On Parametrization of Microphysical Processes of Electrification in a Three-Phase Model of a Convective Cloud

N. E. Veremey, Yu. A. Dovgalyuk, and V. N. Morozov

For constructing a three-dimensional model of a convective thundercloud, an important task is to include elementary mechanisms of electrification of cloud particles, which lead to the formation of spatially extended electric charge structures and large-scale electric fields in the cloud. Methods of parametrization of microphysical processes of electrification of cloud and precipitation particles (droplets, ice crystals, hail, and graupel), attributed to the mechanism connected with collisions between particles in different phase states and their separation, are reviewed. Expressions for the generation rate of electric charges are discussed which are based both on the parametric description, when distribution functions of cloud and precipitation particles are initially prescribed with respect to radii (or masses) and on a detailed microphysical description, when particle distribution functions are determined from a numerical modeling of microphysical cloud processes.