Seasonal distribution of suspended sediments in the water northeast to Shandong Peninsula and its controlling factors

Based on the characteristics of suspended matter, such as sediment content, turbidity, temperature and salinity, acquired in the summer and winter of 2018 in the water northeast to the Shandong Peninsula, we studied the seasonal variation of suspended sediment and it’s controlling factors. The results show that the turbidity varies from 0.2 to 37.8 FTU in summer, 1.5 to 100.1 FTU in winter, of which both are high on the bottom and low on the surface and high in the east and low in the west. Concerning water temperature, it is obviously stratified in summer, high on the surface and low on the bottom. However, there is no obvious changes as far as salinity is considered. In the winter time, both the temperature and salinity show a transition from the low temperature and low salinity water mass near the shore to the high temperature and high salinity water mass off the coast on plane, and evenly mixed in vertical direction. The distribution of suspended sediment content is controlled by various factors, such as tide, wave, thermocline, temperature and salinity fronts. In summer, affected by the thermocline vertically, the suspended sediments in bottom water are difficult to move into the upper layer, while tidal mixing and wave differentiation will accelerate the exchange of suspended sediment between the near shore and the far shore areas. However, the content of surface suspended matter is significantly higher in winter, because of the intensification of vertical mixing by strong wind and waves. The temperature and salinity front, formed by the coastal current and the Yellow Sea warm current, will block the exchanges of suspended sediments between water masses.