Convected Charge in Thunderstorms

The charge transport within thunderclouds by the convective motions of the cloud is examined. I n the presencc of the primary positive dipole, shielding charge distributions are formed within thc lower and upper cloud boundaries as the result of ion conduction from the free air and ion capture by droplets and precipitation in peripheral cloud layers. Cloud droplets positivcly charged by the conduction current to the cloud basc arc lifted by the updraft into uppcr cloud volumes where they contribute to the positive pole of the primary dipole. I n turn, precipitation developing in thc cloud top carries negative charge to lower cloud levels during fall under gravity forces. The role of water accumulation in the upper cloud is shown to be an important factor in establishing thc non-neutralizing current paths in uppcr cloud layers. The charge transport by the convection mechanism is believed to be a major current flow of storms. The role of other thunderstorm electrification mechanisms is only briefly considered.