Evaluations of Particle Scattering Models for Falling Snow

Monday, 15 December 2014
George Duffy1, Stephen W Nesbitt1 and Greg M McFarquhar2, (1)University of Illinois at Urbana Champaign, Atmospheric Sciences, Urbana, IL, United States, (2)Univ Illinois, Urbana, IL, United States
Several millimeter wavelength scattering models have been developed over the past decade that could potentially be more accurate than the standard “soft sphere” model, a model with is used in GPM algorithms to retrieve snowfall precipitation rates from dual frequency radar measurements. Results from the GCPEx mission, a GPM Ground Validation experiment that flew HVPS and CIP particle imaging probes through snowstorms within fields of Ku/Ka band reflectivity, provide the data necessary to evaluate simulations of non-Rayleigh reflectivity against measured values. This research uses T-Matrix spheroid, RGA spheroid, and Mie Sphere simulations, as well as variations on axial ratio and diameter-density relationships, to quantify the merits and errors of different forward simulation strategies.