Electric field values observed near lightning flash initiations
Article first published online: 20 FEB 2007
Copyright 2007 by the American Geophysical Union.
Geophysical Research Letters
Volume 34, Issue 4, February 2007
How to Cite
2007), Electric field values observed near lightning flash initiations, Geophys. Res. Lett., 34, L04804, doi:10.1029/2006GL028777., , , , , and (
- Issue published online: 20 FEB 2007
- Article first published online: 20 FEB 2007
- Manuscript Accepted: 17 JAN 2007
- Manuscript Revised: 6 DEC 2006
- Manuscript Received: 14 NOV 2006
- runaway breakdown;
- thunderstorm electric field
 From a dataset of about 250 soundings of electric field (E), nine were adversely affected by lightning. These soundings are interpreted as ending near lightning initiation locations. Scaled to standard pressure, the largest observed E was 626 kV m−1 and the largest estimated E was 929 kV m−1. E exceeded runaway breakdown threshold, RBth, by factors of 1.1–3.3 before each flash, and overvoltages were 1.4–4.3. Seven cases had rapid E increases (rates of 11–100 kV m−1 s−1) in the few seconds before the flash, and in three the maximum E occurred 3 s or more before the flash. A tenth sounding with E > RBth for 38 s had subsequent lightning initiate 2 km from the balloon; one channel came within 400 m, but the flash and large E did not adversely affect the instruments. The findings suggest that E > RBth is a necessary condition for lightning initiation, but it is not sufficient.