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Radiance and Jacobian Intercomparison of Radiative Transfer Models Applied to HIRS and AMSU ChannelsThe goals of this study are the evaluation of current fast radiative transfer models (RTMs) and line-by-line (LBL) models. The intercomparison focuses on the modeling of 11 representative sounding channels routinely used at numerical weather prediction centers: 7 HIRS (High-resolution Infrared Sounder) and 4 AMSU (Advanced Microwave Sounding Unit) channels. Interest in this topic was evidenced by the participation of 24 scientists from 16 institutions. An ensemble of 42 diverse atmospheres was used and results compiled for 19 infrared models and 10 microwave models, including several LBL RTMs. For the first time, not only radiances, but also Jacobians (of temperature, water vapor and ozone) were compared to various LBL models for many channels. In the infrared, LBL models typically agree to within 0.05-0.15 K (standard deviation) in terms of top-of-the-atmosphere brightness temperature (BT). Individual differences up to 0.5 K still exist, systematic in some channels, and linked to the type of atmosphere in others. The best fast models emulate LBL BTs to within 0.25 K, but no model achieves this desirable level of success for all channels. The ozone modeling is particularly challenging, In the microwave, fast models generally do quite well against the LBL model to which they were tuned. However significant differences were noted among LBL models, Extending the intercomparison to the Jacobians proved very useful in detecting subtle and more obvious modeling errors. In addition, total and single gas optical depths were calculated, which provided additional insight on the nature of differences. Recommendations for future intercomparisons are suggested.
Document ID
20010021316
Acquisition Source
Marshall Space Flight Center
Document Type
Preprint (Draft being sent to journal)
Authors
Garand, L.
(Meteorological Service of Canada Dorval, Quebec Canada)
Turner, D. S.
(Meteorological Service of Canada Downsview, Ontario Canada)
Larocque, M.
(Montreal Systems Consultants, Inc. Dorval, Quebec Canada)
Bates, J.
(National Oceanic and Atmospheric Administration Boulder, CO United States)
Boukabara, S.
(Atmospheric and Environmental Research, Inc. Cambridge, MA United States)
Brunel, P.
(Centre de Meteorologie Spatiale Lannion, France)
Chevallier, F.
(European Centre for Medium-Range Weather Forecasts Reading, United Kingdom)
Deblonde, G.
(Montreal Systems Consultants, Inc. Dorval, Quebec Canada)
Engelen, R.
(Colorado State Univ. Fort Collins, CO United States)
Hollingshead, M.
(Raytheon Co. Aurora, CO United States)
Goodman, H. Michael
Date Acquired
August 20, 2013
Publication Date
January 1, 2000
Subject Category
Geophysics
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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