Numerical Simulation Of Suspended Sediment Transport Process And Its Mechanism Of The Bohai Sea,Yellow Sea And East China Sea

The Bohai Sea,Yellow Sea and East China Sea(BYECS)is one of the continental shelf areas with the highest suspended sediment concentration(SSC)in the world,as well as complex surface sediment types and abundant of rivers inflow.This area is affected by East Asian monsoon and circulation.The distribution and transportation of suspended sediment in BYECS not only control the evolution of submarine topography and seafloor morphology,but also show great impacts on marine life,marine environment and the coastal structures.Transport processes of the suspended sediment during April 2008 to December 2012 in BYECS are simulated using the University of New South Wales sediment(UNSW-sed)model embedded into the MASNUM(marine science and numerical model).The simulated distribution of SSC is consistent with both that of measured data from�Offshore Comprehensive Survey and Evaluation Project of China�(908 Project)and the remote sensing data.The conclusions are as follows:High SSC areas are around the Yellow River Estuary,Yangtze River Estuary,and the Subei shoal.Their distribution range is the widest in winter and smallest in summer,whereas in transitional form during spring and autumn.The distribution of suspended sediments is influenced by seasonal change of wind speed.The changes of wind speed show strong impact on the SSC in the areas with shallow water,whereas in the case of deeper layer and/or with short period of wind speed change,the wind activities impose limited influence on SSC.Transport of suspended sediment from the Bohai to Yellow Sea is controlled by the Yellow Sea Cold Water Mass in summer and the Yellow Sea Warm Current in winter.The high salinity and low temperature water mass that clustered at the bottom layer forms strong thermocline and halocline in summer,which limits the upward transport of high concentration suspended sediment.The direction of suspended sediment transport in Yangtze Estuary and along the Subei shoal is mainly affected by the wind direction.The annual net flux from the Bohai Sea to the Yellow Sea,from the Northern Yellow Sea to the Southern Yellow Sea and from the Yellow Sea to the East China Sea are 220�10~6 t?631�10~6 t and709�10~6 t,respectively.Suspended sediment transported from the Bohai Sea to the Yellow Sea is mainly via the Laotieshan Waterway and the Dengzhou Waterway in spring.Suspended sediment transported from North Yellow Sea to the South Yellow Sea is mainly at the west of 123.6�E in late autumn and winter.Suspended sediment transported from the Yellow Sea to the East China Sea is via most area in winter.The results of SSF from different representative cross-section indicate that:there are resuspended sediments in mud area around the Shandong peninsula and the Subei shoal.Resuspended sediments from the mud area around Shandong are transported southward under the control of the Shandong coastal current.Under the current conditions,this model obtained optimal degree of the mathematical details.However,this model is set without taking the following variables into account:the actual river suspended sediment input,the variety of surface sediment types and the major tides.Thus,more detailed measured data is needed to quantitively verified these results.