厄尔尼诺与华中夏季低温

根据华中地区10个测站1951－1995年7－8月气温资料，采用EOF、遥相关、全盛分析等统计－天气气候学方法，研究了华中夏季温度变化同北太平洋SSTA场的相关结构及北半球500hpa高度场对海温异常的响应。具体描述了ENSO年和Lanina年华中夏季温度距平的差异性。并通过分析冷夏年500hpa高度场的环流特点，探讨海－气间的可能联系及物理机制。结果表明：北太平洋海温与华中夏季温度存在较好的滞后相关关系。ENSO位相对，华中夏季温度偏低，易出现冷夏，拉尼娜年则相反，易出现酷暑。冷夏（酷暑）对应着赤道东太平洋正（负）SSTA，西太平洋副热带海域负（正）SSTA；反映了赤道东太平洋和热带西太平洋之间存在翘翘板效应。海温异常变化超前副高异常变化1－3个月。冷夏年副高主体偏东偏南。

ENSO AND THE LOWER TEMPERATURE IN HUAZHONG REGION IN SUMMER

According to the mean temperature data in July and August of summer from ten observation stations in Huazhong region during 1951 to 1995, this paper dealed with the correlation structure of the summer temperature in Huazhong with SSTA in northern Pacific by the statistics -- weather and climate method of an empirical orthogonal function(EOF), teleconnection and competition analysis, ect. The monthly mean 500hpa geopotential height of the northern hemisphere responses to SSTA anomaly and the possible influence of physical processes by analysing the circulation character of 500hpa in cold summer is disscussed. It reveals the better lag connection relationship between the summer temperature in Huazhong and SSTA in northern Pacific. The obvious influence of summer temperature departure in Huazhong in ENSO years and in Lanina years is described. The results show that the cold summer usually occurs during ENSO episode, with positive SSTA in the equatorial eastern Pacific and negative SSTA in the western tonical Pacific. It reflects the seesaw relation between the equatorial eastern Pacific and the western tropical Pacific, and vice rersa. The position of subtropical high southward and eastward may lead to the cold summer in Huazhong.