The Accuracy of Rainfall Rate Measurement by Tunable Millimeter-Wavelength Radar

Abstract

A theoretical and empirical assessment is made of a technique proposed recently for measuring rainfall rate by radar. The technique involves tuning a variable wavelength radar across the millimeter wavelength band to the wavelength where the reflectivity is a maximum. It is shown that the rainfall rate found from the latter wavelength is subject to potentially large errors due to drop size distribution variations and to uncertainty in the measurement of the reflectivity. Other sources of possible large error which are considered include Variations in the size of the pulse volume as the wavelength changes and attenuation due to clouds, gases and precipitation of the short wavelengths involved in the proposed technique.