PARTICULATE COUNTS IN NATURAL CLOUDS AND FOGS

Abstract

Measurements of droplet count have been made in fogs, natural clouds, and laboratory clouds. All droplets larger than 0.75-micron radius that were contained in a small volume (approximately 1 cubic centimeter) of the cloud were included in the sample. Droplet counts measured in radiation fog in the Washington, D. C., area were found to range between 30 and 60 droplets per cubic centimeter. Samples taken at elevated surface locations in low-level clouds ranged from 100 to 500 droplets per cubic centimeter.