The superposed sawtooth model of suspended sediment concentration in the Yellow River subaqueous delta based on in-situ observation

The time series of waves, tides, currents, temperatures and turbidities were measured for 134 days in the Yellow River subaqueous delta with a submarine in situ tripod equipped by various instruments. The samples taken from the study site are analyzed in the laboratory for sediment grain size and the relationship between the suspended sediment concentration and turbidity. The sediment studied is mainly composed of silt, and a good linear relationship between the suspended sediment concentration and turbidity has observed. The suspended sediment concentration varies from 2 g/L to 4 g/L in the Yellow River subaqueous delta. Both the in-situ observation and the shear stress calculation show that the sharp rise in suspended sediment concentration is attributed to the episodic high waves, and the quotidian currents are responsible for the periodic fluctuation in suspended sediment concentration. Above all, a superposed sawtooth model of suspended sediment concentration influenced by waves and currents is proposed and the shear stress can explain the reason why episodic waves account for large sawteeth and currents are responsible for the small sawteeth.