EarthRef.org Reference Database (ERR)
Development and Maintenance by the EarthRef.org Database Team

Detailed Reference Information
Thottappillil et al. 1990
Thottappillil, R., Rakov, V.A. and Uman, M.A. (1990). K and M changes in close lightning ground flashes in Florida. Journal of Geophysical Research 95. doi: 10.1029/90JD01294. issn: 0148-0227.

Electric field changes produced by K and M processes in Florida lightning ground flashes at distances within 12 km are analyzed and compared. The geometric-mean time durations were similar: 0.7 ms for 135 K changes and 0.9 ms for 80 M changes. The geometric-time intervals between events were dissimilar: 12.5 ms for 93 K change intervals and 2.1 ms for 48 M change intervals. Our geometric mean K change interval is about twice the median value observed by Kitagawa et al. (1962) in New Mexico who used a somewhat different measurement technique, while our geometric mean M change interval is about one-third the New Mexico median value although Kitagawa et al. (1962) apparaently excluded from their statistical data those M components occurring within 15 ms of the return stroke initial peak field, and we included these. The K electric field changes were not always simple ramps superimposed on the slower interstroke J or final F field changes, but, rather, could be grouped into four general waveshape categories.

All M field changes had relatively similar hooked shapes. We argue that the hypothesis proposed by Kitagawa et al. (1962) that K and M processes are essentially the same physical phenomenon is not supported by our data, although it cannot be positively ruled out; and, additionally, that the conclusion of Kitagawa and Brook (1960) that the net interstroke field change (J change) is essentially the sum of the individual K changes is also not supported by our data. Further, our data suggest that there is a significantly higher upper limit for the moment change associated with K processes in ground flashes than the 1 to 2 C-km reported by Brook and Kitagawa (1960) and Ogawa and Brook (1964). ¿American Geophysical Union 1990

BACKGROUND DATA FILES

Abstract

Keywords
Meteorology and Atmospheric Dynamics, Lightning
Journal
Journal of Geophysical Research
http://www.agu.org/journals/jb/
Publisher
American Geophysical Union
2000 Florida Avenue N.W.
Washington, D.C. 20009-1277
USA
1-202-462-6900
1-202-328-0566
service@agu.org
Click to clear formClick to return to previous pageClick to submit