Dynamic variability and seasonal predictability in an intermediate complexity coupled ocean-atmosphere model

We formulate a numerically efficient coupled ocean-atmosphere model. It consists of a global atmosphere and a Pacific basin ocean, with two dynamical levels in each component. The model has a realistic climatology and displays El Niño,Southern oscillation variability at the observed frequencies. In hindcasts over the period 1981 to 2000, the model displays good skill out to seven months in forecasting the tropical upper ocean temperatures and zonal current anomalies. The most skilful forecasts occur for those initialised during June to November. Skilful predictions for the atmospheric fields generally only extend to one month, but can be as much as three months during major El Niño,Southern oscillation events.