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Proceedings Paper

Retrieval of cloud top height, effective emissivity, and particle size, from aircraft high-spectral-resolution infrared measurements
Author(s): Paolo B. Antonelli; Steven A. Ackerman; W. Paul Menzel; Hung-Lung Huang; Bryan A. Baum; William L. Smith
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Paper Abstract

In this study we compare different approaches to retrieve Cloud Top Height (CTH), Cloud Effective Emissivity (CEE), and the Cloud Particle Size (CPS) from aircraft high-spectral resolution infrared measurements. Two independent methods are used to infer CTH. One approach is based on a high spectral resolution version of the CO2 Slicing algorithm characterized by a statistically based selection of the optimal channel pairs. Another approach the Minimum Local Emissivity Variance algorithm (MLEV) takes advantage of high-resolution observations in the 8-12 micron region to simultaneously derive CTH and CEE. Once CTH has been retrieved a third method, based on the comparison between simulated and observed radiances, is used to infer CPS and CEE. Simulated radiances are computed for 18 microwindows between 8.5 and 12 microns. The cirrus scattering calculations are based on three-dimensional randomly oriented ice columns assuming six different particle size distributions. Multiple scattering calculations are performed for 26 different cloud optical thicknesses (COT) between 0 and 20. The simulated radiances are then compared to the observed radiances to infer COT and CPS for each spectral measurement. We applied these approaches to High-resolution Interferometer Sounder (HIS), National Polar-Orbiting Operational Environmental Satellite System Airborne Sounder Testbed-Interferometer (NAST-I) and Scanning-HIS (S-HIS) data. The preliminary results, consistent between the different algorithms, suggest that the high spectral resolution measurements improve the accuracy of the cloud property retrievals.

Paper Details

Date Published: 31 January 2002
PDF: 12 pages
Proc. SPIE 4539, Remote Sensing of Clouds and the Atmosphere VI, (31 January 2002); doi: 10.1117/12.454468
Show Author Affiliations
Paolo B. Antonelli, Univ. of Wisconsin/Madison (United States)
Steven A. Ackerman, Univ. of Wisconsin/Madison (United States)
W. Paul Menzel, Univ. of Wisconsin/Madison (United States)
Hung-Lung Huang, Univ. of Wisconsin/Madison (United States)
Bryan A. Baum, NASA Langley Research Ctr. (United States)
William L. Smith, NASA Langley Research Ctr. (United States)

Published in SPIE Proceedings Vol. 4539:
Remote Sensing of Clouds and the Atmosphere VI
Klaus Schaefer; Olga Lado-Bordowsky; Adolfo Comeron; Michel R. Carleer; Janet S. Fender, Editor(s)

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