中文摘要：

利用近50年月平均的SODA海洋同化资料和NCEP大气再分析资料,研究了热带太平洋次表层海温异常（SOTA）年代际变率主要分布型以及与之相关的亚洲-北太平洋-北美地区上空异常大气环流场,并揭示了类ENSO模态与中国气候异常之间的联系。得到主要结果：（1）热带太平洋SOTA年代际变率有两种类ENSO模态。第一模为类ENSO事件成熟期热带太平洋年代际SOTA状态;第二模为类ENSO过渡期热带太平洋年代际SOTA状态。二者组合构成类ENSO事件40年左右及其背景下13年左右的周期振荡。（2）类ENSO事件对亚洲-北太平洋-北美上空中高纬和副热带大气系统年代际变化具有重要影响。类El Ni o成熟期间冬季,中高纬地区大气环流经向型发展,贝加尔湖高压脊加强,西太平洋副高偏强、位置偏西,蒙古高原为较强的异常反气旋环流。类El Ni o衰退期（类La Ni a发展期）夏季,贝加尔湖低压槽加深,乌拉尔山高压脊加强,西太平洋副高偏弱,新疆-河套地区为较强的异常反气旋环流距平。类La Ni a事件时相反。（3）热带太平洋类ENSO事件通过影响中高纬和副热带大气系统,造成中国北部地区上空南风距平的年代际变化,进而导致东亚季风和中国气候异常。类El Ni o事件成熟期,中国北部地区上空多异常偏北风,东亚季风弱,华北少雨,长江中、下游多雨;类El Ni o衰退（类La Ni a发展）期,中国北部地区上空亦为异常偏北气流,东亚季风较弱,华北少雨。中国气候异常型主要取决于类ENSO第一模态,而第二模态主要视位相异同来加强或减弱第一模态。两个类ENSO模态的共同作用导致1978年前后中国气候跃变和华北地区持续20余年的干旱。近期类ENSO模的振荡从1998年左右开始转为类La Ni a模态,大致在2018年左右结束。在此期间,华北降水有望增加,长江中、下游降水可能减少。

英文摘要：

In the present study,we investigate the decadal variability of the tropical Pacific subsurface ocean temperature anomaly（SOTA） and associated anomalous atmospheric circulation over Asia-North Pacific-North America,through analyzing 50 years of atmosphere-ocean data from the U.S.National Center for Environmental Prediction（NCEP） reanalysis project and Simple Ocean Data Assimilation（SODA）.Relationship between ENSO-like modes and climate of China is also revealed.Main results are as follows： （1） Decadal variability of tropical Pacific SOTA has two dominant ENSO-like modes.The primary mode is El Ni？o-like or La Ni？a-like mature phase pattern,and the second mode is associated with the El Ni？o-like/La Ni？a-like developing（La Ni？a-like/El Ni？o-like decaying） phase.These two modes form the cycle of ENSO-like events,which has a background fluctuation of about 40 year＇s period,superimposed with an oscillation of 13-year＇s period.（2） The ENSO-like event has significant influence on the decadal variations of Asian-North Pacific-North American and subtropical atmospheric circulation.During the mature phase of El Ni？o-like events,usually in winter,the atmospheric circulation with meridonal pattern in the mid-high latitude develops,a ridge of high pressure over Lake Baikal and a ridge of North American high intensifies,the west Pacific subtropical high strengthens and extends westward,and a strong anomalous anticyclone exists over the Mongolian plateau.When the El Ni？o-like event decays（La Ni？a-like develops）,usually in summer,the troughs over the Lake Baikal grow deep,while the west Pacific subtropical high weakens,and an anomalous anticyclone controls the Xinjiang-Hetao region.The case during the La Ni？a-like event is generally opposite.（3） The ENSO-like events in the tropical Pacific Ocean influence the atmosphere system of the mid-high latitude and subtropical regions,resulting in decadal variability of south wind over the northern China,and hence the East Asian mons