东亚夏季降水与全球海温异常的年代际变化关系  

Interdecadal Relationship between the East Asian Summer Precipitation and Global Sea Surface Temperature Anomalies

作　　者：叶晓燕[1] 陈崇成[1] 罗明[1,2] 

机构地区：[1]福州大学地理空间信息技术国家地方联合工程研究中心空间数据挖掘与信息共享教育部重点实验室,福建福州350000 [2]香港中文大学环境能源及可持续发展研究所,香港999077

出　　处：《地球科学进展》2016年第9期984-994,共11页Advances in Earth Science

基　　金：国家自然科学基金青年科学基金项目"两类厄尔尼诺事件对东亚夏季风进退的影响研究"(编号:41401052)资助~~

摘　　要：利用1901—2010年GPCC逐月降水、Had ISST月平均海表温度、NOAA 20世纪再分析等资料,采用最大协方差分析(Maximum Covariance Analysis,MCA)、相关、回归等方法研究了东亚地区夏季降水与全球海表温度异常之间的年代际时空变化关系。MCA分析结果表明,东亚地区夏季降水与全球海温异常耦合关系在年代际尺度上主要表现为4个模态,分别受全球变暖、太平洋年代际涛动PDO、大西洋多年代际涛动AMO和北太平洋涡旋振荡NPGO影响,各自解释了27.7%,12.5%,8.9%和7.3%的方差。第一模态由于受全球变暖影响,东亚大部分地区水汽充足,因此东亚大部分地区降水均偏多。第二模态的降水异常表现为东亚中部地区降水偏多而南部和北部偏少的"南北旱中间涝"的三极型分布,其可能原因是太平洋年代际涛动使得东亚夏季风减弱,不利于水汽往北输送,引起水汽在东亚中部聚集,导致该地区降水偏多;同时西风带往南偏移,使得东亚中部地区对流增强,也引起该地区降水偏多。第三模态的降水异常则主要为"南涝北旱"的偶极分布型,可能原因是东亚大槽向东南方向偏移,东亚北部西风带减弱,使得东亚北部对流减弱、降水偏少,而东亚南部地区则对流增强、降水偏多。第四模态降水异常呈现出"南北涝中间旱"的三极型分布特征,其原因是东亚中部地区高层出现异常东风,对流活动减弱,导致东亚中部降水偏少,而南部和北部地区降水偏多。This study investigated the decadal relationship between the East Asian （EA） summer precipitation （EASP） and global sea surface temperature anomaly （SSTA） patterns. Maximum covariance analysis （MCA） was used to identify the coupling relationship between EASP and global SSTA. Four leading coupling modes were iden- tified by MCA and they explained 27.7% ,12.5% ,8.9% ,and 7.3% of the total variance, respectively. The spa- tial pattern of EASP of the first leading mode exhibited more-than-normal precipitation in most regions of EA. The second mode of EASP depicted a north-south ＂-＋-＂ tripole pattern. The third one showed a ＂wet south and dry north＂ pattern, and the fourth mode exhibited a north-south ＂＋-＋＂ tripole pattern. The four coupling modes were suggested to be modulated by the global warming, Pacific Decadal Oscillation （PDO）, Atlantic Multidecadal Oscil- lation （AMO）, and North Pacific Gyre Oscillation （ NPGO）, respectively. The atmospheric processes and mechanisms underlying such modulations were also investigated. In the first coupling mode, global warming was favorable for increasing water vapor and precipitation over most parts of EA. In the second mode, PDO weakened the EA summer monsoon circulation, and it decreased precipitation in northern and southern EA regions and increased precipitation in the central EA region. The third mode was affected by AMO, which displaced the EA trough southward and weakened the convective activity over the northern EA region, thus leading to deficient precipitation in northern EA region. In the fourth mode, the EA summer monsoon was strengthened by NPGO, thus increasing precipitation in the northern and southern regions and decreasing precipita- tion in the central region.

关 键 词：东亚夏季风 降水 海表温度异常 最大协方差分析 年代际变化 

分 类 号：P463.1[天文地球—大气科学及气象学]