Modeling suspended sediment distribution in continental shelf upwelling/downwelling settings

Numerical experiments were carried out to evaluate the physical effects of upwelling/downwelling on the suspended sediment concentration (SSC) on continental-shelves. The results show that (1) because the upwelling or downwelling velocity tends to be of the same order of magnitude as the settling velocity of suspended sediment, various SSC distribution patterns are possible, depending on the relative importance of the velocities; (2) the presence of upwelling can enhance the SSC; and (3) in an upwelling/downwelling system, maximum concentrations may be situated in the middle of the water column, if the settling velocity is larger than the upwelling velocity. Hence, the physical processes associated with upwelling/downwelling are relevant to the SSC distribution observed over the mud patch near Cheju Island, East China Sea. Furthermore, a qualitative analysis indicates that the presence of upwelling/ downwelling in the overlying water column increases the accumulation rate at the seabed.