Extinction‐ice water content‐effective radius algorithms for CALIPSO

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