In situ measurements of contributions to the global electrical circuit by a thunderstorm in southeastern Brazil

Article history: Received 11 December 2007 Accepted 27 March 2008 The global electrical circuit, which maintains a potential of about 280 kV between the earth and the ionosphere, is thought to be driven mainly by thunderstorms and lightning. However, very few in situ measurements of electrical current above thunderstorms have been successfully obtained. In this paper, we present dc to very low frequency electric fields and atmospheric conductivity measured in the stratosphere (30–35 km altitude) above an active thunderstorm in southeastern Brazil. From these measurements, we estimate the mean quasi-static conduction current during the storm period to be 2.5±1.25 A. Additionally, we examine the transient conduction currents following a large positive cloud-to-ground (+CG) lightning flash and typical −CG flashes. We find that the majority of the total current is attributed to the quasistatic thundercloud charge, rather than lightning, which supports the classical Wilson model for the global electrical circuit. Published by Elsevier B.V.