Long-Term Forecasting of the Extreme El-Niño Events

Abstract

Until now the widley used predictive long-term hazard models of the most intense natural phenomena do not yield predictions other than the mean return period, which indicates only a mean recurrence time, but does not allow any time prediction of the of occurrence of the phenomena. To achieve more certain estimates an alternative model is proposed, and applied for the prediction of the most violent El-Ninos events. The model is based on the observations which show that (i) the oceanic thermal reservoir generating the El-Ninos events continuously accumulate thermal energy, but releases it both through small and intense El-Ninos events, and that (ii) such an oceanic system evolves saving an almost constant average power. This means that the higher (the less) the number of small events releasing energy after the occurrence of an intense one, the later (the earlier) an intense event is expected to occur. The years of occurrence of all the very strong events estimated by the model are found to be in fair agreement with the observations.