Identification of Rain and Hail with Circular Polarization Radar

Abstract This study integrates surface hail reports with concurrent radar measurements. It employs polarization techniques, corrected for propagation effects, to detect hail within rain storms. For two decades, S-band polarization diversity radar was employed in central Alberta, Canada, to study severe storms. The radar normally transmitted circularly polarized radiation. It measured the four parameters commonly used to describe echoes received by circularly polarized weather radars: namely, equivalent reflectivity factor Ze, circular depolarization ratio CDR, degree of common hydrometcor alignment ORTT, and their apparent orientation angle ALD. It was shown that circular polarization estimates of differential reflectivity ZDRc are comparable to those more commonly derived using dual-linear polarization radars. Low-level radar measurements were compared to well documented and carefully timed ground-based observations of precipitation collected by a mobile truck crew. The case studies were analyzed to esta...