Hourly change in sediment plume at the Yellow River mouth during the water-sediment regulation

Since the water sediment regulation (WSR) was put into operation in 2002, most of the Yellow River sediment has been deposited in a confined near-shore zone as a result of hypopycnal plume. On the basis of GOCI satellite images collected in 2011, 2012 and 2013, we analyzed the hourly changes in sediment plume at the Yellow River mouth through the inversion to suspended matter concentrations. Wind fields along with tide data during the satellite-observation period were comprehensively analyzed, and the hydrodynamic regime in the mouth area was numerically modeled to uncover the influence forces of these changes. The results show that the hourly changes in sediment plume can be classified into two types: 1) one-orientation changes—the sediment plume moves gradually towards a definite direction (landwards or seawards); 2) back-and-force movement—the sediment plume shifts landwards or seawards in the first few hours and then moved backwards. In addition, the total suspended mater (TSM) at the Yellow River mouth varies both spatially and temporally, reflecting an intensive interaction between different hydrodynamic processes. For some sites, the hourly changes in TSM may exceed 100 mg/L. One-orientation changes are primarily controlled by tidal currents with a minor influence from river input, whereas back-and-force movements are controlled by the changes of ebb and flood tide. Shear front generated near the river mouth is also believed an important process behind the back-and-force movement of sediment plume.