Sediment dynamics in the Bohai Sea under extreme weather: advances and prospects

Extreme weather events are major drivers of coastal geomorphic change, and understanding the mechanisms governing sediment-dynamic responses to these events is important for resilience-oriented coastal management. Drawing on field observations, satellite remote sensing, and numerical simulations, this paper systematically reviews research progress on sediment dynamic responses in the Bohai Sea under extreme weather conditions. The review is structured around the process chain of sediment entrainment and resuspension, reorganization of the spatiotemporal distribution of suspended sediment, and abrupt changes in sediment fluxes and source-sink evolution. Existing studies indicate that: ① Wave-current coupling increases bottom shear stress to several to several tens of times the background level, while seabed liquefaction increases erosion rates by a factor of 5-10; together, these processes are the primary drivers of large-scale sediment resuspension. ② During extreme events, suspended sediment concentrations increase by one to two orders of magnitude relative to normal conditions, and the dispersal of high-turbidity zones is strongly controlled by wind field. ③ Typhoons and cold surges operate through markedly different hydrodynamic forcing mechanisms: a single typhoon may account for 5%—33% of the annual net sediment flux, whereas cold surges act mainly through persistent cumulative forcing. Both can rapidly reconfigure source-sink patterns. On this basis, a positive-feedback framework of “event forcing, geomorphic adjustment, and response evolution” is proposed. Future research should prioritize observations of the rheological properties of high-concentration fluid mud, assessment of the cumulative geomorphic effects of clustered extreme events, and development of intelligent forecasting systems to support resilience-oriented governance of the Bohai coastal zone.