Comments on “Large Peak Current Cloud-to-Ground Lightning Flashes during the Summer Months in the Contiguous United States”

Abstract

The recent paper by Lyons et al. (1998) reports on large peak current lightning flashes recorded by the National Lightning Detection Network (NLDN) during 14 summer months in four years, 1991–95. Lyons et al. examine, arbitrarily, only flashes with peak currents higher than 75 kA. It is an important contribution. High peak current flashes of positive polarity, for example, have been shown to be associated with sprites and elves in the stratosphere and mesosphere. The purpose of this note, however, is to emphasize that ground truth for negative return stroke peak currents exists only up to 60 kA and this is for triggered lightning (Idone et al. 1993, Table 1). No ground truth exists for return stroke positive peak currents. Despite this problem, we are still justified in making peak current estimates as long as the limitations are recognized. I quote from Lyons et al. (1998, p. 2227) and add explanatory comments: