VLF signatures of ionospheric perturbations caused by lightning discharges in an underlying and moving thunderstorm

Abstract

A sequence of VLF events (first of early/fast type, then of LEP type), observed at Poitiers on the amplitude of the signal from the GQD/19.02 kHz transmitter in England, is analysed. VLF data, sampled at 100 ms intervals, are combined with sferics and METEORAGE data on lightning ground strikes detected within a ±50 km belt centered on the VLF path. Both the slowly and rapidly recovering early/fast events are observed in association with intense positive CG flashes, located in the Baie de Seine (L=2.25), at a distance less than 35 km from the VLF path. The LEP events are observed when the storm, initially overlapping the path, moves southeastwards. Some early/fast events are also observed on the very short path HWU/18.3 kHzPoitiers. Copyright 1998 by the American Geophysical Union.