Observations of Convective Clouds by Means of Pulsed-Doppler Radar

Abstract

A new pulsed-doppler radar set designed for measuring the vertical distribution of the particle size and vertical-velocity spectra is briefly described. The X-band radar set employs a vertically-pointing antenna producing a 1.3 degree beam. Measurements of the properties of the hydrometeors are made at 500-ft. intervals from 500 ft. to a maximum altitude of 63,000 ft. The intensities of the radar return from particles in each of ten velocity channels are recorded digitally. The analysis of echo returns from showers is discussed in some detail. The data allow inferences of the change of particle size as a function of altitude and time, as well as of the vertical air motions in the cloud. New observations of so-called "angel echoes" are presented. Most often the vertical velocities of the angel echoes were positive. These observations can be used to infer information about clear air convection.