Predictions of enso with a coupled Atmosphere-Ocean general circulation model

Abstract

Predictions of ENSO are described by using a coupled atmosphere-ocean general circulation model. The initial conditions are created by forcing the coupled system using SST anomalies in the tropical Pacific at the background of the coupled model climatology. A series of 24-month hindcasts for the period from November 1981 to December 1997 are carried out to validate the performance of the coupled system. Corre-lations of SST anomalies in the Nino3 region exceed 0.54 up to 15 months in advance and the rms errors are less than 0.9°C. The system is more skillful in predicting SST anomalies in the 1980s and less in the 1990s. The model skills are also seasonal-dependent, which are lower for the predictions starting from late autumn to winter and higher for those from spring to autumn in a year-time forecast length. The prediction, begin-ning from March, persists 8 months long with the correlation skill exceeding 0.6, which is important in pre-dictions of summer rainfall in China. The predictions are succesful in many aspects for the 1997–2000 ENSO events.