Some Remarks on Modeling of the Early Stage of Cloud Formation in a Simulation Chamber

Abstract

A numerical model has been developed to describe the early stage of cloud formation in a relatively small simulation chamber. The results for adiabatic expansion show a tendency for the cloud droplet spectrum to narrow, similar to the results obtained by other authors. The influence of updraft fluctuations is not as important as the fluctuation of temperature which depends upon the amplitude and frequency of the fluctuations, and the expansion rate of volume. Simple models of the sedimentation of the drops show that sedimentation might be a factor limiting the rate of expansion. Nuclei suddenly introduced into the cloud parcel indicate that the seeding effect depends significantly on the concentration and size of predominantly larger nuclei.