Download - PR5 IGARSS_2011_MODIS.ppt
Summary of Terra and Aqua MODIS Summary of Terra and Aqua MODIS Long-term PerformanceLong-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
EOS
• 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
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Outline
Aqua
Terra Terra: over 11 years of successful operationAqua: 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
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Terra and Aqua MODIS
• 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
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No changes to instrument operational configurations in recent years
On-orbit Calibration Activities
SDSM
Scan Mirror
SolarDiffuser
SRCA
Blackbody
SpaceView
SD/SDSM:Weekly to tri-
weekly
SRCA:Radiometric:
monthlySpatial: bi-
monthlySpectral: quarterly
Moon: monthly (nighttime orbits)0-20o spacecraft roll maneuvers55o phase angle
BB: quarterly WUCDSpacecraft maneuvers:
Yaw (SD BRF, VF)Roll (Moon)Pitch (only applied to
Terra) Page 5
On-orbit Calibration Activities
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SD / SDSM
MOONBB
WUCDSRCA RAD
SRCA SPEC
SRCA SPAT
Terra 325 103 76 135 48 63
Aqua 216 83 39 107 27 45
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
• Temperatures (Instrument and FPA)
• On-board Calibrators (BB and SD)
• Radiometric
• Spectral
• Spatial
• Geometric
Performance
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Instrument Temperatures
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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
Cold FPA Temperatures
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T-MODIS A-MODISSMIR, LWIR SMIR, LWIR
Short-term: granule averaged
Extremely stable
Short-term: granule averaged
Less stable (recent loss of cooler margin)
Blackbody Temperatures (nominal operation)
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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)
Solar Diffuser (SD) Degradation
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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
On-orbit Changes in RSB (VIS, NIR, and SWIR) Responses
Page 12Wavelength, angle of incidence (AOI), and mirror side dependent
On-orbit Changes in TEB (MWIR and LWIR) Responses
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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)
Detector Characterization
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• 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
On-orbit Changes in Spectral Band CW and BW
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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
On-orbit Changes in Band-to-Band Registration (BBR)
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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
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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
• 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
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• 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
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EOS
MODIS Specifications and Applications
– 20 reflective solar bands (RSB: bands 1-19, and 26) from 0.41 - 2.2m– 16 thermal emissive bands (TEB: bands 20-25, 27-36) from 3.5 - 14.4m Page 20