Electromagnetic fields associated with lightning discharges in winter

Abstract

Observation of electric and magnetic fields associated with lightning discharges has contributed much to reveal odd characteristics of winter lightning and to clarify part of its substance. The characteristics include high proportion of positive cloud-to-ground flashes among all the ground flashes, frequent occurrence of upward discharges even from structures of less than 50 m in height, and larger average charge amounts neutralized by ground flashes than in summer. Knowledge obtained so far from observations of quasi-static field, wideband electromagnetic field waveforms in VLF to LF frequency range, and VHF radiation associated with lightning discharges in winter is reviewed. © 2007 The Institute of Electrical Engineers of Japan.