Behaviour of Coupled Modes in a Simple Nonlinear Air-Sea Interaction Model

In this article, a model with the simplest framework is constructed and solved analytically. It is shown that intrasensonal wave coexists with interannual variation, and ENSO cycle arises from coupled Kelvin wave destabilisation. Its irregularity can be related to reasonable model parameters. External processes have some impor?tant effects on nonlinear air-sea interaction modes.