Sediment Transport and Dispersal Pattern from the Bohai Sea to the Yellow Sea

Under the influence of seasonal variation of the Huanghe sediment discharge and the hydrodynamic conditions (e.g. wave height), the suspended sediment concentration (SSC) spatial pattern featured evident seasonal variability. The SSC in wintertime was approximately ten times higher than that in summertime and the high SSC was identified in the southern Bohai Sea around the Yellow River. Here based on the observation data in May and November, 2012, data retrieved from MODIS imageries and the ocean current data from HYCOM, we discovered the sediment dispersal pattern and the annual net sediment flux also presented evident seasonal variability. During wintertime, the prevailing strong northerly winds and its related high waves resuspended the sediment along the coast of the Huanghe Delta and the sediment, as enhanced by the coastal current, was further transported to the Laizhou Bay along its western coast and then escaped from the Laizhou Bay through its eastern side before being ultimately exported to the Yellow Sea through the southern Bohai Strait. The wintertime contributed approximately 4.84 Mt of suspended sediment flux to the Yellow Sea, which was one order higher than that in summertime. In summertime, the less energetic environment together with the stratified water column was unfavorable to the sediment export to the Yellow Sea. As a result, the sediment delivered by the Huanghe to the sea in summertime was mostly accumulated within the subaqueous delta and only fine-grained sediment might be transported to the central Bohai Sea owing to the facilitation of river plume and then exported to the Yellow Sea through the upper water-layer of middle Bohai Strait. In summertime, the Huanghe delta might function as a sink to accumulate large sediment delivered by Huanghe, whereas in wintertime, it would perform as a primary source to provide suspended sediment for the Yellow Sea.