Application of Zphi® algorithm on AMMA radar data: description of west african squall lines

During the 2006 Special Observation Period of the African Monsoon Multidisciplinary Analysis (AMMA) different instruments and especially radars and raingauges were deployed over West Africa. Among those radars the C-band RONSARD in Kopargo (Benin) and X-band XPORT in Djougou (Benin) were almost co-localized (18 km apart). The data from these two weather polarimetric Doppler radars can be processed by Zphi® to correct for attenuation effects and retrieve microphysics information. Zphi® is a French software making use of the polarization variables measured by radar that allows us to perform quantitative rain estimates (QRE). The aim of using these radars was to analyze the microphysics structure of west African squall lines. The microphysics observed differences can be explained by the dynamics which is available with the Doppler feature of the radars. More specifically our study of squall lines microphysics and dynamics, is based on a systematic processing of the whole radar dataset including correction of ground clutters, noise, calibration and inter-calibration between the two radars and also with respect to the raingauges. The Zphi® algorithm taking care of attenuation correction. We also developped a specific method to dealias wind Doppler fields on both radars. This presentation will focus on the comparison between both C-band and X-band radars in terms of could microphysics and dynamics, and then with raingauges in terms of QRE.