Submicrosecond field variations during the onset of first return strokes in cloud-to-ground lightning

Abstract

Measurements of the electric field E and dE/dt signatures radiated by first return strokes striking seawater in 1985 show that the average peak E and peak dE/dt are 8.6 ± 4.4. V m-1 and 42 ± 13 V m-1 μs-1, range-normalized to 100 km, after correcting for the effects of propagation. The full width at half maximum of the initial half-cycle of dE/dt is 64 ± 22 ns. The corresponding peak current and peak dI/dt, inferred using a simple semiempirical relationship, are 29 ± 15 kA and 105 ± 34 kA μs-1. These results are in good agreement with similar measurements made in 1984.