Improvements in the detection efficiency model for the Brazilian lightning detection network (BrasilDAT)

The detection efficiency (DE) is the most important performance gauge of a lightning detection network (LDN). Moreover, the main motivation for evaluating the DE of a LDN is to separate the geographical variations of the CG lightning parameters from the variations regarding the network performance. A review of previous relative DE techniques and simple methods to correct the cloud-to-ground (CG) lightning flash density maps is presented. In addition, recent improvements in the flash DE model for the Brazilian lightning detection network (BrasilDAT) are discussed. The DE estimated values are based on the sensor individual DE probability functions, which are derived from a large amount of CG stroke data provided by the network considering different distances from the sensor and specific peak current ranges. The new approach provides better results when compared with the previous developments, since the calculation of the sensor DE probability functions neglects the lightning data provided by the minimum number of reporting sensors. Hence it is possible to minimize the unrealistic enhancement of the DE closer to the network boundaries (“border effect”) without affecting significantly the performance inside the network. The main result is a more realistic correction of the CG flash density maps, particularly at the outermost network areas, leading to an improvement in the model sensitivity.