The typical seasonal (summer and winter) residual circulation in the Bohai Sea is studied with the ODEM three-dimensional model. The averaged tidal current distributions and tide-induced residual current are presented. The effects of seasonal wind on tidal residual current and local thermally-driven current on wind-driven and tide-induced current are analyzed. The corresponding mechanisms are discussed. The results also present the month-averaged energy flow rate for Bohai Strait and the three sections at the mouth of Liaodong Bay, Bohai Bay and Laizhou Bay for different cases.
The Bohai Sea is a semi-enclosed basin. It is rather shallow except for the submerged valley near the north of Bohai Strait approximately 100 km wide and the maximum depth of 70 m which connects the Bohai Sea with Yellow Sea. The Bohai Sea contains three main Bays, Liaodong Bay in the northeast, Bohai Bay in the west and Laizhou Bay in the south. In Liaodong Bay, the averaged water depth is 30m. The topography of water bottom in Bohai Bay is rather flat. The water depth in most part is less than 20m except for the north part where the water depth is more than 30m. Laizhou Bay is the shallowest Bay in the the Bohai Sea. In most part of the Bay, the water depth is less than 10m, the deepest depth is 18m. The water depth of central basin approximately in triangle shape changes from 20m to 40m. Quite a big number of interests and studies from different researchers have been given to the Bohai Sea since 1980's. Firstly, it is so shallow with a mean depth of 18 m. Therefore, the circulation system induced by periodical tidal current, wind induced current and density driven current is so complicated and changeable under the changing forcings.