Retrieval of microphysical variables by a diagnostic modelling study: comparison between parameterized and detailed warm microphysics

Abstract

Retrieval of microphysical fields associated with a wind field deduced from Doppler radar data is performed with a model based on the use of continuity equations for heat and water substance. Both detailed and parameterized microphysical schemes have successively been incorporated in the model and fields retrieved from both schemes are compared in the case of the convective part of a tropical squall line. The retrieved fields display fairly similar features when considered for the whole convective region. However, the efficiency of microphysical processes responsible for the production of rain at local scale depends on the microphysical scheme incorporated in the model. The rate of evaporation of rain in unsaturated air is also sensitive to the microphysical scheme. Both models are able to reproduce intense precipitation observed by the radars and a rain gauge with a slightly better agreement in the case of the detailed model. Drop size distributions simulated by the detailed model are analyzed in relation to their normalization, effective precipitation processes and wind field. In zones of intense precipitation, they display features similar to those of a gamma distribution. In convective zones with intense updraughts, they display quite different features. Implications for the interpretation of integrated parameters of size distributions of rain are examined.