Ice microphysical retrievals using polarimetric radar data

Description

A novel polarimetric radar method for size distribution retrievals of ice and estimation of ice water content (IWC) has been developed. The technique is based on the combination of three radar variables: radar reflectivity Z, differential reflectivity ZDR (or reflectivity difference ZDP), and specific differential phase KDP. The latter plays a particularly important role because it is proportional to the first moment of size distribution in ice and, therefore, is very sensitive to small sizes of ice particles. It is demonstrated that the estimates of the mean volume diameter Dm, total concentration Nt, and IWC of ice particles obtained from Z and the ratio of ZDP and KDP are robust with respect to the diversity of ice habits, their shapes, orientations, and size distributions. Preliminary testing of the suggested technique using the WSR-88D radar data showed a dramatic contrast between the microphysical properties of ice in mid-latitude continental MCSs observed during the MC3E and PECAN campaigns and the hurricanes Irene, Harvey, and Irma which produced extreme concentrations of very small ice with significant IWC that is almost an order of magnitude higher than the one retrieved from conventional Z – IWC relations. Comparisons of the radar-retrieved size distribution parameters of ice with their in situ aircraft measurements during MC3E and PECAN will be also illustrated in the poster.