Published on

  • Be the first to comment

  • Be the first to like this

No Downloads
Total views
On SlideShare
From Embeds
Number of Embeds
Embeds 0
No embeds

No notes for slide


  1. 1. Summary of Terra and Aqua MODIS Long-term Performance Jack Xiong 1 , Brian Wenny 2 , Sri Madhaven 2 , Amit Angal 3 , William Barnes 4 , and Vincent Salomonson 5 1. NASA /GSFC; 2. Sigma Space Corp; 3. SSAI; 4. UMBC; 5. U. of Utah Other Contributors: Members of MCST IGARSS 2011, July 24-29, 2011, Vancouver, Canada
  2. 2. <ul><li>MODIS </li></ul><ul><ul><li>Terra and Aqua </li></ul></ul><ul><li>On-orbit Operation and Calibration Activities </li></ul><ul><li>On-orbit Performance </li></ul><ul><ul><li>Instrument, Focal Plane Assembly (FPA) </li></ul></ul><ul><ul><li>On-board Calibrators (OBC) </li></ul></ul><ul><ul><li>Radiometric, Spectral, Spatial, and Geometric </li></ul></ul><ul><li>Summary </li></ul>Outline Page
  3. 3. Terra and Aqua MODIS Aqua Terra Terra: over 11 years of successful operation Aqua: over 9 years of successful operation MODIS observations: 36 spectral bands: 0.41 to 14.5  m ( VIS to LWIR ) 3 spatial resolutions: 0.25, 0.5, and 1 km Nearly 40 data products for land, ocean, and atmospheric applications Page
  4. 4. On-orbit Operation and Calibration Activities <ul><li>Terra MODIS </li></ul><ul><ul><li>A-side: launch to Oct 30, 2000 </li></ul></ul><ul><ul><li>B-side: Oct 30, 2000 to June 15, 2001 </li></ul></ul><ul><ul><li>A-side: July 02, 2001 to Sept 17, 2002 </li></ul></ul><ul><ul><li>A-side electronics & B-side formatter: Sept 17, 2002 to present </li></ul></ul><ul><ul><li>BB temperatures set at 290K </li></ul></ul><ul><ul><li>Cold FPA controlled at 83K </li></ul></ul><ul><li>Aqua MODIS </li></ul><ul><ul><li>B-side: launch to present </li></ul></ul><ul><ul><li>BB temperatures set at 285K </li></ul></ul><ul><ul><li>Cold FPA controlled at 83K </li></ul></ul>Page No changes to instrument operational configurations in recent years
  5. 5. On-orbit Calibration Activities SDSM Scan Mirror Solar Diffuser SRCA Blackbody Space View SD/SDSM: Weekly to tri-weekly SRCA: Radiometric: monthly Spatial: bi-monthly Spectral: quarterly Moon: monthly (nighttime orbits) 0-20 o spacecraft roll maneuvers 55 o phase angle BB: quarterly WUCD Spacecraft maneuvers: Yaw (SD BRF, VF) Roll (Moon) Pitch (only applied to Terra) Page
  6. 6. On-orbit Calibration Activities Page Frequencies to operate on-board calibrators are gradually reduced for both Terra and Aqua MODIS as a result of their extended missions Spacecraft Maneuvers: Yaw (SD BRF, VF), Roll (Moon), Pitch (only applied to Terra) Ground Calibration Targets: Dome C and Desert Sites As of June 30, 2011 SD / SDSM MOON BB WUCD SRCA RAD SRCA SPEC SRCA SPAT Terra 325 103 76 135 48 63 Aqua 216 83 39 107 27 45
  7. 7. Performance <ul><li>Temperatures (Instrument and FPA) </li></ul><ul><li>On-board Calibrators (BB and SD) </li></ul><ul><li>Radiometric </li></ul><ul><li>Spectral </li></ul><ul><li>Spatial </li></ul><ul><li>Geometric </li></ul>Page
  8. 8. Instrument Temperatures Page 3.5 K increase over 11 years 2.0 K increase over 9 years T-MODIS A-MODIS Similar trends for warm FPA, scan cavity, and mirror temperatures VIS, NIR T-MODIS A-MODIS VIS, NIR
  9. 9. Cold FPA Temperatures Page T-MODIS A-MODIS SMIR , LWIR SMIR , LWIR Short-term: granule averaged Extremely stable Short-term: granule averaged Less stable (recent loss of cooler margin)
  10. 10. Blackbody Temperatures (nominal operation) Page B-Side Short-term: granule averaged Short-term: granule averaged < 30 mK increase over 11 yr T-MODIS A-MODIS Extremely stable Aqua MODIS BB performance is extremely stable (long- and short-term)
