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TH4-TO3_5-smos_in_flight.ppt

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TH4-TO3_5-smos_in_flight.ppt

  1. 1. SMOS IN FLIGHT SYSTEM PERFORMANCES ASSESSEMENT AVFETER 1 YEAR IN ORBIT F Cabot, A. AlBitar, , P. Richaume, Y.H. Kerr
  2. 2. Reprocessed Data Quality and Stability <ul><li>L1C assessment </li></ul><ul><ul><li>Geometry </li></ul></ul><ul><ul><li>Radiometric accuracy </li></ul></ul><ul><ul><li>Absolute accuracy </li></ul></ul><ul><ul><li>Repeat with new antenna model </li></ul></ul>Igarss '11 - Vancouver
  3. 3. Reprocessed L1C <ul><ul><li>The data analysed spans over 1 year of Data (2010) </li></ul></ul><ul><ul><ul><li>Madagascar geometry </li></ul></ul></ul><ul><ul><ul><li>Dome Concordia </li></ul></ul></ul><ul><ul><ul><ul><li>Radiometric accuracy </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Absolute brightness temperature accuracy </li></ul></ul></ul></ul><ul><ul><li>All data have now been processed up to level 2 (SM) and is also investigated over various validation sites </li></ul></ul><ul><ul><li> See Monday’s presentation </li></ul></ul>Igarss '11 - Vancouver
  4. 4. Geolocation assessment <ul><li>Method developped and validated before flight with simulated data </li></ul><ul><li>Simple model fit across sharp transition gives access to shift assessment. </li></ul><ul><li>Madagascar coastline selected: long linear coastline. </li></ul><ul><li>Additional checking being conducted using Earth Horizon ceossing the field of view during external calibration manoeuvre. </li></ul>Igarss '11 - Vancouver
  5. 5. Madagascar Coastline access Igarss '11 - Vancouver
  6. 6. Model fitting results Igarss '11 - Vancouver
  7. 7. Ascending - Descending <ul><li>Alternate passes are used to constrain geolocation matrix. </li></ul><ul><li>Depending on the position of the coast within the swath, this constrain can change. </li></ul>Igarss '11 - Vancouver
  8. 8. Temporal evolution of the geolocation over Madagascar <ul><li>Same technique used as during commissionning, gives less noisy results. </li></ul><ul><li>All products being processed with same BFP (and correctly applied) </li></ul><ul><li>std(Ascending) = 350m </li></ul><ul><li>std(Descending) = 460m </li></ul><ul><li>Trend is clearer than at the end of IOCP and slightly degrades final RMS </li></ul>Igarss '11 - Vancouver
  9. 9. Acquisitions over DomeC <ul><li>Selection of closest DGG node and extraction from L1C products. </li></ul>Igarss '11 - Vancouver
  10. 10. Radiometric Accuracy over Dome C <ul><li>Over 12 months of data, Dome C has been seen more than 200000 times in full pol, spanning the entire EAF Fov. </li></ul><ul><li>Assuming the target has not changed, we can compute radiometric accuracy as the standard deviation of measured brightness temperature within the FoV. </li></ul><ul><ul><ul><li>TX TY TX TY T3 T4 </li></ul></ul></ul><ul><ul><li>Estimated 2.5337 2.3503 4.1970 3.8349 2.8613 3.0761 </li></ul></ul><ul><ul><li>Computed 2.1181 2.1696 3.4531 3.4724 2.9358 2.9358 </li></ul></ul>Igarss '11 - Vancouver
  11. 11. Radiometric Accuracy over Dome C <ul><li>T3 and T4 show some inconsistencies. </li></ul><ul><ul><ul><li>Radiometric accuracy as expected </li></ul></ul></ul><ul><ul><ul><li>Average TB shows strange behavior </li></ul></ul></ul>Igarss '11 - Vancouver
  12. 12. Polarisation signature <ul><li>Dome C only, Hallikainen model (one layer, Tsnow=-54) </li></ul>Igarss '11 - Vancouver DomeX data, G. Macelloni Tv Domex-2 operative 2009 Th Domex-2 operative 2009 Th Domex-2 Initial 2009 Tv Domex-2 Initial 2009 Tv domex2010 th domex2010
  13. 13. Absolute brightness temperature accuracy <ul><li>SMOS estimates of TB over Dome C although somewhat noisier, compare well with on-ground measurements </li></ul>Igarss '11 - Vancouver
