The Nature and Detectability of Clouds and Precipitation as Determined by 1.25-CENTIMETER Radar.

Abstract A survey is made of the clouds and precipitation detected at a wavelength of 1.25 centimeters. The frequencies of various cloud types and their typical echo characteristics are presented. Within 89 periods during which echoes were received, slightly less than 50 per cent of the echoes could be classed as echoes from internationally defined clouds. Detailed correlation of cloud echoes with the visual clouds present show that, provided each cloud type observed is assigned equal weighting, about 47 per cent of the visual clouds were detectable. The radar characteristics of common cloud types and the conditions favoring radar return from individual types are discussed. With most types, cloud temperature is indicated as being a critical factor governing detectability. This fact and the frequent occurrence of ice-crystal streamers indicate that the presence of ice crystals favors detectability. The detection of certain non-visible clouds is cited, and explanations for their presence are offered. The de...