The low frequency oscillations of the sea surface temperature in the Equatorial Eastern Pacific and El Nino formation

In this paper the variations of the sea surface temperature anomalies (SSTA) in the Equatorial Eastern Pacific are analysed.The results show that there are two peaks in the spectrum.One is the low frequency oscillation with a period of 3-5 years, and the other is the quasi-biennial oscillation.The former shows a westward migration in the warm episode of SSTA and the latter has the opposite trend.The El Nino events will be formed while the two frquency bands are in phase in the warming stage of SSTA in the Equatorial Eastern Pacific.