Characterization of the microphysics of ice in tropical convection for rain retrieval algorithms

Megha-Tropiques is a joint satellite between France and India to study the water and energy cycle in the Tropics. The satellite is part of GPM and will provide a exceptional sampling of the 23° S-23° N region because of the low inclination of the orbit (20°) combined with the large swath (1700 km) of its main instrument MADRAS. MADRAS is a 9-channel passive microwave radiometer dedicated mainly to precipitation retrieval. Bauer et al (2005) showed that the most critical source of uncertainties in the precipitation retrieval over land comes from the ice microphysics characteristics. In the framework of the Megha-Tropiques mission we tried to improve the parameterization of precipitating ice in the radiative transfer model. Datasets from three field experiments (Niamey 2010, Gan 2011 and CHUVA) will be used here. Niamey 2010 and Gan 2011 were specifically designed to study these ice particles. A combination of ground-based (X and S-band) and airborne (W-band) radars were used in conjunction with in-situ microphysics. CHUVA, is more generally dedicated to study the rain regimes over various regions of Brazil, sees the deployment of a ground-based polarimetric X-band radar. We will show some comparisons of Particles IDentification (PID) made from the various polarimetric radars in continental Africa, Indian Ocean and continental Brazil respectively. Building some statistics, we will try to show how the life cycle of the system and the various environments impact on the ice microphysics characteristics and consequently will be taken into account in the rain retrieval algorithm for MADRAS on Megha-Tropiques