Fate of three major rivers in the Bohai Sea: A model study

Huanghe (Yellow River), Haihe and Liaohe are three major rivers flowing into the Bohai Sea and account for more than 80% of the freshwater and land-drained material inputs annually. The fate of three rivers in the seawaters correlates with the transport and distribution of the riverine sediments and nutrients, and further exerts a profound influence on the local marine ecosystem dynamics. Therefore, the evolution of the river plumes under the influence of the freshwater buoyancy, the tidal forcing and the wind stress are examined using a three-dimensional primitive equation ocean circulation model, independently and jointly. It is found that both tide and wind stirring can deteriorate the stabilization of the water column caused by the freshwater buoyancy; however, the processes are different. The tide stirring originates from the seafloor due to the bottom friction as the tidal wave propagates into the shallow waters, and then the turbulent kinetic energy dissipates upward. On the other hand, the wind stirring proceeds in the up–down direction. The influences of different winds on the evolution of the river plumes are also examined. Since the situation of each river mouth is different, the wind influence is also distinct. At last, the fate of three major rivers driven by the combined tidal forcing and climatology winds is reproduced, and the simulated salinity distribution shows a reasonable agreement with that observed, meaning that the river plume evolution plays a crucial role in shaping the salinity distribution in BS.

► We model the river plumes, which are driven by the freshwater buoyancy, tidal mixing and wind stress. ► We examine the influence of different mechanisms on the evolution of the river plumes. ► We examine the fate of three major rivers in BS, which are under the combined influence of tide, wind and the Coriolis force. ► The evolution of the river plumes plays a crucial role in shaping the salinity distribution in BS.