Climate Characteristics of Thunderstorm in Sichuan in Recent 54 Years

With composition analysis，wavelets analysis and trend analysis methods adopted，the spatial and temporal variation，initial and ending dates of thunderstorms was analyzed for 154 stations in Sichuan region during the period 1960－2013．The research results show that the annual thunderstorm day is much more in the west of Sichuan region than in the east，and has a quasi-periodic oscillation of 11 years．It also displays a decrease situation，remarkable decrease in the northwest of Ganzi，north of Aba，west of Panzhihua and Liangshan．Overall，the highest proportion of thunder occurrence occurs from the last tenday of June to the last ten-day of August，but it's earlier in western Sichuan Plateau and later in the south and midland Sichuan basin．Meanwhile thunderstorm appears more in the time from the afternoon to wee hours，but thunderstorm events peak from 14:00 to 20:00 in western Sichuan Plateau and southwest Sichuan mountain region．In addition，the initial(or ending) dates of thunderstorms became earlier obviously in southwest Sichuan mountain region and Litang(or in Bazhong，Dazhou，Nanchong，Guang'an，Guangyuan，Mianyang) ．As a whole，the period of annual thunderstorm is shortened in Guangyuan，Bazhong，Dazhou，Luzhou and Liangshan．