Simulation of the circulation in the Yellow Sea and the East China Sea using a high resolution wave-circulation-tide coupled model
Abstract:
The model is applied to study the circulation pattern of the summer Yellow Sea. The simulated tide, temperature and salinity agree the observation well, the simulated current filed is also confirmed by observation. A comprehensive three-dimensional circulation structure of the Yellow Sea in summer is put forward based in the model result and the observation data:
(1) In the surface layer (0-4m), driven by wind the prevailing current direction is northeastward.
(2) The upper layer (4-40m) is dominated by a basin scale anti-clockwise (cyclonic) gyre, diagnostic analysis of the momentum balances and sensitive study shows the cyclonic circulation in the upper layers is mainly a quasi-geotropic flow along tidal-induced temperature front, it is also strengthened by the Eulerian residual tidal currents. The stream function of the YS shows the net circulation of the YS is anti-clockwise (cyclonic).
(3) In the bottom layer (below 40m) the water diverges from the YS trough towards seashore and the divergence velocity is strong along the temperature front area. The baroclinic pressure gradient force due to the strong tidal induced temperature front in the bottom layer drives the water to diverge. There also exists a weak southward current. Tidal residual current and the northward wind transport in the surface layer may contribute to the formation southward flow in the bottom layer.
The model is also used to simulate the Kuroshio in the East China Sea. The simulated path, volume and velocity of the Kuroshio in the East China Sea agree with the observation well. The secondary circulation such as the gyres and the reverse flow along the Kuroshio edge are also simulated in the model result. The mechanism of the the gyres and the reverse flow along the Kuroshio edge will be studied using the model.