Charge transfer to the ionosphere and to the ground during thunderstorms

This study examines the current that is driven to the ionosphere and to the ground before, during and after single negative cloud-to-ground (CG) and intracloud (IC) lightning discharges. A numerical model has been developed, that calculates the quasi-electrostatic field before the lightning, due to the slow accumulation of the charge in the thundercloud, and after the lightning by taking into account the Maxwellian relaxation of charges in conducting atmosphere and accounting for the dissipation stage of the thunderstorm development. From these results, the charges that are transferred to the ionosphere and to the ground are calculated. We demonstrate the significance of considering the pre-lightning and the dissipation stages and accounting for realistic distribution of the conductivity inside of the thundercloud for the accurate calculation of the charge flow to the ionosphere and to the ground. We show that the charge transfer to the ionosphere depends mainly on the altitudes of the charges inside of the thundercloud and on their spatial separation. The amount of charge that is transferred to the ground, due to currents flowing in the vicinity of the thundercloud during a transient time period following a lightning discharge, is significantly affected by the conductivity distribution in the thundercloud and can be several times smaller than the amount of charge that is transferred to the ionosphere during the same time period.