Stochastic theories for the irregularity of ENSO.

Stochastic Scenario for ENSO Irregularity

Lecture 3 ENSO’s irregularity and phase locking

That El Nino is aperiodic is seen, for example, in a nino3 time series (Fig. 26). The ENSO delayed oscillator mechanism may result in either self-sustained oscillations, or in a steady state solution that has a damped oscillatory mode. In the later case, oscillations may be excited by external stochastic (weather) noise. In the scenario in which ENSO is self-sustained, it may be irregular due t...

A Nonlinear Theory for El Niño Bursting

A new mechanism is proposed that explains two key features of the observed El Niño–Southern Oscillation (ENSO) phenomenon—its irregularity and decadal amplitude changes. Using a low-order ENSO model, the authors show that the nonlinearities in the tropical heat budget can lead to bursting behavior characterized by decadal occurrences of strong El Niño events. La Niña events are not affected, a ...

Predictability of El Niño as a Nonlinear Stochastic Limit Cycle

The El Niño phenomenon, synonymously El Niño-Southern Oscillation (ENSO), is an anomalous climatic oscillation in the Equatorial Pacific that occurs once every 3-8 years. It affects the earth’s climate on a global scale. Whether it is a cyclic or a sporadic event, or whether its apparently random behaviour can be explained by stochastic dynamics have remained matters of debate. Herein ENSO is v...

Hybrid coupled models of the tropical Pacific: I interannual variability

Two hybrid coupled models (HCMs), an intermediate complexity dynamical ocean model coupled to either a nonlinear neural network atmosphere (NHCM) or a linear regression atmosphere (LHCM), have been developed for the tropical Pacific. The ENSO (El Niño-Southern Oscillation) characteristics of the two coupled models were investigated. The results show that the NHCM can produce more realistic ENSO...