By using the Princeton Ocean Model

circulation and thermal structure of the South China Sea (SCS) in the domain 98° -126° E

3° S-26° N are simulated on real topography data. The upper half of the right vertical boundary is set as an open boundary. The simulation starts from a motionless ocean

and average temperature and salinity data of January are used as the initial field. Driven by 12 different monthly averaged wind fields

the model runs steadily for four model years. Simulation results are recorded from the beginning of the third year. The temporal and spatial evolution of the circulation and thermal structure is analyzed. The results show that the SCS is dominated by a big cyclone type circulation in winter and by an anticyclone type in summer. During spring and autumn the monsoon reverses direction. The circulation is influenced by the monsoon of the last season and transits to the typical circulation type of the next season. It consists of multiple vortices. Additionally

the climate and environmental conditions can influence the characteristics of the circulation and thermal structure.