Electric field at the ground in a large tornado
Article first published online: 21 SEP 2012
Copyright 2000 by the American Geophysical Union.
Journal of Geophysical Research: Atmospheres (1984–2012)
Volume 105, Issue D15, pages 20145–20153, 16 August 2000
How to Cite
2000), Electric field at the ground in a large tornado, J. Geophys. Res., 105(D15), 20145–20153, doi:10.1029/2000JD900215., , and (
- Issue published online: 21 SEP 2012
- Article first published online: 21 SEP 2012
- Manuscript Accepted: 28 MAR 2000
- Manuscript Received: 20 SEP 1999
A number of observers have reported lightning, diffuse luminosity, or other manifestations of electrical activity in tornadoes. To try to quantify these observations, eight instruments with sensors for electric field and other parameters were placed in front of a large tornado that passed by Allison, Texas, on June 8, 1995. The edge of the tornado vortex passed over two of the instruments and near other instruments. When the two instruments were in the low-pressure region near the edge of the vortex, they indicated electric field amplitudes less than about 3 kV/m, which is low compared with amplitudes of 10 kV/m or greater that are often present below thunderclouds. The thunderstorm produced frequent lightning, but there is no evidence from the measurements or from visual observations of lightning in the vortex. However, there was one interesting electrical effect associated with the tornado: the electric field at the two instruments in the vortex relaxed to zero quickly after lightning flashes, whereas the electric field at nearby instruments outside the vortex did not relax quickly after the same lightning flashes. The most likely cause of the rapid relaxation is shielding of the electric field at the ground by charge induced on soil, leaves, grass, and other debris lofted by the strong winds.