ENSO发展和衰亡阶段中非线性项的作用

发布时间：2018-05-09 08:14

本文选题：ENSO + 非线性项　；参考：《气象学报》2017年05期

【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。
[Abstract]:Based on HadISST) and simple Ocean Data assimilation (SODA 2.2.4) data set, the skewness characteristics of sea surface temperature anomalies in the equatorial Pacific from 1979 to 2015 were analyzed. By diagnosing the mixed layer heat balance equation, the different roles of nonlinear terms in the development and decay of different types of ENSO are discussed. The results show that the bias of the central El Ni 帽 o and La Ni 帽 a events is very weak, and the symbol is opposite, and the intensity is equal, while the eastern type El Ni 帽 o has a very strong positive bias. That is, the intensity asymmetry of ENSO is mainly from the contribution of eastern El Nino, and the sea surface temperature anomalies of central El Ni 帽 o and La Nina show quasi-symmetric characteristics. In the development stage of ENSO event, the nonlinear term has a strong positive contribution to both the eastern El Nino and La Nina, while the positive contribution to the central El Ni 帽 o is relatively weak. This will promote the enhancement of the intensity of the eastern El Ni 帽 o and inhibit the development of the La Nina amplitude, which is beneficial to the generation of the asymmetry of the intensity of the ENSO. During the decaying phase of the ENSO event, the nonlinear term maintains a positive contribution to La Nina, but the intensity decreases greatly. The attenuation of eastern El Nino and central El Nino is promoted and inhibited respectively, which may be one of the important reasons for the fast attenuation of eastern El Nino and the slow attenuation of central El Nino.
【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;
【基金】：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)
【分类号】：P732

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