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Proceedings Paper

Spectral characterization of MODIS Airborne Simulator (MAS) LWIR bands and application to MODIS science data cloud products
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Paper Abstract

Several MODIS cloud product algorithms are being developed at the University of Wisconsin for the generation of day-1 products after the launch of MODIS. MODIS Airborne Simulator (MAS) radiometric data collected form NASA's ER-2 platform is being used to simulate MODIS spectral bands for testing and refinement of the cloud product algorithms. Spectral characterization is an important component of the MAS calibration. MAS LWIR bands are spectrally characterized in ambient conditions using a monochromator and are corrected for source spectral shape and atmospheric attenuation. An atmospheric correction based on LBLRTM forward model transmittances demonstrates that strong spectral absorption features, such as Q-branch CO2 absorption near 13.9 micrometers , are effectively removed from the spectral measurements with the aid of a small spectral position correction. Comparisons of MAS in-flight data to well- calibrated HIS instrument data indicate that MAS LWIR spectral calibration drift over time is less than 5 percent of FWHM. The MODIS CO2 cloud top height retrieval shows small dependence on the spectral characterization, with retrieved cloud top height changing by less than 0.5 km in response to a 5 percent spectral position change. This is within the tolerance of other error sources in the cloud top properties algorithm.

Paper Details

Date Published: 18 September 1997
PDF: 9 pages
Proc. SPIE 3117, Earth Observing Systems II, (18 September 1997); doi: 10.1117/12.283810
Show Author Affiliations
Christopher C. Moeller, Univ. of Wisconsin/Madison (United States)
Daniel Darch LaPorte, Univ. of Wisconsin/Madison (United States)
Pavel Hajek, NASA Ames Research Ctr. (United States)
Kathleen I. Strabala, Univ. of Wisconsin/Madison (United States)
W. Paul Menzel, NOAA (United States)


Published in SPIE Proceedings Vol. 3117:
Earth Observing Systems II
William L. Barnes, Editor(s)

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