Convective versus stratiform rainfall: an ice-microphysical and kinematic conceptual model

The vertical profiles of latent heat released to the atmosphere are distinctly different between the two basic modes (convective and stratiform) of precipitation. Triggered by climatological studies focused on the heating of the atmosphere, but also by aspects relevant for radar-rainfall measurement, hydrologic modeling, and parameterizing different types of rainfall in large-scale and global circulation models, the discussion of convective vs. stratiform rainfall has gained increased attention. In that light, the kinematic and microphysical aspects of precipitation formation are revisited and a conceptual model introduced that provides a basis for an improved understanding of differences observed in convective and stratiform rainfall. The existence of higher-density ice particles is indicative for a convective nature of precipitation. Graupel may be considered as particles marking the boundary between convective and stratiform precipitation. The growth of higher-density graupel particles requires updrafts of the order of 2-3 m/s, which is in support of classifications commonly advocated.