Lightning and Climate: a Review

INTRODUCTION The importance of lightning for climate studies is increasingly recognized. Thunderstorms are major players in the global redistribution of water substance, a key mediator of both short and long wavelength radiation. The cloud buoyancy that drives vertical motion in electrified convection is of the order of 1 C. Temperature perturbations of this order have appreciable local effects in the highly nonlinear process of cloud electrification. Temperature perturbations of this order are also clearly important in the context of global warming. The global circuit framework has been in place for decades but the ability to measure it reliably has developed only recently. New measurements from the ground and from space have greatly stimulated the application and integration of lightning in climate studies. Areas treated in this review include the relationship of lightning and rainfall in the general circulation of the atmosphere, the manifestation of tropical “chimneys” in the lightning activity, the dependence of lightning activity on temperature, the candidacy of thunderstorms and lightning as climate “extremes”, the connection between lightning and upper tropospheric water vapor, the increasingly investigated role of aerosol in precipitation and electrification processes, the regional climatology of lightning, and finally the issue of long-term variations. Space limitations have prevented the use of illustrations and the inclusion of a reference list.