Wet ice cloud particles at subfreezing temperatures?

Relations between differential reflectivity, ZDR, and the copolar correlation coefficient, Rhv, for ice cloud particles of arbitrary shapes are considered. It is shown that values of ZDR and Rhv for dry ice occupy certain domains. If ZDR and Rhv fall out from the domains, ice hydrometeors contain water.

Radar data collected with the S-band dual-polarization WSR-88D KOUN are analyzed. Examples of areas with ZDR and Rhv out of the domains are demonstrated. Such cloud areas lie at subfreezing temperatures. A conclusion that the areas contain wet ice particles is made. The cloud conditions in these areas are discussed.

Probability of icing for an airplane flying in zones with ZDR and Rhv out of the domains is high. Radar capability to detect zones of icing is discussed.