Evaluation of the LLS efficiency effects on the ground flash density, using the Italian lightning detection system SIRF

The Italian Lightning Detection System started at the end of 1994 and has been recording lightning data since then. The efficiency of the whole network is evaluated with the usual projection software. Considering this projection as the real efficiency is possible to weight the calculated ground flash density, getting a much more significant estimation of this fundamental parameter. At the end of 1999 four sensors were added to the network to increase the detection efficiency over the Southern part of the Italian territory and over the main islands of Sardinia and Sicily. An extrapolation of the network upgrade was performed on the previous years of data using the same efficiency correction method. We developed a dedicated software, which takes into account the real behavior of each sensor and calculates the efficiency of the network with this information. The efficiency obtained can be used to correct the ground density map, avoiding holes of efficiency due to temporary sensor problems. After the corrections significant changes in the ground flash density map can be seen, showing some areas of high density that were missed in the usual uncorrected mapping of data. This suggests that influence of Lightning Location System efficiency has to be carefully taken into account in ground flash density calculations. (C) 2004 Elsevier B.V. All rights reserved.