Leicester by cuiliqing

VIEWS: 4 PAGES: 7

									           Comparison of AATSR SST with
                  other sensors


                                           David Ridley
                                        Marianne Edwards
                                      Space Research Centre
                                       University of Leicester




Validation Workshop, 9-13th December 2002, ESRIN                 Page 1
                         Comparison with global datasets

 Comparison of global monthly mean AATSR SST data with:-
      •   ATSR-2
      •   AVHRR
      •   MODIS
      •   ECMWF
      •   TMI
 To date, comparisons performed between AATSR data and MODIS,
  ECMWF and TMI for September 2002
 Data compared are monthly means, at half degree resolution
 AATSR data used: spatially averaged product, dual view SST
  retrieval, all available data


Validation Workshop, 9-13th December 2002, ESRIN                 Page 2
                                              Methodology
   Difference images produced to find areas of discrepancy for more
    detailed analysis.
   Time series analysis.




Validation Workshop, 9-13th December 2002, ESRIN                       Page 3
                                                            AATSR vs ECMWF
                                                               Sept 2002




                                                            ECMWF: 2.5 degree

    Mean global difference: -0.05 deg K
    Mean absolute difference: 0.88 deg K
    Standard deviation: 1.43 deg K
    Tropical region (+/- 30 degrees)
      • Mean difference: -0.40 deg K
      • Standard deviation: 0.88 deg K
      • Percentage of values between +/- 0.6 deg K: 54.82

    Validation Workshop, 9-13th December 2002, ESRIN                            Page 4
                                                           AATSR vs TMI
                                                             Sept 2002




                                                           TMI data: 0.25 degree
                                                           Binned to half degree
                                                              for comparison

   Mean global difference: -0.38 deg K (TMI warmer)
   Mean absolute difference: 0.50 deg K
   Standard deviation: 0.55 deg K
   Tropical region (+/- 30 degrees)
     • Mean difference: -0.42 deg K
     • Standard deviation: 0.50 deg K
     • Percentage of values between +/- 0.6 deg K: 68.48
    Validation Workshop, 9-13th December 2002, ESRIN                     Page 5
                                                            AATSR vs MODIS
                                                               Sept 2002




                                                                   MODIS: 36km,
                                                            SST from 11 micron day/night

 Mean global difference: -0.41deg K (MODIS warmer)
 Standard deviation: 0.75 deg K
 Tropical region (+/- 30 degrees)
    •   Mean difference: -0.41 deg K
    •   Standard deviation: 0.51 deg K
    •   Percentage of values between +/- 0.6 deg K: 65.63


  Validation Workshop, 9-13th December 2002, ESRIN                          Page 6
                                             Conclusions

 Preliminary results - comparisons performed for AATSR data
    and SST from ECMWF analyses, MODIS and TMI data, for
    September 2002
   Difficult to see patterns with one month’s data. More data and
    processing needed, including comparisons with AVHRR and
    ATSR-2.
   Further investigations needed.
    • How accurate are TMI and MODIS against buoy data?
    • Spot checks using precision radiometers




Validation Workshop, 9-13th December 2002, ESRIN              Page 7

								
To top