Expression for Critical Radius and Generalization to Consider Spectral Dispersion

Representation of cloud and precipitation processes is crucial for improving atmospheric models of various scales ranging from large eddy simulations (LES) to cloud resolving models (CRMs) to global climate models (GCMs) (Stokes and Schwartz 1994). A key process that must be parameterized is the so-called autoconversion process whereby large cloud droplets collect small ones and become embryonic raindrops (Kessler 1969, Manton and Cotton 1977, Tripoli and Cotton 1980, Liou and Ou 1989, Baker 1993, Boucher et al. 1995, Liu and Daum 2004). Accurate parameterization of this process is especially important for studies of the second indirect aerosol effect (Boucher et al. 1995, Lohmann and Fleichter 1997, Rotstayn 2000).