Evaluation of the South African lightning detection network using photographed tall tower lightning events from 2009 – 2013

The performance characteristics of the South African Lightning Detection Network (SALDN) are evaluated using photographed lightning attachments to a tall structure over a four year period (2009-2013) after increased numbers (19 to 24) and repositioning of sensors in 2011. The structure is not instrumented and the evaluation only focuses on flash detection efficiency and location accuracy. During the four year period, 66 flashes to the tower were photographed and 185 negative SALDN strokes in 39 flashes were time-correlated with the photographs. It is seen that the flash detection efficiency increased from 50% to 76% after the upgrade with this being considered a low estimate given the majority of events are upward in nature. The median location accuracy is found to be 280 m and maximum location error is decreased after the upgrade.