A Database of Microwave Single-Scattering Properties for Nonspherical Ice Particles

Abstract

As satellite observations at high microwave frequencies have recently become available, there is an increasing demand for methods that accurately evaluate the single-scattering properties of nonspherical ice particles at these frequencies. Algorithm developers can use the single-scattering datasets in the retrievals of cloud ice water content and snowfall rate. However, the methods that correctly handle the scattering of complex nonspherical particles are computationally inefficient and impractical for physical retrieval algorithms, in which scattering needs to be evaluated many times for particles with various sizes and shapes. As a remedy, during the past several years we have computed the scattering properties?scattering and absorption cross sections, phase functions, asymmetric parameters, and backscattering cross sections?using an accurate discrete dipole approximation method and arranged the results into an easy-to-access database. The database contains the scattering properties at frequencies from 15 to 340 GHz, with temperatures from 0° to ?40°C, of particle sizes (maximum dimension) from 50 to 12,500 ?m, and for 11 particle shapes. The database along with an easy-to-use reading program is now made available to interested investigators. This article explains how this database is derived and how it can be used.