The precipitation particles mostly form through the ice phase, although raindrops that form by collision and coalescence are observed in some clouds with warmer bases. The clouds typically contain high concentrations of ice in their later stages. It is likely that the Hallett-Mossop process of splintering during riming operates in these clouds and is responsible for the high concentrations of ice that are observed. We have developed a model of this process where ice particles grow in a multi-thermal framework. We find that the rate of glaciation has the strongest dependence on the cloud liquid water content.
Rapid glaciation can occur if adiabatic cores are present.
Blyth, A.M., Benestad, R.E., Krehbiel, P.R., and J. Latham. Carpenter, R.L., K.K. Droegemeier, and A.M. Blyth. Entrainment and Detrainment in Numerically Simulated Cumulus Congestus Clouds. Part I Model Initialization, General Results, and Comparison with Observations. Blyth, A.M., and J. Latham.