Relation between the near-Earth electric field at high latitudes and intense cloud-to-ground lightning strokes initiating VLF emission bursts

Since 1998, the gradient of the near-Earth atmospheric electric field potential (| Ez |) has been continuously registered at Vostok Antarctic station within the scope of the joint Russian-Australian project. The data of the continuous 10-day period of fine weather in April 1998 have been selected for the following analysis. The field | Ez | behavior at Vostok station was compared with a number of lightning strokes obtained from data of the ground-based network of electromagnetic measurements. It has been found out that the average hourly values of | Ez | evidently negatively correlate with the number of intense lightning strokes. The causes of these relations are discussed. The obtained results are interpreted based on a theory of global electric circuit.