Multi-Model Ensemble for Seasonal Prediction at Environment Canada

Environment Canada has been in the business of producing seasonal forecasts using the Multi-Model Ensemble (MME) approach since 1995. Nowadays, the MME approach is widely spread but typically uses model contributions from different producing centres instead of only one center. Current examples of these multi-center MMEs for seasonal forecasting include the WMO, APCC, NMME and EUROSIP MMEs. During that 20 years period, successive versions of the EC's seasonal forecasting system have drawn upon “models of opportunity” that were developed for other purposes by EC's climate and meteorological modeling centers. This talk will describe the origins of this single-center/multi-model approach, and its evolution through configurations consisting of two and subsequently four 2-tier models in the 1990s and 2000s, to the current Canadian Seasonal to Interannual Prediction System (CanSIPS). The latter is based on two global climate models, CanCM3 and CanCM4, that employ common ocean, sea ice and land components coupled to two versions of CCCma's atmospheric model. Lessons learned concerning the efficiency of this multi-model approach will be discussed.