The Modification of Joint Size–Charge Distribution in Rain. Part I: Computations which Exclude Partial Coalescence

Abstract

The effect of individual charge-modifying processes is tested by following the development joint distributions of raindrop size and charge through a fall depth of 1 km beneath a weakly electrified warm cloud. Evaporation, ion capture and coalescence all cause the small-drop charge distribution to become narrower and any initially skewed distribution to become more symmetrical. Ion capture does not result in substantial negative charging unless the initial charge distribution is very narrow. Ion diffusion charging is found not to be significant.