The impact of ice cloud particle microphysics on the uncertainty of ice water content retrievals

Ice water content (IWC) is a standard product of cloud radar measurements. In this work, cloud radar cross-sections of various ice clouds are modeled to examine the relationship between the radar signal and the IWC. We report that using backscatter signal at cloud radar wavelength to retrieve IWC results in large uncertainties. Particle size distribution is the primary cause for the uncertainty in the retrieved IWC at radar wavelengths, though particle shape and orientation also play significant roles. Particularly in this study, we demonstrate that using both transmitted waves through the clouds (extinction) and backscattered waves from the clouds to retrieve the mean particle size and then using the mean particle size for IWC retrieval reduces the uncertainty. IWC retrieval can be improved with size distribution derived from dual wavelength cloud radar.