Analysis of abnormal high temperature in Southwest China in 2006

An abnormal high temperature took place in eastern Sichuan and Chongqing in 2006.The high-temperature periods from 1948 to 2006 are screened with temperature greater than 25.5 degrees Centigrade and at least lasting for three days in July and August.The results show that the frequency of high temperature is higher since 1990s such as in 2002,2003 and 2006.The high temperature in 2006 is studied.The monthly mean temperature is high,which occurs earlier and wider with much more days of high temperature.It has quasi-20-year period and in 2006 it attains the peak.The westward,northward advance of the Subtropical High results in the high temperature.That the center of the Continental High lies northward and eastward is one of these reasons.Moreover,the snow depth and snow cover days over the Qinghai-Tibet Plateau,especially in spring,can also influence the temperature in southwest China.There is an obvious negative correlation between the snow cover and the temperature in southwest China.