Observing Precipitation through Dual-Polarization Radar Measurements

Dual-polarization radar measurements of precipitation are primarily influenced by the size, shape, orientation, and phase of scattering hydrometeors. As a result, these measurements can serve as a tool for remote identification of hydrometeor characteristics. This paper presents an overview of the definitions, observed values, and applications of differential reflectivity (ZDR) and linear depolarization ratio (LDR) measurements. Brief examples of these measurements are given for widespread stratiform precipitation, a rapidly developing convective cell, and a severe hailstorm. The results outline the role that ZDR can play in the differentiation of rain and solid precipitation, identification of supercooled raindrops above the 0°C level, and identification of hail at the surface. LDR measurements are seen to reveal contrasts in ice-particle shape, orientation, and particle phase. These contrasts are of particular benefit toward delineation of hail regions aloft and identification of mixed-phase particle gr...