Predictability of Two Types of El Niño Assessed Using an Extended Seasonal Prediction System by MIROC

AbstractPredictability of El Nino–Southern Oscillation (ENSO) is examined using ensemble hindcasts made with a seasonal prediction system based on the atmosphere and ocean general circulation model, the Model for Interdisciplinary Research on Climate, version 5 (MIROC5). Particular attention is paid to differences in predictive skill in terms of the prediction error for two prominent types of El Nino: the conventional eastern Pacific (EP) El Nino and the central Pacific (CP) El Nino, the latter having a maximum warming around the date line. Although the system adopts ocean anomaly assimilation for the initialization process, it maintains a significant ability to predict ENSO with a lead time of more than half a year. This is partly due to the fact that the system is little affected by the “spring prediction barrier,” because increases in the error have little dependence on the thermocline variability. Composite analyses of each type of El Nino reveal that, compared to EP El Ninos, the ability to predict C...