Measurement of Atmospheric Liquid Water by a Ground-based Single-Frequency Microwave Radiometer

Abstract

Analysis of equations governing microwave measurements of vapor and liquid as well as measurements by a dual-frequency radiometer show that liquid water, particularly in winter, can be obtained by a single-frequency microwave radiometer operating at 31.65 GHz. Construction and operation of a single-frequency radiometer is found to be simpler and with fewer operational problems compared to a dual-frequency system. The simplicity of the single-frequency system applies to the microwave components, the supporting electronics, the antenna system, the ice-water clearing system, and the positioning system for azimuth and elevation scanning. All of these factors contribute to achieving a reliable and cost-effective measuring system.