Asymptotic solution of a sea--air oscillator for ENSO mechanism

The EI Ni~{n}o/La Ni~{n}a--Southern Oscillation (ENSO) is aninterannual phenomenon involved in the tropical Pacificocean--atmosphere interactions. In this paper, a class of coupledsystem of the ENSO mechanism is considered. Based on a class ofoscillator of ENSO model, the asymptotic solution of a correspondingproblem is studied by employing the approximate method. It is provedfrom the results that the perturbation method can be used foranalysing the sea surface temperature anomaly in the equatorialeastern Pacific and the thermocline depth anomaly of theatmosphere--ocean oscillation for the ENSO model.