The Evaluaton of Models for Atmospheric Attenuation and Backscatter Characteristic Estimation at 95 GHz

摘要

Active or passive observations of targets on the surface of the earth at a frequency of 95 GHz may be adversely affected by the presence of rain or cloud along the observation path, in the vicinity of the target, or above the target. The effects of rain or cloud on system performance may be simulated given the characterstics of the system and models for attenuation and scattering by the rain or cloud particles. The validity of the simulation results depends upon the veracity of the rain or cloud model. In this brief report, models for attenuation and scattering by rain are reviewed and compared with experimental observations. Models for the calcualtion of attenuation due to clouds and the clear atmosphere are also presented. Calculations of the scattering properties of rain drops have been made many times over the past four decades. The results of these calculations have been used to model attenuation effects for radar and communication systems and to calibrate weather radar systems for use in measuring rainfall. The adequacy of the calculations for the estimation of attenuation over a wide frequency range has received considerable attention. (Author)