
Proceedings Paper
Improvement of MODIS RSB calibration by minimizing the Earthshine impact on solar diffuser observationsFormat | Member Price | Non-Member Price |
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Paper Abstract
The MODerate Resolution Imaging Spectroraiometer (MODIS) reflective solar bands (RSB) are calibrated on-orbit
using solar illuminations reflected from its onboard solar diffuser (SD) plate. The specified calibration uncertainty
requirements for MODIS RSB are ±2% in reflectance and ±5% in radiance at their typical top of atmosphere (TOA)
radiances. The onboard SD bi-directional reflectance factor (BRF) was characterized pre-launch by the instrument
vendor using reference samples traceable to NIST reflectance standard. The SD on-orbit degradation is monitored
using a solar diffuser stability monitor (SDSM). One of contributors to the RSB calibration uncertainty is the
earthshine (ES) illumination on the SD plate during SD calibration. This effect was estimated pre-launch by the
instrument vendor to be of 0.5% for all RSB bands. Analyses of on-orbit observations show that some of the SD
calibration data sets have indeed been contaminated due to extra ES illumination and the degree of ES impact on the
SD calibration is spectrally dependent and varies with geo-location and atmospheric conditions (ground surface type
and cloudiness). This paper illustrates the observed ES impacts on the MODIS RSB calibration quality and compare
them with the effects derived from an ES model based on the viewing geometry of MODIS SD aperture door and
likelihood atmospheric conditions. It also describes an approach developed to minimize the ES impact on MODIS
RSB calibration.
Paper Details
Date Published: 7 September 2006
PDF: 10 pages
Proc. SPIE 6296, Earth Observing Systems XI, 629608 (7 September 2006); doi: 10.1117/12.679081
Published in SPIE Proceedings Vol. 6296:
Earth Observing Systems XI
James J. Butler, Editor(s)
PDF: 10 pages
Proc. SPIE 6296, Earth Observing Systems XI, 629608 (7 September 2006); doi: 10.1117/12.679081
Show Author Affiliations
X. Xie, Science Systems and Applications, Inc. (United States)
X. Xiong, NASA Goddard Space Flight Ctr. (United States)
X. Xiong, NASA Goddard Space Flight Ctr. (United States)
R. Wolfe, NASA Goddard Space Flight Ctr. (United States)
A. Lyapustin, Univ. of Maryland, Baltimore County (United States)
A. Lyapustin, Univ. of Maryland, Baltimore County (United States)
Published in SPIE Proceedings Vol. 6296:
Earth Observing Systems XI
James J. Butler, Editor(s)
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