The Phase Change in an Artificial Supercooled Cloud upon Heterogeneous and Homogeneous Nucleation

Abstract

A modified version of the Continuous Small Particle Sampler was used to obtain cloud particle samples of the phase change in a cloud chamber. The effects of silver iodide (AgI) and dry ice (CO2) were studied under similar conditions. Nucleation by AgI produced evidence which followed heterogeneous nucleation theory and crystal growth-rate observations. The dry ice seeding, plus a comparison with natural samples, illustrated Mason's homogeneous nucleation theory. Finally, total water content balances were computed and depict the water content of ice, liquid water content, and water vapor content proportions for each seeding.