Prospects for predicting two flavors of El Niño

Abstract

Global climatic impacts of El Niño are sensitive to details of the surface warming of the equatorial Pacific Ocean, which vary between each El Niño event. The ability to predict the differences in pattern of anomalous ocean temperatures is explored for two prominent types of El Niño, traditional cold tongue events that have maximum surface warming in the eastern Pacific, and warm pool events that have maximum warming in the central Pacific. We assess seasonal predictions of the two types of El Niño using the Australian Bureau of Meteorology coupled ocean-atmosphere seasonal forecast model. Prediction of the major differences in pattern of anomalous ocean surface temperature between the two types of El Niño is limited to less than 1 season lead time, which is much shorter than for prediction of the occurrence of El Niño but which does have important practical application for prediction of regional climate. Improved understanding of the mechanisms of warm pool events and reduction of systematic model biases of the mean state and the coupled modes of variability in the Pacific warm pool/cold tongue should lead to improved skill for predicting regional climate variability associated with El Niño. Copyright 2009 by the American Geophysical Union.