  14. 14. Bias variations within FoV <ul><li>Different behaviour observed within AF-FoV and EAF-FoV </li></ul><ul><li>Clear change around april </li></ul>Igarss '11 - Vancouver
  15. 15. Dielectric constants Igarss '11 - Vancouver Antarctica: Re and Im *10 + 220 (magenta) ECMWF temperature (blue)
  16. 16. Stability and radiometric accuracy over Dome Concordia <ul><li>Request for additional statistics and analysis : </li></ul><ul><ul><li>Within the field of view </li></ul></ul><ul><ul><li>With respect to differential long term drift </li></ul></ul><ul><ul><li>METRICS understood as linear temporal trend of average brightness temperature </li></ul></ul><ul><li>Analysis of reprocessed data set with new antenna model </li></ul><ul><ul><li>2010 from reprocessing </li></ul></ul><ul><ul><li>2010 from selected subset </li></ul></ul>Igarss '11 - Vancouver
  17. 17. Analysis of acquisitions over Dome C Igarss '11 - Vancouver
  18. 18. Long term stability <ul><li>Over 15 months, trends at 42° almost disappears. </li></ul><ul><li>But only impact of January. Over 2010, drift was -0.22K/yr, now -0.72K/yr with new data set. Std(TB) slightly increase </li></ul><ul><li>TBH shows signs of a seasonal effect, observed on ground </li></ul>Igarss '11 - Vancouver
  19. 19. Long term stability Igarss '11 - Vancouver
  20. 20. Long term stability in ground reference frame Igarss '11 - Vancouver
  21. 21. METRICS Igarss '11 - Vancouver TX TY T3 T4 TX TY T3 T4 TH TV T3 T4 TH TV T3 T4
  22. 22. Radiometric Accuracy over Dome C <ul><li>Over 15 months of data, Dome C has been seen almost 260000 times in full pol, spanning the entire EAF Fov. </li></ul><ul><li>Assuming the target has not changed, we can compute radiometric accuracy as the standard deviation of measured brightness temperature within the FoV. </li></ul>Igarss '11 - Vancouver Old Antenna Model Radiometric Acc. (K) Antenna (Surface) X pol (H pol) Y pol (V pol) X from XY (H from XY) Y from XY (V from XY) T3 T4 Theoretical at boresight 2.12 2.17 3.45 3.47 2.94 2.94 Measured at boresight 2.48(2.48) 2.39(2.38) 4.09(4.07) 3.81(3.84) 2.91(5.75) 3.11(6.22) Measured in 0.3 circle 2.71(2.79) 2.56(2.61) 4.15(4.17) 4.18(4.18) 3.26(6.11) 3.18(6.37) Measured in AF FoV 2.82(2.97) 2.70(2.79) 4.29(4.35) 4.34(4.34) 3.39(6.20) 3.29(6.57) Measured in EAF FoV 3.29(3.74) 3.33(3.62) 5.12(4.76) 5.28(4.78) 4.09(7.07) 4.01(8.01) New Antenna Model Radiometric Acc. (K) Antenna (Surface) X pol (H pol) Y pol (V pol) X from XY (H from XY) Y from XY (V from XY) T3 T4 Theoretical at boresight 2.08 2.15 3.36 3.47 2.90 2.90 Measured at boresight 2.35(2.36) 2.58(2.36) 4.10(4.08) 3.99(4.00) 2.91(5.73) 3.15(6.29) Measured in 0.3 circle 2.56(2.65) 2.61(2.68) 4.08(4.12) 4.21(4.19) 3.24(6.08) 3.18(6.35) Measured in AF FoV 2.67(2.82) 2.73(2.82) 4.21(4.30) 4.36(4.34) 3.37(6.17) 3.28(6.56) Measured in EAF FoV 3.19(3.66) 3.27(3.56) 4.97(4.66) 5.29(4.72) 4.03(6.99) 3.93(7.85)
  23. 23. Radiometric performances Igarss '11 - Vancouver
  24. 24. Radiometric performances 3/4 Igarss '11 - Vancouver
  25. 25. New antenna model summary <ul><li>Mixed results for biases correction. </li></ul><ul><ul><li>Clear improvement in ground reference frame from may onwards. </li></ul></ul><ul><ul><li>Antenna reference frame results unconclusive. </li></ul></ul><ul><ul><li>T3/T4 rather unclear, mostly degrades. </li></ul></ul><ul><li>Marginal gain on radiometric accuracy </li></ul>Igarss '11 - Vancouver
  26. 26. Conclusions <ul><li>Still homework to be done with </li></ul><ul><ul><li>Calibration </li></ul></ul><ul><ul><li>Stokes 3 and 4 </li></ul></ul><ul><li>Variations within field of view still not totally mastered </li></ul><ul><li>But overall performances in radiometry and geolocation out performs specifications </li></ul><ul><li>Long term drift starting to be understood ( and thus correction within reach </li></ul>Igarss '11 - Vancouver

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