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.
AJ Heymsfield, D Winker, GJ van Zadelhoff. Extinction-ice water content-effective radius algorithms for CALIPSO
published, Geophys. Res. Lett., 2005, 32