热带及北太平洋海表温度与两类El Niño事件的关系
Relationships between two types El Niño events and sea surface temperature of tropical and North Pacific
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摘要: 副热带及热带海温异常变化对两类厄尔尼诺事件具有一定影响,定量分析热带及北太平洋关键海区海表温度对两类厄尔尼诺事件(尤其是中太平洋型厄尔尼诺事件)的不同贡献,对完善两类厄尔尼诺事件预报模型及极端气候预报具有重要意义。本次研究利用海表温度资料,采用旋转经验正交函数分解、功率谱分析、相关分析等方法研究了热带及北太平洋区域海表温度异常变化关键区与两类厄尔尼诺事件的关系。结果表明:1985~2009年热带太平洋海表温度前两个模态的时空分布能够很好地表征两类厄尔尼诺事件发生过程中最大海温变化的时间演变特征。热带及北太平洋海表温度变化最显著的区域主要有四个,分别是赤道中东太平洋、加利福尼亚西南、阿留申群岛和白令海一带。其中阿留申群岛地区与其他海区存在显著的负相关。春季和秋季海温异常变化区域位于赤道中太平洋,夏季和冬季海温异常变化区域位于赤道东太平洋。根据热带及北太平洋海表温度显著变化关键区域与两类厄尔尼诺事件的密切关系,通过回归分析,建立了二者之间的回归方程,得到的结果为进一步研究热带及北太平洋关键海区海温对两类厄尔尼诺事件的影响提供有益的参考。Abstract: Sea surface temperature (SST) in tropical and North Pacific both have significant impact on El Niño events.The influencing degree of tropical and North Pacific was quantitatively analyzed by empirical orthogonal function、power spectral analysis and correlation analysis methods.The results show that the temporal and spatial distribution of the first and second empirical orthogonal function modes of the sea surface temperature anomalies capture the maximum positive warming features during the eastern Pacific El Niño and central Pacific El Niño events, respectively.The most significant anomalies of sea surface temperature anomalies in tropical and North Pacific are in four areas which locate in central and eastern tropical Pacific、the southwestern California、the Aleutian Islands and the Bering Sea.There is a significant negative correlation of SST between the Aleutian Islands and other three key areas.Central tropical Pacific is the key changing area of sea surface temperature in spring and autumn, while eastern tropical Pacific is the one in summer and winter.Based on the close relationship between sea surface temperature of four key areas and two types El Niños, the regression equations are obtained to describe the contributions of key areas during two types El Niño events, providing a reference for the studies of relationships between tropical and subtropical Pacific key areas and two types El Niño events.