SSTA年代际变化对ENSO事件的调制作用以及它与LOD、SOI等的关系研究  

Modulation of the SSTA Decadal Variation on ENSO Events and Relationships of SSTA With LOD,SOI,etc

作　　者：廖德春[1] 周永宏[1] 廖新浩[1] 

机构地区：[1]中国科学院上海天文台,上海200030

出　　处：《天文学报》2007年第1期36-47,共12页Acta Astronomica Sinica

基　　金：国家自然科学基金(10633030;10673025;10373017)资助项目

摘　　要：用带通滤波方法从日长变化(LOD)、南方涛动指数(SOI)和Nino各海区海面温度异常变化(SSTA)等资料中提取年际和年代际变化分量,研究了Nino3．4海区SSTA的年代际分量对ENSO事件的调制作用．研究发现,除了年际分量之外, SSTA的年代际分量对ENSO事件的表征和监测有重要影响．当ENSO事件比较强时,SSTA年代际变化分量的作用倾向于使ENSO事件的时间延长,并使事件的极端温度增大;当ENSO事件比较弱时,在SSTA年际变化中没有检测到的事件,可借助于年代际变化分量的调制作用得到检测．还研究了SSTA年际和年代际变化与SOI、热带太平洋海平面气压异常(SLPA)和信风异常(TWA),以及大气角动量(AAM)和海洋角动量(OAM)轴向分量(χ3)的相应变化之间的频谱相干性．结果表明在年际尺度上,SSTA与LOD、SOI、SLPA、TWA、大气角动量的轴向分量(χω3,χpib3和χωpib3)和海洋角动量的轴向分量(χv3和χv+bp3)等都有密切关系,其中以SOI、SLPA、TWA和χω3与SSTA的关系更加显著;在年代际时间尺度上,SSTA与SOI、SLPA、TWA、χω3以及χω+v3的关系更为密切,与LOD、大气压(χpib3)和洋底压强(χbp3)的关系较弱．Interannual and decadal components of the length of day （LOD）, Southern Oscillation Index （SOI） and Sea Surface Temperature anomaly （SSTA） in Nino regions are extracted by band-pass filtering, and used for research of the modulation of the SSTA on the ENSO events. Results show that besides the interannual components, the decadal components in SSTA have strong impacts on monitoring and representing of the ENSO events. When the ENSO events are strong, the modulation of the decadal components of the SSTA tends to prolong the life-time of the events and enlarge the extreme anomalies of the SST, while the ENSO events, which are so weak that they can not be detected by the interannual components of the SSTA, can also be detected with the help of the modulation of the SSTA decadal components. The study further draws attention to the relationships of the SSTA interannual and decadal components with those of LOD, SOI, both of the sea level pressure anomalies （SLPA） and the trade wind anomalies （TWA） in tropic Pacific, and also with those of the axial components of the atmospheric angular momentum （AAM） and oceanic angular momentum （OAM）. Results of the squared coherence and coherent phases among them reveal close connections with the SSTA and almost all of the parameters mentioned above on the interannual time scales, while on the decadal time scale significant connections are among the SSTA and SOI, SLPA, TWA, Χ^w 3 and Χ^w＋v 3 as well, and slight weaker connections between the SSTA and LOD,Χ^pib 3 and Χ^bp 3.

关 键 词：ENSO事件 日长变化 海面温度异常 南方涛动指数 

分 类 号：P127[天文地球—天体测量]