南疆夏季异常高温的气候背景分析

利用1951-2005年若羌、且末及和田3个代表站55 a气温和北半球500 hPa高度及北太平洋海温资料,分析了南疆地区夏季高温年的气候变化,并对其形成进行海温场背景分析。发现南疆地区夏季高温的形成与北半球大气环流和北太平洋海温异常变化相联系。前期10月和2月相关的北半球副高特征指数对南疆地区夏季温度有很好的指示性;南疆地区夏季高温年发生的前期1月份开始,即在北太平洋建立西南海区高东北海区低的海温距平分布型,这种分布型持续到5月份结束。但这2个海区前期海温的异常变化不同,表现为:1-2月份西南海区海温变化幅度小,东北海区海温变化幅度大。3-5月份则西南海区海温变化幅度大,东北海区海温变化幅度小。

Climatic Background Analysis of Abnormal Summer High Temperature in Southern Xinjiang

Based on the data of sea temperature of North Pacific,500 hPa geopotential height over the North Hemisphere and air temperature of Ruoqiang,Qiemo and Hetian stations during 1951-2005,the climatic variation of summer high temperature years in Southern Xinjiang and its climatic background were analyzed.Results show that the emergence of summer high temperature in this region is closely connected with the abnormal variations of atmospheric circulation over the North Hemisphere and sea temperature of North Pacific.It is also showed that the character indices of the subtropical high over the Northern Hemisphere in the preceding October and February have indication for summer temperature in the region.Namely,since January of each high-summer-temperature year of Southern Xinjiang,the departure distribution of sea temperature which is high in the southwest sea area and low in the northeast has appeared in North Pacific,and often lasted until May.However,sea temperature variations of the two sea areas were different,in January and February,the variation is smaller in southwest sea area while bigger in the northeast,on the contrary,it's bigger in the southwest and smaller in the northeast from March to May.