SEU DPC 3B
                                                                                                     Procedure improvement
                                                   13/06/2007
                               21/07/2008          SEU DMC
                               SEU DPC 1A


                                                                                                 ■ CCM : Corner cube mechanism
                      01/11/2007     18/11/2007
                      SEU DPC 4A     SET DPS DMC


                                                                                                 ■ DMC : Data Management Control
                      SAA
                                                                          20/07/2007
                                                                          SEU DPC 3A
                                                                                                 ■ DPC : Data Processing Chain
          04/02/2008
          SEU CCM ALU                                                        29/12/2008
                                                                                                 ■ DPS : Data Processing Subsystem
                                                                             EQSOL double edac




    => “Metop/IASI revisited operations concept : several ways to minimize mission
    down time w.r.t. SEUs”, Buffet L. et al., presented by Montero D., these conference.
Space OPS 2010 – Vincent Lonjou - CNES
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                                         3. IASI performances
                                                     Radiometric performances




   Effect of ice contamination
   on cold optics




       Decontamination


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                                              3. IASI performances
                                                                         Decontamination

                                  Relative transmission @ 850 cm-1 = f(time)




                       • Second IASI decontamination on 2008/03/20
                           • take the opportunity of an anomaly with thermal control lost
                           • perfect recovery

Space OPS 2010 – Vincent Lonjou - CNES
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                                               3. IASI performances

                                                                   Next decontamination ?

                                         Relative transmission @ 850 cm-1 = f(time)




                                                                                Extrapolation
     Specification
     = 0.8


                             next decontamination is planned for end of 2010
                             operation request by IASI-TEC
Space OPS 2010 – Vincent Lonjou - CNES
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                                             3. IASI performances

                                                                                      Reporting

                 ■ Monthly report
                      CNES internal

                 ■ Quarterly report
                      Publicly available on IASI website ( http://smsc.cnes.fr/IASI/ )

                 ■ Mid-term review
                      at EUMETSAT together with CNES
                      EUMETSAT-CNES joint report

                 ■ Annual review
                      at CNES together with EUMETSAT
                      EUMETSAT-CNES joint report

                 ■ Regular CNES-EUMETSAT teleconferences



Space OPS 2010 – Vincent Lonjou - CNES
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                                                             3. IASI performances

                                                                            IASI/AIRS inter-comparison tool

              ■ Work in the frame of GSICS (Global Space-based Inter-Calibration System)
              ■ Extract CNO (Common Nadir Overpass) over IASI and AIRS
              ■ Draw differences between IASI and AIRS pseudo-channels



     IASI (red) and AIRS (black) pseudo-                     IASI-AIRS differences vs time                     IASI-AIRS differences vs brightness
            spectra (650- 850 cm-1)                                   channel 15                                    temperature (channel 26)


                                                                 North hemisphere
                                                                 South hemisphere                                        ~ 1/10 K
                                           Difference in K




                                                                                             Difference in K
                                                               Stable over time
          Wavenumbers (cm-1)                                          CNO date                                     Brightness temperature


Space OPS 2010 – Vincent Lonjou - CNES
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                                             4. Main IASI results

                                   IASI spectra assimilation impact on weather forecast




                                                     ■ IASI is the sounder that has the most
                                                      significant impact on weather forecast

                                                     ■ impact from IASI is equivalent to a single
                                                      Advanced Microwave Sounding Unit-A
                                                      (AMSU-A) combined with a single
                                                      Microwave Humidity Sounder (MHS)




                      From Hilton, F., et al., Q.J.R. Meteorol. Soc. 135: 495–505 (2009)

Space OPS 2010 – Vincent Lonjou - CNES
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                                             4. Main IASI results

                                                                       IASI data retrieval

                             First ammonia (NH3) world wide distribution




                           Lieven Clarisse et al., Nature Geoscience, 21/06/2009
Space OPS 2010 – Vincent Lonjou - CNES
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                                               5. Conclusion



              ■ IASI Technical Expertise Center
                   Keystone of IASI system
                   Regular and detailed monitoring of the instrument
                   Regular delivery of board and ground configurations


              ■ IASI status
                   Instrument is behaving very well
                   IASI major impact on weather forecast, and more generally science


              ■ IASI-2 on METOP-B planned for 2012
                   IASI-1 and IASI-2 in-flight at the same time
                   => intercalibration


Space OPS 2010 – Vincent Lonjou - CNES
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                                         BACKUP SLIDES




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                                                         24
                                                                                                                      QUESTIONS

       ■ Synchronization METOP-A / METOP-B
               The Metop-B orbit will be identical to Metop-A, but there will be a difference of 49 minutes between the 2 satellites. This implies a
               difference in ground track for each succeeding orbit, but the Metop-B ground track will repeat the exact Metop-A ground track after 12
               days; there are no differences in product accuracy or Earth coverage.



       ■ Activities planned in terms of IASI-1  IASI-2 intercalibration




Space OPS 2010 – Vincent Lonjou - CNES
                                                                                                                                                        25
                                                                              AIRS


        ■ Atmospheric Infrared Sounder, AIRS, onboard AQUA
        ■ Orbit
             438 miles (705.3km) polar, sun synchronous, 98.2+/- .1 degrees
              inclination, ascending node 1:30pm +/- 15 minutes, period 98.8 minutes



                                                       IR Spectral Coverage
                                                       •3.74 - 4.61 microns
                                                       •6.20 - 8.22 microns
                                                       •8.80 - 15.4 microns




Space OPS 2010 – Vincent Lonjou - CNES
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                 2. IASI Technical Expertise Center overview
                                                               IASI instrument
                                     USERS                     on-board METOP

         Interfaces
                                         L1, L2 data           Digital Processing Software
                                                               On-board configuration

IASI-TEC
•IASI monitoring
                               L0, L1, L1ENG
•Configuration generation      for instrument monitoring



         test configurations    Anomaly, change request
                                • Instrument
                                • Level 1 processing

IASI L1/PPF
Development version
                                Configuration delivery
                                • On-board processing
                                                               IASI L1/PPF
                                • level 1 processing           Operational version
Digital Processing Software
Development version             Software delivery
                                •L1/PPF
                                •Digital Processing Software

     IASI Expertise Center
       CNES, Toulouse                                               EUMETSAT
                                            3. IASI performances

                                                                  Spectral performances
               Interferometric axis position Y                   Interferometric axis position Z

                                                        0                               Specification
           0
                                                             Warning threshold
  radian




                                                     -4E-4

  -4E-4



                              Date                                               Date

                         Z
                                            => IASI optical axis is very stable over time
                                   Y
                                            => Mean values now are part of the level 1
                                            configuration (improve data availability)

               IASI focal plane
Space OPS 2010 – Vincent Lonjou - CNES
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                                              3. IASI performances
                                                             Geometric performances




                                                                                           Specification = 0.3
                                                                                   ~0.05

                            IIS
   AVHRR
   line          1          SN           30
                                                 => Observed variation along track ~0.05
                      Image AVHRR
                                                 AVHRR pixel (100m)
                     AVHRR column                => Geometric performances are very
                                                 stable
Space OPS 2010 – Vincent Lonjou - CNES
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