混合海气耦合模式中的ENSO循环及其形成机制

在无异常外强迫的情况下, 将混合海气耦合模式进行了45年的模拟积分.结果表明:模式能较好地再现类似ENSO循环的热带太平洋海洋、大气的年际振荡, 模式ENSO循环的主周期为4~5年; 探讨了ENSO循环的负反馈机制, 指出:暖态的消亡与El Ni?o发展过程中太平洋东部不断增强的东风异常所产生的冷水上翻的加强以及纬向向西的冷平流有关; 冷态的消亡主要由赤道波的时滞效应所致.

ENSO Simulated by a Hybrid Coupled Ocean-atmosphere Model and Its Mechanisms

A hybrid coupled ocean atmosphere model is developed, with which a 45 year simulation is performed. Analysis shows that the model can reproduce ENSO interannual variability over the tropical Pacific. The principal period is about 4 to 5 years. The negative feedback mechanism of ENSO is investigated. The results show that the damping of warm phase can be attributed to the strengthening of the cold water upwelling accompanied with the strong anomalous easterly over the eastern Pacific during the developing period of El Nino and the cold advection along the equator. The damping of cold phase is mainly related to the delaying effects of the equatorial wave reflection.WT5BZ] WT5HZ]