The South China Sea (SCS) is deep marginal sea connected to the western Pacific Ocean mainly through Luzon Strait. Observational studies showed that an annual mean three-layer water exchange structure is present in strait, composed of an upper inflow, an intermediate outflow and a deep inflow, and all three components exhibit pronounced seasonal variations. In this study, we developed an ocean circulation modeling system for the marginal seas of the Asian Pacific region. The system is built on MITgcm (MIT general circulation model), configured with a resolution of 1/12° and realistic bathymetry, forced with atmospheric reanalysis data, and simulating for the period 1979-2018. The model reproduces a seasonal exchange structure in Luzon Strait consistent with observations. We further analyze the seasonal changes in the overturning circulations in the SCS and their connections to the western boundary currents in the west Pacific.

South China Sea,Overturning Circulation,Modeling