| ENSO发展和衰亡阶段中非线性项的作用 |
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| 引用本文： | 袁心仪,张文君,耿新.ENSO发展和衰亡阶段中非线性项的作用[J].气象学报,2017,75(5):784-796. |
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| 作者姓名： | 袁心仪 张文君 耿新 |
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| 作者单位： | 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, 南京, 210044 |
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| 基金项目： | 国家自然科学基金项目（41675073）、国家公益性行业专项（GYHY20150613）、江苏省高校自然科学研究项目（13KJB170013）、江苏省青蓝工程、六大人才高峰及高校优势学科建设工程（PAPD）。 |
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| 摘 要： | 利用哈得来中心海表温度（HadISST）和美国马里兰大学海洋同化（Simple Ocean Data Assimilation，SODA 2.2.4）数据集，分析了1979-2015年赤道太平洋地区海表温度异常的偏度特征；并通过诊断混合层热量收支平衡方程着重探讨了非线性项在不同类型ENSO发展衰亡过程中起的不同作用。研究结果表明，中部型厄尔尼诺和拉尼娜事件的偏度很弱，且符号相反、强度相当，而东部型厄尔尼诺的偏度为很强的正值，即ENSO的强度非对称性主要来自东部型厄尔尼诺的贡献，中部型厄尔尼诺和拉尼娜的海表温度异常呈现准对称特征。在ENSO事件的发展阶段，非线性项对东部型厄尔尼诺和拉尼娜均有很强的正贡献，而对中部型厄尔尼诺的正贡献相对较弱，这会促进东部型厄尔尼诺强度的增强而抑制拉尼娜振幅的发展，从而有利于ENSO强度非对称性的产生；在ENSO事件的衰亡阶段，非线性项对拉尼娜维持正贡献但强度大为减弱，对东部型厄尔尼诺和中部型厄尔尼诺的衰减则分别起促进和抑制作用，这可能是东部型厄尔尼诺衰减速度较快而中部型厄尔尼诺衰减速度较慢的重要原因之一。
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| 关 键 词： | ENSO 非线性项 非对称性 |
| 收稿时间： | 2016/12/23 0:00:00 |
| 修稿时间： | 2017/5/8 0:00:00 |
Effects of nonlinear terms during ENSO developing and decaying phases |
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| YUAN Xinyi,ZHANG Wenjun and GENG Xin.Effects of nonlinear terms during ENSO developing and decaying phases[J].Acta Meteorologica Sinica,2017,75(5):784-796. |
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| Authors: | YUAN Xinyi ZHANG Wenjun and GENG Xin |
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| Institution: | Key Laboratory of Meteorological Disaster, Ministry of Education/International Joint Laboratory on Climate and Environment Change/Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters, Nanjing University of Information Science and Technology, Nanjing 210044, China |
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| Abstract: | The features of sea surface temperature (SST) anomaly skewness in the equatorial Pacific are investigated based on the SST dataset from the Hadley Center and the Simple Ocean Data Assimilation (SODA 2.2.4) dataset from the University of Maryland. Impacts of nonlinear terms on the developing and decaying speeds of different types of ENSO events are further studied through analyzing the heat budget of mix-layer sea temperature. The results show that the asymmetry of ENSO amplitude is mainly attributed to the EP El Niño, and the SST anomaly amplitude associated with the CP El Niño displays a quasi-symmetric feature with that of La Niña. Nonlinear terms exhibit positive effects during the developing phases of EP El Niño and La Niña, which tend to strengthen the EP El Niño amplitude but suppress the La Niña amplitude. However, the influence of nonlinear terms on the CP El Niño is relatively smaller compared to that on other types of ENSO. The overall effects of the nonlinear terms largely lead to the formation of the ENSO amplitude asymmetry. During the ENSO decaying phases, nonlinear terms remain positive values during La Niña but with a much weaker intensity. In addition, nonlinear terms accelerate and decelerate the EP and CP El Niño''s decay, respectively. This may be responsible for the faster decaying speed during the EP El Niño events compared to that during the CP El Niño events. |
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| Keywords: | ENSO Nonlinear term Asymmetry |
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