HR: 1330h
AN: AE32A-0163    [PDF]
TI: Cloud-to-Ground Lightning and Surface Rainfall During Warm-Season Thunderstorms in Florida
AU: * Gungle, B
EM: bgungle@usgs.gov
AF: Inst of Atmospheric Physics, University of Arizona, Tucson, AZ 85721-0081
AB: Relationships between cloud-to-ground (CG) lightning and surface rainfall have been studied in 9 isolated, warm-season thunderstorms near the Florida seacoast. Counts of CG lightning flashes and the associated rain volumes were measured as a function of time in storm-centered reference frames that followed each storm over a network of rain gauges. Values of the storm-integrated rain volume per CG flash range from 6.6 x 10**3 to 6.4 x 10**4 cubic meters per CG flash, with a mean and standard deviation of 2.4 x 10**4 ñ 2.1 x 10**4. Lag correlation analyses (using 5 minute bins) between the CG lightning and rainfall rates show that the peak rainfall followed the lightning (positive lag) by 0 to 20 minutes in 7 storms, and 2 storms showed no significant lag. A plot of the optimum precipitation lag (in the 7 storms that had a positive lag) vs. the total number of CG flashes shows a linear trend (R2 = 0.78), a result that suggests storms with more CG flashes have longer lags, but our statistics are limited. A plot of the lagged rain volume vs. the concurrent CG flashes in all storms shows a linear correlation (R2 = 0.81) with a slope that corresponds to 1.6 x 10**4 cubic meters per CG flash. We conclude that warm-season thunderstorms in Florida produce a relatively constant precipitation volume per CG flash, and that CG lightning can be used as a proxy for the location and intensity of convective rainfall in that weather regime.
DE: 1854 Precipitation (3354)
DE: 3324 Lightning
DE: 3354 Precipitation (1854)
SC: Atmospheric and Space Electricity [AE]
MN: 2003 Fall Meeting