Study on the Sediment Transport Flux and Mechanism in the Bohai Strait at the Tidal and Monthly Scales in Summer

Abstract

Based on the data of tidal currents and suspended sediment concentrations observed synchronously at 11 stations in the Bohai Strait lasting for 25 hours, the temporal and spatial variations of currents and suspended sediment concentrations in the Bohai Strait in summer were analyzed. The Study preliminarily discussed the transport mechanism, transport trend and transport flux of suspended sediments in summer, using flux-mechanism decomposition method and numerical simulation. The suspended sediment transport was mainly controlled by advection and next influenced by vertical net circulation, while resuspension is relatively weak in Bohai Strait. The single-width fluxes of investigation stations varied from 3.8 to 89.1 gm−1 s−1, with the maximum value in Miaodao Strait. The suspended sediment transport trends in Laotieshan channel along the vertical section are obviously distinct. The waters mainly flow out of the Bohai Sea in surface layer, while into the Bohai Sea in bottom layer. However, the transport trends of other channels in the centre and south are consistent vertically. The sediments in the Bohai Strait follows the transport pattern of moving outward from the south and inward from the north in summer, i.e., the sediments are carried out of the Bohai Sea through the Laotieshan channel, while into the Bohai Sea through other channels. And the outflow flux exceeds the inflow flux in August with the net water flux of 1.4×1010 m3, basically same as the deliveries of the rivers into the Bohai Sea. Moreover, the suspended sediment flux is 0.33 Mt under the action of tidal residual currents in the Yellow Sea in August.