A Newly Developed APCC SCoPS and Its Prediction of East Asia Seasonal Climate Variability

The Asia Pacific Economic Cooperation (APEC) Climate Center (APCC) in-house model (Seamless Coupled Prediction System: SCoPS) has been newly developed for operational seasonal forecasting. SCoPS has generated ensemble retrospective forecasts for the period 1982–2013 and real-time forecasts for the period 2014–current. In this study, the seasonal prediction skill of the SCoPS hindcast ensemble was validated compared to those of the previous operation model (APEC Climate Center Community Climate System Model version 3: APCC CCSM3). This study validated the spatial and temporal prediction skills of hindcast climatology, large-scale features, and the seasonal climate variability from both systems. To examine the fidelity of the system to reproduce and to forecast phenomena, this study focused on three important aspects: systematic biases of hindcast climatology, interannual variability of large-scale circulation, and prediction skill of major climate variability. The first one includes the evaluation and the identification of the systematic biases in the global prediction model, judged from long-term averaged states with many ensembles. The second one shows the global divergent field at the upper troposphere in contributions from the Hadley, Walker and monsoon circulations, using a seasonal mean velocity potential field. The third one focuses on the prediction skill of ENSO, East Asian summer and winter monsoon, AO, which are major drivers of weather and climate variability in East Asia.