ROLE OF ATMOSPHERIC IONS IN CLOUD ELECTRIFICATION AND GLOBAL CIRCUIT

Abstract

Thunderclouds are known to generate strong electric fields and produce lightning. Various mechanisms to explain the electrification in clouds have been sugges-ted. These mechanism can be classified into two broad ca teg ori es ( I) The precipitation-powered mechanisms and (2) The convective charging mechanisms. Recently, Wagner and Telford (217) have proposed an ' entrainment mechanism' . In this mechanism, entrainment of cold air at the top of the cloud forms blobs which descend due to negative buoyancy. The conductivity inside the blob is different from that in the surrounding air. The charge is generated due to this inhomogeneity in the conductiity. The identification of a single dominant mechanism or to find a viable combination of more than one such mechanisms for the electrification of the thundercloud in its real conditions, continues to evade the vi gorous pursui t of researchers in this field....