A SCREENING METHODOLOGY FOR PASSIVE MICROWAVE PRECIPITATION RETRIEVALALGORITHMS

The success of any passive microwave precipitation retrieval algorithm relies on the proper identification of rain areas and the elimination of surface areas that produce a signature similar to that of precipit ation. A discussion on the impact of and on methods that identify area s of rain, snow cover, deserts, and semiarid conditions over land, and rain, sea ice, strong surface winds, and clear, calm conditions over ocean, are presented. Additional artifacts caused by coastlines and Sp ecial Sensor Microwave/Imager data errors are also discussed, and meth ods to alleviate their impact are presented. The strengths and weaknes ses of the ''screening'' techniques are examined through application o n various case studies used in the WetNet PIP-2. Finally, a methodolog y to develop a set of screens for use as a common rainfall indicator f or the intercomparison of the wide variety of algorithms submitted to PIP-2 is described.