| 1月份两类ENSO的海气环流模态分析 |
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| 引用本文： | 张东凌,卢姁,张铭.1月份两类ENSO的海气环流模态分析[J].大气科学,2019,43(4):741-758. |
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| 作者姓名： | 张东凌 卢姁 张铭 |
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| 作者单位： | 中国科学院大气物理研究所,北京,100029;解放军32021部队,北京100094;国防科技大学气象海洋学院大气环流与短期气候预测实验室,南京211101;国防科技大学气象海洋学院大气环流与短期气候预测实验室,南京,211101 |
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| 基金项目： | 国家重点研发计划项目2016YFB0200800 |
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| 摘 要： | 本文对1950～2001年1月份的大气风场和大洋流场做了联合复EOF（Empirical Orthogonal Function）分解,用以探讨1月份两类ENSO（El Ni?o-Southern Oscillation）的海气环流及耦合情况,所得结果主要有:该分解第1、2模态空间场分别相应于东部型、中部型ENSO,前者在赤道太平洋东部和中部都有海温动力异常,并以东部异常最强,后者仅在中部存在此异常,两模态的时间系数都与ENSO有很好相关,为此第1、2模态可分别称为东部型、中部型ENSO的风场流场（异常）模态。东部型ENSO模态具有3～6年的年际变化和13～14年的年代际变化,中部型则有明显的7年年际变化和12、17年的年代际变化,两者中约13年的周期与冬季北太平洋NPGO（North Pacific Gyre Oscillation）的周期相同。东、中部型El Ni?o期间,沃克环流上升支分别从印尼东移至赤道西、中太平洋,并有所减弱;南、北支哈得莱环流则分别位于日界线以东及该线附近,且均有所加强,从而使南、北太平洋副热带高压偏强;而在5°S的南美沿岸则分别有垂直运动上升和下沉异常。在海气耦合上,两类ENSO模态在赤道中太平洋均存在西风异常与海洋赤道Kelvin波和Rossby波的波包解耦合,而海温动力异常对大气的影响则都起到负反馈作用,从而有利于ENSO的维持和稳定。
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| 关 键 词： | 东部型ENSO 中部型ENSO 海气环流 复EOF分解 |
| 收稿时间： | 2017/9/5 0:00:00 |
Analysis of Ocean-Atmosphere Circulation Modes Associated withTwo Types of ENSO in January |
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| ZHANG Dongling,LU Xu,and ZHANG Ming.Analysis of Ocean-Atmosphere Circulation Modes Associated withTwo Types of ENSO in January[J].Chinese Journal of Atmospheric Sciences,2019,43(4):741-758. |
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| Authors: | ZHANG Dongling LU Xu and ZHANG Ming |
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| Institution: | 1.Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 1000292.Unit 32021, PLA, Beijing 100094;Laboratory of Atmospheric Circulation and Short-Range Climate Forecast, College of Meteorology and Oceanography, National University of Defense Technology, Nanjing 2111013.Laboratory of Atmospheric Circulation and Short-Range Climate Forecast, College of Meteorology and Oceanography, National University of Defense Technology, Nanjing 211101 |
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| Abstract: | In this paper, combined complex Empirical Orthogonal Function（CEOF）analysis is applied to the atmospheric wind and ocean flow fields in January from 1950 to 2001 to understand the coupled ocean-atmosphere circulation associated with two types of El Ni?o-Southern Oscillation（ENSO）in January. The results are as follows. The first and second modes respectively correspond to the Eastern Pacific type of ENSO (EP-ENSO) and the Central Pacific type of ENSO (CP-ENSO). The former type of ENSO corresponds to sea surface temperature (SST) anomalies in the eastern and central equatorial Pacific, and the eastern anomaly is stronger; the latter corresponds to SST anomaly only in the central equatorial Pacific. Their time coefficients are closely related to ENSO. Thereby, they can be named as EP-ENSO mode and CP-ENSO mode regarding wind-current fields, respectively. The EP-ENSO mode has distinct interannual and interdecadal variations with periods of 3 to 6 and 13 to 14 years. The CP-ENSO mode has distinct interannual and interdecadal variations with periods of 7, 12 and 17 years. The 13-year period is similar to the NPGO（North Pacific Gyre Oscillation）period of winter climate mode in the North Pacific. During the Eastern and Central Pacific type of El Ni?o, the ascending branch of the Walker Circulation shifts eastward from Indonesia to the western or central equatorial Pacific, and the intensity weakens; the southern and northern branches of Hadley Circulation are respectively located to the east of and near the international date line, and the intensity enhances, which causes the subtropical high to become stronger; along the coast of South America near 5°S, there are anomalies of updraft and downdraft. For the two types of ENSO modes, westerly anomalies and wave packet solutions of Kelvin wave and Rossby wave are coupled near the central equatorial Pacific. Sea temperature kinetic anomaly has a negative feedback on the atmospheric circulation, which is favorable for the maintenance and stability of ENSO. |
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| Keywords: | Eastern Pacific type of ENSO (EP-ENSO) Central Pacific type of ENSO (CP-ENSO) Ocean-atmosphere circulation Complex empirical orthogonal function |
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