Rain drop size distribution variability and impact on X-band polarimetric radar retrieval: Results from the AMMA campaign in Benin

During the African Monsoon Multidisciplinary Analysis (AM MA) field campaign. polarimetric weather radars, a ram-gauge network and disdrometers were available to analyse the convective systems and the rainfall in Benin In this impel a three-year dataset of drop size distributions is used to compute theoretical relationships between X-band polarimetric variables and the rain rate, adjusted lot the region of interest The variability of these relationships from storm to storm and between ram types is studied With an X-band polarimetric radar the ram rate can be retrieved from the differential specific phase shift K-DP the specific attenuation A(H), the reflectivity Z or differential reflectivity Z(DR) corrected for attenuation. or a combination of these variables. The set of coefficients needed to run the rain retrieval or the attenuation collection schemes under the conditions found in Benin are computed. The rain retrieval schemes are compared on the basis of simulations The retrievals based on one single propagative variable like K-DP or A(H) perform well Prelimmary results from direct comparisons between X-band polarimetric radar estimates and lain-gauges are consistent with the disdrometer-based analysis Copyright (C) 2010 Royal Meteorological Society