Seasonal variation of the Yellow Sea cold water mass and its impact on suspended sediment transport

The Yellow Sea Cold Water Mass (YSCWM) is a typical hydrological phenomenon in the Yellow Sea in summer, it has significant impacts on regional circulation system, material transport, and ecosystem. Based on the observation data of hydrological and suspended sediment concentration (SSC) in different seasons in the Yellow Sea, combined with HYCOM model data, the seasonal variations of the YSCWM and its impact on suspended sediment transport were investigated. The findings indicate notable seasonal variations in the YSCWM: emerging in spring, reaching its peak in summer, weakening from late summer to early autumn, and disappearing in winter. The hydrographic structure of the YSCWM also experiences adjustments as manifested by the reduction in vertical temperature gradient, the increase in thermocline depth from 20 m to 40m, and the movement of temperature front at boundary from 121°E to 123°E. The presence of thermocline and temperature fronts restricts the vertical diffusion and horizontal transport of suspended sediments across layers and fronts. These seasonal variations of the YSCWM lead to the expansion of the nearshore dispersion area of suspended sediments, the increase in SSC at the bottom of the YSCWM, and the decrease in SSC above the YSCWM.