ANALYSES ON CLIMATIC CHARACTERISTICS OF HIGH TEMPERATURE AND CIRCULATION SITUATION IN RECENT 48 YEARS IN CHONGQING CITY

Based on the data of day-to-day maximum temperature during 1960~2007 that recorded by the 23 meteorological stations in Chongqing City and the height field grid data of NCEP/NCAR,exploring EOF and REOF,abnormal spatial distributional features in Chongqing City were studied in detail.A contrast analysis was made of the difference in the large-scale atmospheric circulation between 2006 year,the years with more-than-normal high temperature days and the years with less-than-normal high temperature days from July to August in Chongqing City.The results show that,high temperature weather appears mainly in July and August every year,the high temperature days have obvious chronological and regional distinctions,with the least in 1980 s and the most in 1970 s,besides,the Yangtze River and Wujiang River are the locations with frequent high temperature weather in Chongqing City.The consistently abnormal distribution is the principal spatial mode of high temperature days in Chongqing City;it is found that the spatial mode can be divided into three key areas:they are the Midwest of Chongqing City,the southeast of Chongqing and the northeast of Chongqing City.More-than-normal high temperature weather occurs widely when blocking high is weak from the Ural Mountain to the Okhotsk Sea,East Asia trough is shallow,the South Asia High is more eastward than that in the normal year,the West Pacific Subtropical High is more northward and more westward than that in the normal year,the South Asia High on upper levels superposes on the West Pacific Subtropical High on lower levels.