不同强度El Nio的衰减过程.Ⅰ,强El Nio的衰减过程

• 作 者: 刘长征 薛峰
• 机 构: 中国科学院大气物理研究所,国家气候中心,
• 出 处: 地球物理学报
• 发表日期: 2010年01期
• 关键词: 衰减过程 El Ni ENSO 赤道东太平洋 平常态 La Nia 西太平洋 南方涛动 海气相互作用 温跃层

将1951～2004年期间的12次El Nio事件分为强、中等、较弱和弱4类,结果发现,强和较弱El Nio衰减进入La Nia,但是中等和弱El Nio衰减进入平常态.因此,El Nio的衰减结果与自身强度之间存在密切的非线性关系.进一步的研究表明,负异常信号自西太平洋向中东太平洋的东传主导了强El Nio事件向La Nia的转变过程,其具体动力过程类似于西太平洋振子理论.热带西北太平洋(WNP)大气异常反气旋在强El Nio位相转变中起核心作用,它的维持和缓慢东移是赤道东风异常维持和发展的原因,而后者通过激发Kelvin波导致了ENSO从El Nio向 La Nia的转变.

The 12 El Nio events from 1951 to 2004 were divided into four categories: strong, moderate, weak and weak. It was found that strong and weak El Nio attenuated into La Nia, but medium and weak El Ni  衰 decays into the normal state, so there is a close nonlinear relationship between the decay result of El Ni  o and its own strength.Further studies show that the negative anomaly signals are dominated by the east-west transmission from the western Pacific to the Middle East Pacific The specific dynamical process of the Nio event to La Nia is similar to that of the Western Pacific oscillator theory. The anomalous anticyclone of the WNP plays a central role in the phase transition of strong El Nio, And the slow eastward migration are the reasons for the anomalous maintenance and development of the equatorial easterly anomaly, while the latter caused the ENSO transition from El Nio to La Nia by exciting Kelvin waves.