摘要
利用1979—2007年NOAA重建海温逐月资料和中国160站夏季降水资料,使用扩展奇异值分解(extended singular value decomposition,ESVD)方法,研究了冬季热带太平洋海温异常与次年夏季中国降水异常季节内演变型之间的关系,指出前冬El Nio事件是与次年夏季中国降水季节内变化相联系的最重要的热带太平洋海温异常模态。相应的降水异常季节内变化情况为:6月在长江以南为正异常,江淮流域有负异常;7月在华南沿海有负降水异常,而正异常北进到长江流域,华北地区也出现正降水异常;8月在长江南北分别为少雨和多雨。进一步研究前冬El Nio事件与次年春夏印度洋、太平洋海温异常、对流层低层风场异常以及副热带高压等的联系,结果表明:El Nio事件发生的次年春夏,热带西太平洋周边存在东负西正的海温异常分布;西太平洋反气旋异常较强;副高在6月、7月偏西偏北,但在8月迅速南退。虽然与El Nio事件相联系的6月与7月、8月的降水型不同,但是西太平洋反气旋异常带来的充沛水汽造成7月长江流域雨季多雨,8月副高迅速南退带来的又一次长江流域降水,造成了El Nio事件发生次年夏季长江流域涝而华南沿海旱的夏季平均降水异常型。
By using the National Oceanic and Atmospheric Administration extended reconstructed sea surface temperature（SST） V3 dataset and the summer rainfall of 160 stations in China from 1979 to 2007,the extended singular value decomposition（ESVD） is performed to explore the relationship between the winter SST anomaly in the tropical Pacific and the intraseasonal variation of China＇s rainfall in the following summer.The result of ESVD shows that El Nio event is the most dominant pattern of winter tropical Pacific SST anomaly coupling with the intraseasonal variations of following summer rainfall anomaly in China.And corresponding pattern of the rainfall anomaly in China are characterized by positive anomalies in the south of the Yangtze River and negative anomalies in the Yangtze-Huaihe River Valley in June,negative anomalies in South China and positive anomalies in the Yangtze River Valley and North China in July,and negative（positive） anomaly on the South（North） of Yangtze River in August.Furthermore,we studied the relationship between the El Nio events and the SST anomalies in the tropical Indian Ocean and Pacific,the wind anomalies of the lower troposphere,and the western Pacific subtropical high in the following spring and summer.It is pointed out that there are the ＂negative in East and positive in West＂ SST anomalies pattern around tropical western Pacific and significant northwestern Pacific anticyclone anomalies in spring and summer following El Nio events.The western Pacific subtropical high is more western and northern than the normal in June and July,and rapids retreat southward in August.Therefore,positive rainfall anomalies in the Yangtze River Valley are brought by the strong western Pacific anticyclone anomaly associated with abundant water vapor in July.In August there are also the positive rainfall anomalies in the Yangtze River Valley because of the rapid southwards retreatment of subtropical high.These two rainfall processes cause the summer mean rainfall anomalies patter
出处
《大气科学学报》
CSCD
北大核心
2010年第5期513-519,共7页
Transactions of Atmospheric Sciences
基金
国家自然科学基金重大项目(40890151)
国家重点基础研究发展计划项目(2009CB421405)
"十一五"国家科技支撑计划重点项目(2006BAC03B03)
