Average Diurnal Variation of Summer Lightning over the Floirida Peninsula

Abstract

Data derived from a large network of electric field mills have been used to determine the average diurnal variation of lightning in a Florida seacoast environment. These data were obtained at the NASA Kennedy Space Center (KSC) and the Cape Canaveral Air Force Station (CCAFS) during the summers of 1976–78 and 1980 and they show a peak in lightning activity between the hours of 2000 and 2100 GMT or about 3 hours after local solar noon. When the statistics of lightning am compared with the statisfies or thunder on the same day, good agreement is round between the start times and the times of peak activity; however, the thunder stop times tend to Rag the lightning by 1 to 2 hours. The average diurnal variation of cloud-to-ground lightning that was recorded by a network of magnetic diffusion-finders covering the entire South Florida region during the summer of 1978 is in good agreement with the results obtained at KSC and CCAFS and agrees with previous estimates of the time variations in rainfall and the rainfall rate over South Florida. The South Florida lightning data also show substantially less diurnal variation over the Atlantic Ocean and Gulf of Mexico than over the land. The implications of these results for the detection of lightning at local midnight dawn and dusk by a DMSP (Defense Meteorological Satellite Program) satellite are discussed.