On the hourly contribution of global cloud-to-ground lightning activity tothe atmospheric electric field in the Antarctic during December 1992

ELF magnetic field measurements from 10 to 135 Hz at Arrival Heights, Antar ctica, are used as a proxy measure of global cloud-to-ground lightning acti vity. Simultaneous hourly recordings of the atmospheric electric field on t he surface of the Earth at South Pole during December 1992 make possible a detailed comparison between global cloud-to-ground lightning activity and t he atmospheric electric field, Although the mean diurnal variation of the E LF magnetic field anti the atmospheric electric field exhibit a remarkable similarity in shape and phase, the hourly departures from their mean diurna l variations are poorly correlated. We quantify the variability of the atmo spheric electric held which can be explained by global cloud-to-ground ligh tning activity through linear regression analysis. To estimate an accuracy of this method, it is applied to simultaneous measurements of the ELF magne tic field at Sondrestromfjord, Greenland, for comparison. The resulting hou rly contribution of global cloud-to-ground lightning activity to the atmosp heric electric held in the Antarctic during December 1992 is similar to 40 +/- 10%, and the contribution of global cloud-to-ground lightning activity to hourly departures from the mean diurnal variation of the atmospheric ele ctric field is similar to 25 +/- 10%. (C) 1999 Elsevier Science Ltd. All ri ghts reserved.