Assessment of subseasonal prediction skill of the KMA GloSea5 hindcast experiment

This study evaluated the basic performance of the subseasonal prediction using an ensemble hindcast runs for 20 years (1991-2010) produced by KMA GloSea5. The KMA GloSea5 is global prediction system for subseasonal-to-seasonal time scale, based on the fully-coupled atmosphere, land, ocean, and sea-ice model. 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, error diagnostics related to precipitation, and prediction skill of major climate variability. The major results show the overestimated precipitation over the western Pacific. Precipitation errors related to the enhanced convection processes, it leads to decreased incoming surface heat fluxes by clouds. As a result, SST can be decreased by cloud-radiation processes as well as ocean mixing processes. This study includes the evaluation and the identification of the systematic biases in the global prediction model. Also it focuses on the prediction skill of East Asian summer and winter monsoon with its interaction between tropics or arctic climate, which are major drivers of weather and climate variability in East Asia.