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 strength ening 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.