Non-uniformity of spatiotemporal distribution of annual thunderstorm days in Henan Province

Using the data of annual thunderstorm days from 97 stations in Henan Province during 1960-2000,the spatial and temporal non-uniformity of thunderstorm in the province was analyzed.The results show that mean annual thunderstorm day in Henan Province is 24.9d,and has an obvious decreasing trend. The skewness(sharpness) coefficients of thunderstorm days among stations,which have a distinct annual variance,is negative(positive) for the 80%(60%) years.There are visible correlation between mean thunderstorm days and its standardized variance,which can pass the significance test at 0.001 confidence level.Thunderstorm days in all stations except Xinyang station obey the normal distribution.