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Journal of Geophysical Research: Atmospheres

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This study examines the potential of spatial modeling using geographic information systems (GIS) to improve the precipitation estimates based on Special Sensor Microwave/Imager (SSM/I) over the Tibetan Plateau. The monthly SSM/I precipitation estimates are based on the algorithm developed at the National Environmental Satellite, Data and Information Service (NESDIS) of the National Oceanic and Atmospheric Administration (NOAA). When using SSM/I estimates to predict station precipitation directly, the R2 values ranged from 0.005 to 0.624, with a mean of 0.334 for all months. When terrain and location variables obtained from the GIS were added to the models, the R2 values improved to range from 0.217 to 0.739 with a mean of 0.590 for all months. These variables represent effects of orographic forcing of topography, rain barrier/rain shadow, direction of moisture-bearing winds, and distance to the sources of moisture over the Tibetan Plateau. Results from this study suggest that region-specific algorithms are necessary for the SSM/I precipitation estimates over the Tibetan Plateau and that topographic analysis based on GIS can contribute significantly in improving the performance of SSM/I estimates.


Copyright 2004 by the American Geophysical Union