Characteristics of Storm Activity and Parameters of Lightning Discharges in the South of the European Part of Russia

Resumo

The results of instrumental studies of storm activity and parameters of lightning discharges in the south of the European part of the Russian Federation are presented. The features of spatial and temporal variations of thunderstorms and lightning parameters within a radius of 650000 km around the center of the lightning- detection network of the High-Mountain Geophysical Institute (Nalchik) covering the North Caucasus and the Black Sea coast are considered. The total number of thunderstorm days per year on the territory in question is approximately 239. The specific lightning susceptibility of the ground surface is approximately 6 discharges/km² per year in the south and 2 discharges/km² per year in the north. The share of terrestrial lightning discharges (positive and negative) on the territory is 12% of the total number of lightning; the share of cloud and intercloud discharges is 88%. According to these data, the share of positive discharges accounts for about 23% of the total number of the “cloud-to-ground” discharges. The average value of the electric currents is 13.5 kA in the negative lightning and 10.6 kA in the positive lightning. The parameters of lightning discharges over mountain terrain (altitude more than 1000 m) and over flatland terrain (altitude less than 1000 m) are considered separately. It has been found that the mean amplitude of the electric current of lightning discharges (regardless of polarity) amounts to approximately 9.29 kA over the flatland regions of the North Caucasus and 11.24 kA in the mountain part; the median value of the amplitude of the electric current reaches approximately 6.56 kA over the flatland terrain and 7.99 kA over the mountain terrain.