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Proceedings Paper

Fast generic millimeter-wave emissivity model
Author(s): Stephen J. English; Tim J. Hewison
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Paper Abstract

In recent year san increasingly diverse range of passive microwave satellite data has become available for applications in numerical weather forecasting, climate studies and environmental monitoring. Top of atmosphere radiance is measured, which as originated from both the surface and the atmosphere. When retrieving atmospheric quantities such as temperature, humidity or cloud liquid water content near the surface it is necessary to account correctly for the contribution to the measured radiance from the surface. This depends on the surface emissivity, which varies widely with surface type, roughness and temperature. For real time applications such as numerical weather forecasting, it is necessary to be able to model the surface emissivity very quickly. There is therefore a need for a fast surface emissivity model has therefore been developed. This is a semi-empirical mode. Some aspects are physically based, for example many surface scan be assumed to be di- electric media. Other aspects such as geometric roughness have been parameterized for speed. For some complex or poorly understood aspects of the electromagnetic interaction empirical adjustments are made to fit observed values. The model has been compared with emissivities derived from aircraft radiometer measurements at 24, 50, 89 and 157 GHz. It is also intended to compare with data from the special sensor microwave imager and advanced microwave sounding unit instruments. For the ocean surface the fast model fits estimated emissivities from airborne radiometers two within 1-2 percent, and it fits the unparameterized model to within 0.1-3 percent.

Paper Details

Date Published: 19 August 1998
PDF: 13 pages
Proc. SPIE 3503, Microwave Remote Sensing of the Atmosphere and Environment, (19 August 1998); doi: 10.1117/12.319490
Show Author Affiliations
Stephen J. English, U.K. Meteorological Office (United Kingdom)
Tim J. Hewison, U.K. Meteorological Office (United Kingdom)

Published in SPIE Proceedings Vol. 3503:
Microwave Remote Sensing of the Atmosphere and Environment
Tadahiro Hayasaka; Dong Liang Wu; Yaqiu Jin; JingShang Jiang, Editor(s)

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