Comparison between South African lightning detection network interpretation of single-channel and branched upward lightning flashes to a tall structure

Lightning flashes photographed attaching to the Brixton tower in Johannesburg, South Africa over the period of 2010-2011 are put into two different categories: branched upward flashes and single-channel flashes. Using time-correlation methods, South African Lightning Detection (SALDN) records are matched to the photographed flashes. The SALDN interpretation of the two categories is then evaluated. It is found that the SALDN detected 25% of the photographed branched upward flashes and 44% of the photographed single-channel flashes. Strokes from both categories have location errors with 2 km. Only the branched upward flashes have detected strokes with location errors greater than 2 km. This is attributed to the smaller peak currents measured by the SALDN for branched upward strokes meaning fewer sensors are able to detect strokes from these events resulting in larger location errors.