  11. 11. Solar Diffuser (SD) Degradation Page Larger degradation at shorter  ; More SD degradation in Terra MODIS Increased SD degradation due to SD door fixed at “open” position SD degradation as a function of wavelength T-MODIS A-MODIS SD degradation (mission-long trend) Gradually reduced SD calibration frequency as mission continues
  12. 12. On-orbit Changes in RSB (VIS, NIR, and SWIR) Responses Page Wavelength, angle of incidence (AOI), and mirror side dependent
  13. 13. On-orbit Changes in TEB (MWIR and LWIR) Responses Page Excluding changes due to use of different operational configurations, changes in TEB responses are relatively small (compared to RSB); PV bands (20-25 and 27-30) are more stable than PC bands (31-36)
  14. 14. Detector Characterization Page <ul><li>36 spectral bands: 490 individual detectors </li></ul><ul><ul><li>Terra MODIS </li></ul></ul><ul><ul><ul><li>45 noisy detectors (30 from pre-launch; 35 at launch) </li></ul></ul></ul><ul><ul><ul><li>No inoperable detectors </li></ul></ul></ul><ul><ul><li>Aqua MODIS </li></ul></ul><ul><ul><ul><li>6 noisy detectors (2 from pre-launch; 3 at launch) </li></ul></ul></ul><ul><ul><ul><li>15 inoperable detectors (13 in band 6 and most since pre-launch and/or at launch) </li></ul></ul></ul><ul><ul><li>There are no new noisy and inoperable detectors in recent years </li></ul></ul>
  15. 15. On-orbit Changes in Spectral Band CW and BW Page Aqua MODIS on-orbit changes in both CW and BW are less than 0.5 nm for most VIS/NIR spectral bands Terra MODIS VIS and NIR spectral bands Changes in center wavelength (CW) are less than 0.5 nm for most VIS/NIR Changes in bandwidth (BW) are less than 1.0 nm for most VIS/NIR
  16. 16. On-orbit Changes in Band-to-Band Registration (BBR) Page Large BBR offsets in A-MODIS between cold FPA and warm FPA band pairs (a known problem since pre-launch); offsets remain stable Terra MODIS along-scan BBR Terra MODIS along-track BBR
  17. 17. Page Robert Wolfe et al. T-MODIS track RMS: 43/42m (C5/C6); scan RMS: 44/42m (C5/C6) A-MODIS track RMS: 47/45m (C5/C6); scan RMS: 53/51m (C5/C6); and small N/S hemispherical differences Terra MODIS Geolocation Results
  18. 18. Summary <ul><li>Both instruments continue to operate normally </li></ul><ul><ul><li>Stable instrument and warm FPA temperatures </li></ul></ul><ul><ul><li>CFPA temperatures stably controlled at 83K for Terra MODIS; small and slow increase (up to 0.30K) for Aqua MODIS CFPA temperatures </li></ul></ul><ul><li>All on-board calibrators continue to provide key design functions </li></ul><ul><ul><li>BB temperatures remain extremely stable for both Terra and Aqua MODIS, short- and long-term </li></ul></ul><ul><ul><li>Terra MODIS SD degradation is much larger than Aqua MODIS </li></ul></ul><ul><li>Radiometric </li></ul><ul><ul><li>Changes in responses are tracked and corrected in L1B calibration; other effect could exist due to large changes in VIS responses </li></ul></ul><ul><li>Spectral and Spatial </li></ul><ul><ul><li>Stable performance for both Terra and Aqua </li></ul></ul><ul><ul><li>No change to large BBR offsets in Aqua MODIS for band pairs between CFPA and WFPA (a known problem since pre-launch) </li></ul></ul>Page
  19. 19. Challenges <ul><li>Large changes in VIS spectral band/detector response </li></ul><ul><li>Large SD degradation at short wavelengths, especially in Terra MODIS </li></ul><ul><li>Aqua MODIS CFPA temperature stability (decrease of cooler margin) </li></ul><ul><li>Calibration consistency between Terra and Aqua MODIS (s cene dependent differences: offsets and trends) </li></ul><ul><li>MODIS lessons and experience for future missions </li></ul>Page
  20. 20. MODIS Specifications and Applications <ul><li>20 reflective solar bands (RSB: bands 1-19, and 26) from 0.41 - 2.2  m </li></ul><ul><li>16 thermal emissive bands (TEB: bands 20-25, 27-36) from 3.5 - 14.4  m </li></ul>Page