Observing Precipitation through Dual-Polarization Radar Measurements

Abstract

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 (Z_DR) 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 Z_DR 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 growth environments.