Ions and precipitation charging in warm and cold clouds as simulated in one-dimensional time-dependent models.

One-dimensional time-dependent models of warm and cold clouds were constructed to test the electrical and precipitation development in the presence of a variety of charge separation mechanisms. The models simulate charging by ion diffusion, the Wilson effect (ion conduction), polarization induction, the Workman-Reynolds effect and the thermoelectric effect. It was found that charging by ion processes does not significantly contribute to the electrical development of either warm (shallow or deep) or cold clouds. In cold continental clouds, without ice multiplication processes, charging due to ice-ice collisions did not significantly contribute to the electrical buildup because of the low concentrations of ice particles and their low electrical conductivities at low temperatures.-from Authors