Characteristics Analysis on Lightning in Hilly and Mountainous Areas Using Lightning Location System

To study the lightning distrubution characterristis,through using cloud-to-ground lightning data(in 1999-2008) obtained from Chongqing lightning location system,and by means of mathematical statistics,regression analysis,etc.,we focus on the analysis of temporal and elevation attributes of lightning in hilly and mountainous areas above 800m altitude.The results show that: negative lightning frequency in hilly and mountainous areas(95.6%) is significantly higher than positive lightning frequency(4.4%);lightning mainly occurs from April to October,with diurnal distribution having two high frequency periods(0:00-3:00,13:00-16:00),and lightning frequency gradually decreases with the increase of altitude;the proportion of positive lightning and high-amplitude lightning increase sharply with the increase of altitude;the average current intensity of positive lightning is significantly higher than that of negative lightning,and the average lightning current intensity in winter is significantly higher than that in summer;the diurnal variation of the average current intensity of positive lightning has two peaks respectively before dawn and in the forenoon;moreover,the current intensity of positive lightning increases with the increase of altitude.Thereby,the cumulative probability curve of lightning current amplitude in hilly and mountainous areas is obtained,providing a reliable and scientific basis for lightning protection design and construction.