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Summary of Terra and Aqua MODIS Long-term Performance

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.

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Summary of Terra and Aqua MODIS Long-term Performance

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  1. Summary of Terra and Aqua MODIS Long-term Performance Jack Xiong1, Brian Wenny2, Sri Madhaven2, Amit Angal3, William Barnes4, and Vincent Salomonson5 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. Outline • MODIS • Terra and Aqua • On-orbit Operation and Calibration Activities • On-orbit Performance • Instrument, Focal Plane Assembly (FPA) • On-board Calibrators (OBC) • Radiometric, Spectral, Spatial, and Geometric • Summary Page 2

  3. Terra and Aqua MODIS Terra: over 11 years of successful operation Aqua: over 9 years of successful operation Terra MODIS observations: 36 spectral bands: 0.41 to 14.5 mm (VIS to LWIR) 3 spatial resolutions: 0.25, 0.5, and 1 km Nearly 40 data products for land, ocean, and atmospheric applications Aqua Page 3

  4. On-orbit Operation and Calibration Activities • Terra MODIS • A-side: launch to Oct 30, 2000 • B-side: Oct 30, 2000 to June 15, 2001 • A-side: July 02, 2001 to Sept 17, 2002 • A-side electronics & B-side formatter: Sept 17, 2002 to present • BB temperatures set at 290K • Cold FPA controlled at 83K • Aqua MODIS • B-side: launch to present • BB temperatures set at 285K • Cold FPA controlled at 83K No changes to instrument operational configurations in recent years Page 4

  5. On-orbit Calibration Activities SRCA: Radiometric: monthly Spatial: bi-monthly Spectral: quarterly SD/SDSM: Weekly to tri-weekly Solar Diffuser SRCA SDSM Blackbody Scan Mirror Space View BB: quarterly WUCD Spacecraft maneuvers: Yaw (SD BRF, VF) Roll (Moon) Pitch (only applied to Terra) Moon: monthly (nighttime orbits) 0-20o spacecraft roll maneuvers 55o phase angle Page 5

  6. On-orbit Calibration Activities As of June 30, 2011 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 Page 6

  7. Performance • Temperatures (Instrument and FPA) • On-board Calibrators (BB and SD) • Radiometric • Spectral • Spatial • Geometric Page 7

  8. Instrument Temperatures T-MODIS A-MODIS 3.5 K increase over 11 years 2.0 K increase over 9 years Similar trends for warm FPA, scan cavity, and mirror temperatures T-MODIS A-MODIS VIS, NIR VIS, NIR Page 8

  9. Cold FPA Temperatures T-MODIS SMIR, LWIR A-MODIS SMIR, LWIR Short-term: granule averaged Short-term: granule averaged Extremely stable Less stable (recent loss of cooler margin) Page 9

  10. Blackbody Temperatures (nominal operation) < 30 mK increase over 11 yr Extremely stable T-MODIS A-MODIS B-Side Short-term: granule averaged Short-term: granule averaged Aqua MODIS BB performance is extremely stable (long- and short-term) Page 10

  11. Solar Diffuser (SD) Degradation SD degradation as a function of wavelength T-MODIS A-MODIS Larger degradation at shorter l; More SD degradation in Terra MODIS SD degradation (mission-long trend) Increased SD degradation due to SD door fixed at “open” position Gradually reduced SD calibration frequency as mission continues Page 11

  12. On-orbit Changes in RSB (VIS, NIR, and SWIR) Responses Wavelength, angle of incidence (AOI), and mirror side dependent Page 12

  13. On-orbit Changes in TEB (MWIR and LWIR) Responses 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) Page 13

  14. Detector Characterization • 36 spectral bands: 490 individual detectors • Terra MODIS • 45 noisy detectors (30 from pre-launch; 35 at launch) • No inoperable detectors • Aqua MODIS • 6 noisy detectors (2 from pre-launch; 3 at launch) • 15 inoperable detectors (13 in band 6 and most since pre-launch and/or at launch) • There are no new noisy and inoperable detectors in recent years Page 14

  15. On-orbit Changes in Spectral Band CW and BW 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 Aqua MODIS on-orbit changes in both CW and BW are less than 0.5 nm for most VIS/NIR spectral bands Page 15

  16. On-orbit Changes in Band-to-Band Registration (BBR) Terra MODIS along-scan BBR Terra MODIS along-track BBR Large BBR offsets in A-MODIS between cold FPA and warm FPA band pairs (a known problem since pre-launch); offsets remain stable Page 16

  17. Terra MODIS Geolocation Results 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 Page 17

  18. Summary • Both instruments continue to operate normally • Stable instrument and warm FPA temperatures • CFPA temperatures stably controlled at 83K for Terra MODIS; small and slow increase (up to 0.30K) for Aqua MODIS CFPA temperatures • All on-board calibrators continue to provide key design functions • BB temperatures remain extremely stable for both Terra and Aqua MODIS, short- and long-term • Terra MODIS SD degradation is much larger than Aqua MODIS • Radiometric • Changes in responses are tracked and corrected in L1B calibration; other effect could exist due to large changes in VIS responses • Spectral and Spatial • Stable performance for both Terra and Aqua • No change to large BBR offsets in Aqua MODIS for band pairs between CFPA and WFPA (a known problem since pre-launch) Page 18

  19. Challenges • Large changes in VIS spectral band/detector response • Large SD degradation at short wavelengths, especially in Terra MODIS • Aqua MODIS CFPA temperature stability (decrease of cooler margin) • Calibration consistency between Terra and Aqua MODIS (scene dependent differences: offsets and trends) • MODIS lessons and experience for future missions Page 19

  20. MODIS Specifications and Applications • 20 reflective solar bands (RSB: bands 1-19, and 26) from 0.41 - 2.2mm • 16 thermal emissive bands (TEB: bands 20-25, 27-36) from 3.5 - 14.4mm Page 20

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