2015/2016年超强El Nio局地海气特征及其特殊性  

Characteristics and particularity of local air-sea processes for the 2015/2016 super El Nio event

作　　者：张文君[1] 耿新[1] 

机构地区：[1]南京信息工程大学气象灾害教育部重点实验室/气候与环境变化国际合作联合实验室/气象灾害预报预警与评估协同创新中心,江苏南京210044

出　　处：《大气科学学报》2016年第6期778-787,共10页Transactions of Atmospheric Sciences

基　　金：国家自然科学基金资助项目(41675073);国家公益性行业(气象)专项(GYHY20150613;GYHY20140622);江苏省高校自然科学研究资助项目(13KJB170013);江苏省青蓝工程和六大人才高峰项目

摘　　要：利用NOAA海表温度和NCEP/NCAR大气环流等全球再分析资料,讨论了2015/2016年超强El Nio事件局地海气过程的演变特征,并与1982/1983和1997/1998年两次强El Nio事件做了对比分析。结果表明,2015/2016年El Nio在峰值强度、持续时间、累计海温距平等指标上都略强于前两次El Nio,可视为有完整气象观测纪录以来的最强事件;与前两次事件相比,2015/2016年El Nio海温异常中心位置明显偏西,热带东太平洋海温相对较冷而中太平洋更暖,由于热带对流对海温的非线性响应,赤道东太平洋降水相对较弱,中太平洋则显著偏多,这在El Nio当年12月至次年4月尤为明显;此外,在前两次El Nio的成熟期至衰减期,中太平洋大气响应都存在明显的南移特征,西风异常和对流中心都从赤道南移到了5°S以南。而2015/2016年中太平洋大气响应一直位于赤道附近,南移特征相对较弱,ENSO和年循环相互作用的组合模态相比前两次较弱,西北太平洋反气旋的强度也弱于前两次。这主要是由于2015年冬季至2016年春季,热带太平洋暖海温异常位置偏西,中太平洋海温异常明显强于前两次,叠加气候平均态海温之后,赤道南北两侧海温都高于对流阈值,对流旺盛,这大大削弱了大气响应的经向移动和ENSO组合模态的强度。Based on the latest monthly global reanalyzed NOAA（ National Oceanic and Atmospheric Administration）sea surface temperature（ SST） and NCEP（ National Centers for Environmental Prediction）/ NCAR（ National Center for Atmospheric Research） atmospheric circulation data,we analyzed the characteristics of the local air-sea processes for the 2015/2016 super El Nino event,and the differences with previous（ 1982/1983 and 1997/1998）super El Nino events are also discussed. The 2015/2016 super El Nino event can be regarded as the strongest on record,since the corresponding indices of El Nino duration,peak intensity and accumulated SST anomaly remain the strongest among the existing three super El Nino events. The location of the tropical SST anomaly was displaced further west compared with the 1982/1983 and 1997/1998 events. As a result,the SST of the 2015/2016 El Nino event was colder in the tropical eastern Pacific and warmer in the central Pacific than that of the previous two super El Nino events. Due to nonlinear responses of the convectional precipitation to the SST anomaly,precipitation anomalies were weaker in the tropical eastern Pacific and much stronger in the central Pacific during the 2015/2016 El Nino event than those during the previous two super El Nino events,which was particularly evident from the El Nino December to the following April. Moreover,the 1982/1983 and 1997/1998 super El Nino events exhibited obvious southward shifts of the atmospheric responses from the equator to 5°S in the tropical central Pacific during the mature-to-decay phase. However,the precipitation and the westerly wind anomalies during the same phase of the 2015/2016 event were mainly located near the equator and the meridional movements were not as robust as those during the1982/1983 and 1997/1998 events. The intensities of the ENSO combination mode,which results from the interaction between ENSO and the annual cycle,were also weaker during the 2015/2016 event than those during the previous two super El Nino eve

关 键 词：2015/2016年超强El Nino ENSO组合模态 大气响应南移 西北太平洋反气旋 

分 类 号：P732[天文地球—海洋科学]