Extinction-ice water content-effective radius algorithms for CALIPSO

Interrelationships between volume extinction oefficient, ice water content (IWC), and effective radius (Reff), each dependent upon the particle size distribution (PSD) and temperature (T), are developed using in-situ microphysical measurements at low and midlatitudes, remote sensing data, and model results. The ratio IWC/extinxtion, proportional to Reff, increases with T. Lower values of [IWC/extinction] are observed near cloud top and base than within a cloud layer, although [IWC/extinction] changes more with temperature than relative height within the cloud. For equivalent radar reflectivities (Ze) below about 28 dB, the minimum detectable with forthcoming spaceborne cloud radar, [IWC/extinxtion] is a nearly constant value. IWC increases almost linearly with extinction, with a temperature-dependence noted.