OBSERVATIONAL STUDY OF RAIN MICROPHYSICS AND RAIN RETRIEVAL USING POLARIMETRIC RADAR DATA

Abstract

Accurate quantitative precipitation estimation (QPE) and quantitative precipitation forecasts (QPF) require accurate microphysical parameterization/modeling of the precipitation. This study presents the modeling of rain microphysics and the application of polarimetric weather radar on rain retrievals. There are three topics addressed in this study. The first topic is the study of raindrop size distribution (DSD) through in-situ disdrometer observations. The observational error of disdrometer is quantified and corresponding error effects in developing DSD model are analyzed. The second topic is the characterization of rain microphysics with the linkage to radar observations. Empirical relations of rain-radar variables are developed for X-, C- and S-band polarimetric radars. The third topic is the retrieval of DSD parameters from polarimetric radar data (PRD). Three different approaches: direct retrieval, Bayesian retrieval and variational retrieval, are introduced. The latter two methods are promising with the optimal use of radar data. Their performance and potential are analyzed and discussed.