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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.

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Presentation on theme: "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."— Presentation transcript:

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 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 Outline

3 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 3 Terra and Aqua MODIS

4 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 On-orbit Operation and Calibration Activities Page 4 No changes to instrument operational configurations in recent years

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 5

6 On-orbit Calibration Activities Page 6 SD / SDSM MOON BB WUCD SRCA RAD SRCA SPEC SRCA SPAT Terra Aqua 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

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

8 Instrument Temperatures Page K increase over 11 years2.0 K increase over 9 years T-MODISA-MODIS Similar trends for warm FPA, scan cavity, and mirror temperatures VIS, NIR T-MODISA-MODIS VIS, NIR

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

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

11 Solar Diffuser (SD) Degradation Page 11 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-MODISA-MODIS SD degradation (mission-long trend) Gradually reduced SD calibration frequency as mission continues

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

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

15 On-orbit Changes in Spectral Band CW and BW Page 15 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 On-orbit Changes in Band-to-Band Registration (BBR) Page 16 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 Page 17 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 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) Summary Page 18

19 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 Challenges Page 19

20 MODIS Specifications and Applications –20 reflective solar bands (RSB: bands 1-19, and 26) from  m –16 thermal emissive bands (TEB: bands 20-25, 27-36) from  m Page 20


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