长江流域夏季气温变化型及其成因Ⅱ：年代际变化  

A classification of the summertime temperature patterns in the middle and lower reaches of the Yangtze River and their causesⅡ:Interdecadal variations

作　　者：蔡佳熙[1] 管兆勇[1] 于田田[1] 卢楚翰[1] 

机构地区：[1]南京信息工程大学气象灾害省部共建教育部重点实验室,大气科学学院,南京210044

出　　处：《气象学报》2011年第1期112-124,共13页Acta Meteorologica Sinica

基　　金：国家科技支撑计划课题(2007BAC29B02);江苏省研究生培养创新工程(CX09B_220Z)

摘　　要：采用中国气象局整编的气温资料、ERA再分折资料、哈得来中心月平均海温资料,分析了长江流域夏季气温的变化型在年代际时间尺度上的形成机理。结果表明:长江中下游地区夏季气温呈现出全区一致、南北反相以及东西反相3种分布型;年代际尺度变化与年际尺度变化共有相同的空间型;特别有趣的是,长江流域夏季气温变化的第3模(EOF3)的时间系数与全球增暖趋势一致,其空问分布表现为长江下游越来越暖,而长江中上游越来越冷。在年代际尺度上,3种异常型分别对应不同特点的环流型,其中第2模对应的高度场在长江中下游地区上空是准正压结构;第1模的年代际变化与沿西风急流传播的波列状结构以及源自北大西洋的波列有关。第2模与沿西风急流传播的波列状结构以及自热带西太平洋出发的欧亚型(EAP)遥相关波列相联系,反映出中纬度和低纬度对长江中下游地区的共同作用。而第3模则与北极涛动存在一定联系,体现出中-高纬度的相互作用;长江中下游地区夏季气温异常分布与海温尤其是太平洋和印度洋海温存在联系,其中太平洋年代振荡对南北反相型气温分布起到一定作用,而西北太平洋在全球变暖背景下的异常冷海温对东西反相型气温分布产生影响。同时,印度洋海温异常亦与前两个模态的气温分布型存在联系。Using the temperature data of China Meteorological Administration,the ERA reanalysis data as well as Hadley monthly mean SST,we have analyzed the variations of summertime temperature in the middle and lower reaches of the Yangtze River and the associated mechanisms on interdecadal timescales.The summertime temperatures show three principal modes. The interannual and interdecadal variations share the same modes.The anomalous circulations related to both EOF1 and EOF3 show a baroclinic structure in vertical while EOF2 barotropic.It is interesting to notice that PC3 is consistent with the global warming trend;it is warming（cooling）in the lower（the upper and middle）reaches of the Yangtze River.On interdecadal timescale. the aforementioned three modes are related to the different circulation anomalies.The leading mode is found to be related with the wave trains propagating along the Asian jet as well as the wave trains originated from the North Atlantic.And the second mode is connected with the wave trains propagating along the Asian jet as well as the EAP（Eurasion Pattern）trains from the tropical western Pacific showing the co-effects from the middle latitudes and the low latitudes on the region we concern. Besides,the third one correlates with the AO（Arctic Oscillation）,implying the interaction between the high latitudes and the middle latitudes.Additionally,the SSTA in the Pacific Ocean as well as the Indian Ocean affects the spatial patterns of the temperature anomalies in the middle and lower reaches of the Yangtze River.The northern-southern seesaw mode of surface air temperature is related lo the PDO,while the eastern-western seesaw mode is related to the abnormal cold SSTA in the northwestern Pacific.The SSTA in the Indian Ocean may also affect the first two modes.

关 键 词：长江中下游 气温型 年代际变化 夏季 

分 类 号：P423[天文地球—大气科学及气象学] P434