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On-orbit Cross-calibration of AM Satellite Remote Sensing Instruments Using the Moon. International Workshop on Radiometric & Geometric Calibration Grand Casino Gulfport Hotel Gulfport, MS 39501 December 4, 2003 Jim Butler NASA’s GSFC Code 924 Laser Remote Sensing Branch
International Workshop on Radiometric & Geometric Calibration
Grand Casino Gulfport Hotel
Gulfport, MS 39501
December 4, 2003
Laser Remote Sensing Branch
Greenbelt, MD 20771
+Appropriate radiance range for Earth-viewing instruments
+Photometric properties are virtually invariant (<10-8/yr)
+Spectrally bland (from returned Apollo samples)
+Accessible to spacecraft regardless of orbit
+Useful as a common transfer source between spacecraft
-Non-uniform reflectance and complex photometric behavior
-Satellite instrument lunar views may require a spacecraft attitude maneuver
•MISR, ASTER, ALI, Hyperion, SeaWiFS, & MODIS (Earth view port) on 4/14/03
•MODIS (Space view port) 8 to 12 times a year w/ no maneuver
The Moon as an On-orbit Calibration TargetThe Moon has advantages (+) and disadvantages (-) when used as a satellite instrument calibration target.
The Moon is equivalent to a 6 km target from a 705 km orbit
AM Constellation Spacecraft & Instruments
1. ALI MS/Pan 1 21:39:47
2. ALI MS/Pan 2 21:44:34
3. ALI MS/Pan 3 21:49:19
4. Hyperion 21:54:31
5. MISR Df camera 22:01:38
6. MISR Cf camera 22:02:33
7. MISR Bf camera 22:04:05
8. MISR Af camera 22:06:23
9. MODIS 22:09:24
10. MISR An camera 22:09:34
11. ASTER SWIR 22:09:34
12. ASTER VNIR-nadir 22:09:34
13. MISR Aa camera 22:12:46
14. ASTER VNIR-aft 22:13:22
15. MISR Ba camera 22:15:04
16. MISR Ca camera 22:16:37
17. MISR Da camera 22:17:33
18. SeaWiFS 22:34:14
MODIS 645.5nm Band
MISR 672nm Band
NOTE: The ROLO lunar image database is unique and extensive. The substantial spatial, phase angle, and wavelength coverage are far beyond any published prior work.
-Absolute accuracy of ROLO measurements is TBD
-Relative differences between instruments due to
1. Use of different solar irradiance spectra
2. Different approaches in calculating integrated lunar radiances from
instrument lunar images
3. Inherent differences/uncertainties in instrument calibrations
-Comparison of MODIS instruments at three different lunar
1. MODIS Terra: 1 through Earth view port +
25 through Space view port (2 angles of inc. on scan mirror).
2. MODIS Aqua: 10 through space view port.
-Average of all lunar views for each instrument: SeaWiFS (70);
ALI (29); MODIS Terra (26); Hyperion (9); MISR (1)
-Correcting for correlated time jitter (left), a clear asymptotic degradation trend is seen in Bands 7 and 8 (right).
-Degradation information determined through repeated lunar views is used in the generation of SeaWiFS standard data products.
MODIS Terra & Aqua Band-to-
MISR An Camera Band-to-band Differences
-Results from 5 VC expts. + 1 lunar
-Normalized VC and lunar results
show identical band-to-band trends
-Lunar and U of A results show similar
-Absolute scale not established in lunar
“All you have to do is look at the Moon.” Hugh Kieffer
“Once you look at the Moon, you may see amazing things.” Hugh Kieffer