Reports on Experiments with Artificial Cloud Nucleation

Abstract

Possibilities for modification and control of certain small scale weather phenomena were clearly demonstrated in 1938 by Houghton and Radford [1] who dissolved local fogs by sprinkling them with hygroscopic substances. Wider possibilities for modification and control of larger scale phenomena became discernible in 1946 as a result of Schaefer’s experiment [2] in which it was shown that the injection of particles of solid carbon dioxide (dry ice) into a laboratory cloud chamber was capable of converting a subcooled water cloud into an ice crystal cloud. On the basis of the available knowledge of the natural rain-producing processes at that time (i.e., the Bergeron effect), it was reasonable to conclude that, in principle, suitably constituted clouds could be induced to release precipitation by artificial nucleation. It remained, however, to determine whether the effect on natural clouds would be sufficiently large to be of practical value.