An empirical model for near millimeter wave snow extinction and backscatter

A snow extinction and backscatter model for near millimeter waves was developed to complete a set of natural atmosphere propagation models for inclusion in the Electro-Optics System Effects Library (EOSAEL). This model is compact, simple, fast, and uses commonly available meteorological data as inputs. The accuracy is commensurate with the accuracy of those input parameters; where the input parameters do not properly characterize the environment, further input specification is available. For snow, the rain equivalent accumulation rate is the fundamental input, with air temperature providing the distinction between dry and wet snowtypes. For millimeter wave (MMW), the classification of the snowflake by its ice-to-liquid-water ratio is necessary, due to the large differences in the complex indices of refraction of ice and water. The snow extinction is presented first, including a review of the data used to generate it. The backscatter model is then discussed, followed by a comparison between the model and measurements made at the Cold Regions Research and Engineering Laboratory (CRREL) SNOW-ONE test in January-February 1982.