STRATIFORM AND CONVECTIVE CLASSIFICATION OF RAINFALL USING SSM I 85-GHZ BRIGHTNESS TEMPERATURE OBSERVATIONS/

A better understanding of global climate calls for more accurate estim ates of liquid and ice water content profiles of precipitating clouds and their associated latent heating profiles. Convective and stratifor m precipitation regimes have different latent heating and therefore im pact the earth's climate differently. Classification of clouds over oc eans has traditionally been part of more general rainfall retrieval sc hemes. These schemes are based on individual or combined visible and i nfrared, and microwave satellite observations. However, none of these schemes report validations of their cloud classification with independ ent ground observations. The objective of this study is to develop a s cheme to classify convective and stratiform precipitating clouds using satellite brightness temperature observations. The proposed scheme pr obabilistically relates a quantity called variability index (VI) to th e stratiform fractional precipitation coverage over the satellite fiel d of view (FOV). The VI for a satellite pixel is the mean absolute 85- GHz brightness temperature difference between the pixel and the eight surrounding neighbor pixels. The classification scheme has been applie d to four different rainfall regimes. All four regimes show that the f requency of stratiform rainfall in the satellite FOV increases as the satellite-based VI decreases. The results of this study demonstrate th at the satellite-based VI is consistently related to the probability o f occurrence of three classes (0%-40%, 40%-70%, and 70%-100%) of FOV s tratiform coverage.