中文摘要：

利用2013年7月中国台站逐日观测资料及1981年1月—2013年7月NCEP/NCAR再分析资料,通过统计以及诊断方法,研究分析2013年7月中国南方异常持续高温成因。结果表明,2013年西北太平洋副热带高压（简称西太副高）在5月就表现出异常的前兆,其特征指数表现出明显偏南、偏西、偏强。7月西太副高强度的高值区一直处于我国江南-台湾海峡一带,这一形势有利于我国南方夏季形成高温酷暑天气;欧亚大陆上空对流层温度的异常持续增加,加剧西太副高变强,有利于西太副高异常状态的持续;在20°S~20°N,100~140°E范围内的南风明显减弱,东太平洋海域上北风明显增加的现象,消弱了该区域热带气旋的生成发展,使得西太副高有机会持续稳定,甚至加强控制我国南方地区。5—7月南亚高压整体偏东,1 660 gpdm特征线表现出异常持续偏东的状态,1 676 gpdm特征线从6月4日开始稳定出现,并表现为整体明显偏东的特征;期间,南亚高压与西太副高呈现出＂相向而行＂与＂背向而斥＂的东西振荡特征;通过7月2—3日个例明显看出,南亚高压的东进过程对西太副高的加强与西进有明显的影响。

英文摘要：

The cause of abnormally persistent high temperature in the south of China in July 2013 was analyzed by statistical and diagnostic methods using the station observational data in July 2013 and the NCEP/NCAR reanalysis data from 1981--2013. Results indicated that the Western Pacific Subtropical High showed abnormal precursor in May 2013 and its characteristics index well pointed to the strengthening and westward and northward extension of the High. There was an advantageous condition for such weather in July： the High strengthened in the area between the south of China and Taiwan straits. As the High strengthened and kept abnormal, temperature increased in the troposphere over Eurasia. The development of the tropical cyclone in Pacific is weakened so that south winds decreased significantly in the region from 20°S-20°N and from 100-140°E and north winds increased noticeably over the East Pacific. As a result, the High was sustainable and stable and even strengthened its control of the southern regions of the country. When the high temperature is abnormally persistent, the South Asia High goes persistently eastward from May to July, and its characteristic 1 660 gpdm contour is also persistently eastward. The characteristic 1 676 gpdm contour persists and goes much eastward from the 4th June. Both the South Asian High and Western Pacific Subtropical High were showing ＂relative motion＂ and ＂reversed motion＂, characteristics of oscillating from east to west during that time. Through a typical case from the 2th to 3rd of July, the eastward progression of South Asian High is found to have impact on the strengthening and westward extension of Western Pacific Subtropical High.