On the Determination of the Flash Detection Efficiency of Lightning Location Systems Given Their Stroke Detection Efficiency

A number of lightning detection systems have been installed around the world and are currently being used to gather lightning density and current amplitude statistics. These data are being used to question the universality of Berger’s statistics, and attempts to re-examine the currently used lightning protection standards can be expected. It is therefore important that these complex lightning location systems and their output be well understood. A lightning that reaches the ground is called a ground flash. The most common type of ground flash is composed of a number of separate discharges, each called a stroke. A ground flash can contain from one to tens of strokes. In this paper we investigate the relation between the stroke and the flash detection efficiencies of lightning detection systems and we develop a method that allows for the estimation of the flash detection efficiency once the stroke detection efficiency is known. The method also allows for the estimation of the number of flashes as a function of the number of strokes per flash in a given area. We have applied our technique to the Florida flash distribution by stroke order (which is similar to the distribution measured in South Africa). Our results show that a system’s flash detection efficiency can be appreciably higher than its stroke detection efficiency.