Polarimetric method for ice water content determination

There have been a number of studies to estimate ice water content (IWC) of snow clouds using the radar reflectivity factor, Z. All of these studies show extreme variability in the IWC-Z relations, which appear to change from day to day and cloud to cloud. High diversity in the IWC-Z relations is primarily due to the fact that reflectivity factor is proportional to the product of IWC and average mass of ice hydrometeors; therefore at least one more independent measurement is needed to resolve this ambiguity. Since ice and snow hydrometeors are nonspherical the use of polarimetry is a natural way for estimation of bulk properties of snow clouds and precipitation. In this paper the authors develop a radar polarimetric model of a cloud of ice hydrometeors and obtain a polarimetric relation for computing TWC. They account for the diversity of crystal shape and the dependence of shape and density of scatterers on their size. Finally, they use polarimetric data from four Oklahoma snowstorms to check the consistency of the IWC estimates (obtained from the proposed polarimetric algorithm) with those derived using conventional IWC-Z relations