The Glaciating Behavior of Small Cumulonimbus Clouds

Abstract

Data gathered during consecutive traverses through summer clouds in southern Missouri have been interpreted to indicate that: (1) the glaciating characteristics of commonly occurring small cumulonimbus clouds in this region are dependent upon the size distribution of the liquid phase prior to the inception of glaciation; (2) clouds having large liquid-water drops rapidly form high concentrations of ice particles regardless of the concentrations of foreign ice-forming nuclei; (3) the ice phase within the clouds does not begin anew; it builds upon the size distribution that has been achieved by the liquid phase and consequently a continuous modification of the particle size distribution within the cloud occurs; and (4) coalescence continues to be a dominant growth mechanism and growth by sublimation essentially is by-passed. The data appear to he compatible with a chain reaction process propagated by the formation of satellite ice particles during the solidification of water drops.