Retrieval of IWC inside mixed-phase clouds using dual polarization spectral radar measurements

Abstract

In most part of the troposphere the temperature is negative. It induces some regions where thropspheric clouds are composed by a mix of ice crystals and supercooled water droplets. Nevertheless those clouds are still poorly represented in climate models (Hogan et al., 2003) even if their influences on cloud evolution, cloud scale dynamics and the surface energy budget are relevant ( Cess & al., 1995, Harrington & Olsson, 2001, Shape & Interieri, 2004).
A new technique is under development in the University of Delft for remotely determining IWC inside mixed-phase clouds from measurements taken by the S band Doppler Polarimetric radar TARA and combining it with a microphysical model (appendix D: Spek et al., 2005). This constitutes a first step in the retrieval of IWC and LWC from a radar/ lidar synergy. Since radars and lidars are sensitive to different types of particles the relative differences between both devices backscattered signals contain information on the particles being probed i.e. the WC.