Development of a regional ocean-atmosphere-wave coupled model and its preliminary evaluation over the CORDEX East Asia domain

In this study, a regional ocean-atmosphere-wave coupled model was developed using the Ocean Atmosphere Sea Ice Soil (OASIS) version 3 coupler and applied to the Coordinated Regional Downscaling Experiment (CORDEX) Phase 1 East Asia domain. The impacts of the non-breaking surface wave-induced mixing Bv on the model performance were investigated. The inclusion of the surface wave model enhanced the vertical mixing in the upper 100m of the ocean and deepened the simulated ocean mixed layer. The too-shallow ocean mixed layer in the simulation without surface waves was reduced in some places, e.g. over the Bay of Bengal. The coupling of the surface wave model also reduced the cold biases of the ocean temperature in the lower 30m of the ocean over the southern Northwest Pacific. Due to the shallower ocean mixed layer depth in summer, the effects of Bv were stronger in summer than in winter. For the monsoon simulation, the wave-coupled simulation favoured an enhanced East Asian summer monsoon due to the colder simulated sea surface temperature (SST) over the Northwest Pacific, whereas in winter, the warmer simulated SST over the area north of 40 degrees N led to a slightly stronger winter monsoon over Far East Asia than did the no wave simulation.