TEMPORAL AND SPATIAL VARIATION OF SUSPENDED SEDIMENT CONCENTRATION IN THE NEARSHORE WATERS OF WESTERN YANTAI AND ITS TRANSPORT CHARACTERISTICS IN WINTER

Based on the simultaneous observation of currents and suspended matters in spring and neap tides at six stations in the coastal waters of Yantai Port in December 2017, this paper studied the temporal and spatial variation in suspended sediment concentrations. The transport flux of suspended matter was calculated, and the transport mechanism of suspended sediment under tidal currents discussed. The results show that the suspended sediment content in the spring tide is greater than that in the neap tide; and the concentration of suspended matter at each station has 2~4 peaks during the spring tide period, whereas that in the neap tide is more complicated and lack of regularity. The change in suspended sediment generally lags behind the flow rate change for 1~2 hours. From the view of plane distribution, the concentration of suspended sediment at different stations in the study period is quite different, and the difference in neap tide period is rather small. In the vertical direction, however, the suspended sediment content in each layer of the spring and neap tides has little change, and the stratification phenomenon is not obvious. The advection transport of the water in the study area dominates the suspended sediment transport, while the vertical net circulation plays a supporting role, and the contribution of other sediment transport modes is rather small. The net transport direction and residual flow of suspended sediment in the study area are roughly the same. The contribution of the vertical net circulation to the suspended sediment transport during the spring tide period is slightly larger than that during the neap tide period. The contribution of the advection transport in the neap tidal period to the suspended sediment transport is slightly greater than that during the spring tide period, and the influence of the fluctuation of spring and neap tides on the sediment transport is significant in the area.