Climatic Characteristics Of Thunderstorm In Shanxi Province And Related Circulation Variations Background Analysis

The spatial anomaly modes of thunderstorm in ShanXi province and the relation between modesand largeseale circulation are analysed in emphasis on the basis of the basal climatic characteranalysis of thunderstorm in ShanXi province, by using the thunderstorm observation data of 69weather station from 1971 to 2004 in Shanii and the NCEP/NCAR reanalysis data. The main resultsare as follows:Seasonal change characteristic of thunderstorm day is extremely obvious in Shanxi province.The thunderstorm mainly occurs in May to September. There are obvious differences in differentmonths, July is the month with the highest probability of thunderstorm day.In the recent thirty-four years, the accordant anomaly is the most important mode of spatialanomaly in ShanXi and the antiphase change between southern and northern part of ShanXi is alsothe significant mode.Against the summer thunderstorm anomaly, ShanXi province could be partition off to fourparts. In summer, decreasing tendency of thunderstorm frequency is remarkable at basin in Southand North ShanXi, yet that is not notable in other areas.There are marked negative correlations between thunderstorm anomaly in north and the anomalyof circulation(Ural blocking high) in middle and high latitude and between thunderstorm anomalyin south pan and the circumfluence anomaly(subtropical anticyclone in the west part of PacificOcean) in subtropic.Thunderstorm day anomaly of the North region is associated directly with the Northwest vaporinflow flux. And the basin of South is associated directly with the Southwest vapor inflow flux.