东亚太平洋与欧亚遥相关型的相互配置及其气候影响

The configuration between the East Asia Pacific and the Eurasian teleconnection patterns and its influence on the summer climate of China

利用近60 a中国160站夏季降水资料和NCEP/NCAR月平均位势高度场、风场等再分析资料,采用相关分析和合成分析等方法对东亚太平洋遥相关型(EAP)和欧亚遥相关型(EU)的不同配置特征及其对中国夏季降水的影响进行了研究。研究结果表明:EAP与EU两种遥相关型是相互独立的,相关系数为-0.03。两者存在以下四种配置:EAP和EU均活跃且位相相同(第I类配置)、EAP和EU均活跃且位相相反(第II类配置)、仅EU活跃(第III类配置)和仅EAP活跃(第IV类配置)。EAP与EU呈现不同配置类型时,中国夏季的降水分布相应的存在差异。当二者之间是第I类配置时,降水异常分布呈北方型;当二者配置为第II类时,降水异常分布呈现出中间型,雨带集中在长江流域;第Ⅲ类配置时,降水大值区主要集中在长江中上游黄河以南地区;而第Ⅳ类配置时,降水集中在长江中下游地区,雨带呈东北—西南走向。

Based on the monthly summer precipitation data of 160 stations in China and NCEP/ NCAR monthly reanalysis datasets, the summer precipitation distribution in China was examined using correlation and composite analysis. It was found that the East Asia Pacific Teleconnection pattern （EAP） and Eurasian Teleconnection pattern （EU） are independent of each other with a correlation coefficient of -0.03. There are four configurations between EAP and EU： （ Ⅰ ） both are significant and in phase; （ Ⅱ） both are significant but out-of-phase ; （ Ⅲ） EU is dominated and （ Ⅳ ） EAP is dominated. The rainfall distribution becomes different with the configuration. When configuration Ⅰ exists, the area of a- nomalies of summer rainfall is in the North of China. When the configuration belongs to Ⅱ , the rainfall anomalies show medium, which means the rainfall will be unusually greater in the Yangtze River. Whenthe EU is dominated, i.e. configuration Ⅲ exists, most of the rainfall appears in the upper and middle reaches of the Yangtze River as well as the southern region of the Yellow River. However, during config- uration Ⅳ, i.e. the EAP is dominated, the middle and lower reaches of the Yangtze River become the rainfall anomaly areas. The rain belt presents northeast- southwest direction.