Apcc’s Multi-Model Ensemble Predictions for Subsesonal-to-Seasonal Timescales

Abstract:

The APEC Climate Center (APCC) is a leading climate information service provider and research institute that serves the 21 APEC member economies and the broader international community. Since 2007, APCC has issued operational monthly rolling three-month forecasts based on the well-validated multiple model ensemble (MME) prediction system. Currently, 14 prominent operational climate centers and research institutes from nine APEC member economies participate in the APCC operational MME prediction by routinely providing their predictions in the form of ensembles of global forecast fields. Various MME methods implemented in APCC’s MME system were compared with a simple averaged MME (with equal weightings), for predicting seasonal mean temperature and precipitation one-month ahead. The results indicate that the simple averaged MME consistently outperforms the multiple regression-based MMEs, when considering all aspects of the predictions from operational prediction systems (i.e., in different variables, regions, seasons) whereas the calibrated MME shows the capability to reduce errors and improve forecast skills in a large proportion of cases.

In 2013, APCC has also begun to provide forecast information service for the boreal summer intraseasonal oscillation (BSISO). The BSISO prediction system includes monitoring, forecast, and validation. The forecast is contributed by five different models from four operational centers in collaboration with the CAS/WCRP Working Group on Numerical Experimentation (WGNE) Madden Julian Oscillation (MJO) Task Force. As demonstrated in this study, the BSISO forecast information can be useful for predicting summer monsoon onset and activity within the East Asia region. Verification of the BSISO forecasts during 2013 shows a similar level of skill for the main BSISO mode (BSISO1) compared to the MJO, but less for the 2nd mode (BSISO2). APCC will develop a methodology relevant to the BSISO MME and the outcome will be available in the coming years.