El nino chaos: overlapping of resonances between the seasonal cycle and the pacific ocean-atmosphere oscillator

Science. 1994 Apr 1;264(5155):72-4. doi: 10.1126/science.264.5155.72.


The El Niño-Southern Oscillation (ENSO) cycle is modeled as a low-order chaotic process driven by the seasonal cycle. A simple model suggests that the equatorial Pacific ocean-atmosphere oscillator can go into nonlinear resonance with the seasonal cycle and that with strong enough coupling between the ocean and the atmosphere, the system may become chaotic as a result of irregular jumping of the ocean-atmosphere system among different nonlinear resonances. An analysis of a time series from an ENSO prediction model is consistent with the low-order chaos mechanism.