SVD分析揭示的澳大利亚高压年际变化对中国夏季气温的可能影响  

Impacts of Interannual Variations of Australian High on the Summer Temperature in China by SVD Analysis

作　　者：张蓬勃[1,2,3] 管兆勇[1,2] 蔡佳熙[1,2] 

机构地区：[1]南京信息工程大学大气科学学院,江苏南京210044 [2]南京信息工程大学气象灾害省部共建教育部重点实验室,江苏南京210044 [3]南京市气象局,江苏南京210008

出　　处：《大气科学学报》2010年第1期58-66,共9页Transactions of Atmospheric Sciences

基　　金：国家科技支撑计划项目(2007BAC29B02);江苏省气象灾害重点实验室项目(KLME060101)

摘　　要：利用澳大利亚海平面气压和中国夏季气温站点资料,使用SVD和线性回归方法揭示了澳大利亚高压(以下简称澳高)的年际变化与中国夏季气温异常的联系。结果表明,SVD的第一模态(简称SVD1)时间系数与通常使用澳高指数相关可达到0.97。SVD1表示出澳大利亚高压的年际变化与中国江南地区夏季气温存在密切联系。澳高增强(减弱)时,江南地区夏季气温偏低(偏高)。整层垂直积分大气加热场、海平面气压场、500hPa的高度场变化以及降水和总云量的变化都对夏季气温的形成有一定作用。澳高对中国夏季气温的可能影响途径为:澳高强(弱)年时,澳大利亚地区低层的异常辐散风场在菲律宾东侧的暖池附近产生辐合(辐散),引起正(负)涡度源,激发P-J型波列,伴随着在南海—西太平洋地区产生副高正异常(负异常),导致副高偏西(偏东),进而增强(减弱)来自孟加拉湾的水汽输送,同时江南地区水汽和异常风场辐合(辐散),有利于(不利于)该地区降水异常的发生和维持,有益于气温降低(升高)。By using the sea level pressure data from NCEP-NCAR reanalysis and monthly mean temperature data from 107 stations in China,the relationships between interannual variations of the Australian high and summer temperature in China have been studied using the SVD singular value decomposition and regression methods. The time series of coefficient of left singular vector of SVD1 was found to be highly correlated with the Australian high index as reported in many studies. The correlation coefficient is 0. 97, which shows that the SVD1 can well depict the variations of the Australian high. The first mode of SVD displays a close relationship between interannual variations of the Australian high and the summer temperature in southern area of the Yangtze River. When the Australian high is stronger （weaker） than normal, summer temperature in southern area of the Yangtze River is significantly lower （higher）than normal. The changes of the vertically integrated diabatic heating, sea level pressure, and the geopo- tential height at 500 hPa, the variations of the precipitation and the total cloud cover are factors related to the formation of the temperature anomalies during boreal summer. When the Australian high is stron- ger（weaker） than normal,anomalous divergence（convergence） in Australia causes anomalous convergence （divergence） in the warm pool east of the Philippines and thus the anomalous positive （negative） eddy source, which excites the P-J wave pattern. Meanwhile, the western Pacific subtropical high seems to extend further westward （eastward） than normal, which transports more （less） water vapor northeastward to the southern area of the Yangtze River. At the same time, the anomalous convergence（divergence） of wind field and moisture over the southern area of the Yangtze River eventually facilitates more（less） rainfall in southern China during boreal summer and the lower（higher） temperature than normal in summer season.

关 键 词：澳大利亚高压 年际变化 中国夏季气温 

分 类 号：P461[天文地球—大气科学及气象学]