我国东部梅雨期降水的年际和年代际变化特征及其与大气环流和海温的关系  

Interannual and Interdecadal Variations of Precipitation over Eastern China during Meiyu Season and Their Relationships with the Atmospheric Circulation and SST

作　　者：马音[1,2] 陈文[1] 冯瑞权[3] 梁嘉静[3] 梁永权[3] 

机构地区：[1]中国科学院大气物理研究所季风系统研究中心,北京100190 [2]中国科学院研究生院,北京100049 [3]澳门地球物理暨气象局

出　　处：《大气科学》2012年第2期397-410,共14页Chinese Journal of Atmospheric Sciences

基　　金：国家重点基础研究发展计划项目2009CB421405;国家自然科学基金资助项目41025017;40921160379

摘　　要：基于我国160站59年(1951～2009年)的月降水观测资料、美国气象环境预报中心和国家大气研究中心(NCEP/NCAR)提供的再分析资料和Hadley中心的海表温度(Sea Surface Temperature,简称SST)资料,对我国东部(100°E以东,15°N～40°N)梅雨期(6月和7月)降水的时空变化特征进行了分析,结果发现:我国梅雨期降水主要表现为长江—华南反位相变化型和江南一致变化型两个模态。通过波谱分析的方法将梅雨期降水量变化中的年际(周期<8年的部分)和年代际(周期≥8年的部分)两种时间尺度进行分离,对这两种时间尺度上降水的时空变化规律分别进行分析,结果发现:无论是在年际还是年代际时间尺度上,我国东部梅雨期降水都主要表现为长江—华南反位相变化型和江南一致变化型,其中长江—华南反位相变化型有明显的年际和年代际变化,而江南一致变化型则主要表现为年代际变化。进一步对与这两种不同时间尺度相联系的大气环流和海温异常进行分析,结果发现:与长江—华南反位相变化型相联系的大气环流异常在年际时间尺度上表现为欧亚大陆中高纬的双阻型,从低纬到高纬"+-+"的经向波列分布,东亚副热带急流显著增强;在年代际时间尺度上表现为欧亚大陆一致的正位势高度异常,副热带高压增强北抬。海温异常在年际时间尺度上主要是前期日本附近海域和印度洋海区以及同期南海附近海域的正海温异常;在年代际时间尺度上主要是同期北太平洋中部"马蹄形"的负海温异常。与江南一致变化型相联系的大气环流异常在年际时间尺度上表现为欧亚大陆中高纬的东阻型,东亚沿岸从低纬到高纬"+-+"的经向波列分布;在年代际时间尺度上表现为大陆低压显著减弱,东亚副热带急流减弱南移。海温异常在年际时间尺度上主要是前期北太平洋的负海温异常和澳大利亚东部沿岸的正海温异常,�Based on the monthly mean rainfall data at 160 China stations, the National Centers for Environmental Prediction/National Centers for Atmospheric Research （NCEP/NCAR） reanalysis dataset, and HadISST1 dataset for 1951 - 2009, the temporal evolution and spatial distribution of precipitation over eastern China （15~N - 40~N, east of 100~E） during the Meiyu season （June and July） are investigated with the empirical orthogonal function （EOF）. It shows that there are two dominant modes, the first EOF mode depicting a precipitation oscillation be- tween the Yangtze River valley and South China, and the second EOF mode describing a consistent precipitation a- nomaly over the south of the Yangtze River. In this study two time scales are separated as： interannual component whose period is shorter than eight years and interdecadal component whose period is longer than eight years. After analyzing the precipitation at these two time scales during Meiyu season, it is found that for both of the annual scale and the decadal scale, the first two leading modes are a precipitation oscillation between the Yangtze River valley and South China, and a consistent precipitation anomaly over the south of the Yangtze River. The result of the compari- son between these two time scales shows that the pattern for the precipitation oscillation between the Yangtze River valley and South China has clear interannual and interdecadal variations, and the pattern for the consistent precipita- tion anomaly over the south of the Yangtze River is mainly characterized by interdeeadal variation. The atmospheric circulation and the sea surface temperature （SST） patterns associated with these two modes are investigated through the regression / correlation method. It shows that although the leading modes of interannual component are similar to those at the deeadal scale, the associated circulation and SST anomalies are quite different. The atmospheric cir- culation anomalies associated with the pattern which shows the precipitation osc

关 键 词：梅雨期降水 年际变化 年代际变化 大气环流异常 海温异常 

分 类 号：P461[天文地球—大气科学及气象学]