Ice clouds size distributions (SDs), ice water content (IWC), and their dependence on temperature - what thousands of SDs tell us

Description

Ice clouds are an important factor affecting climate, and statistical properties of ice cloud microphysical parameters are of great importance for climate modeling. Cloud temperature is expected to be one of the main parameters governing cloud microstructure (Korolev et al. 2001). Ice cloud SDs'' behavior and IWC values versus temperature were evaluated to demonstrate this sensitivity, using in situ data from several U.S. DOE ARM field campaigns. Ice particle size spectra parameters and IWC were averaged into five-degree temperature bins. Next, the effective diameter (Deff) was estimated as a function of temperature with ice particle shape assumptions for different cirrus cloud types. Several scenarios will be presented, dependent on geographic location where the measurements were made. SD shape (the dispersion, the degree of bimodality) for all scenarios will be specified, from which ice cloud radiative properties can be determined. These results may help improve the mid-latitude and tropical ice cloud parameterization schemes for GCMs.