Cold water mass (CWM) is a distinct hydrologic phenomenon in summer in worldwide continental shelf seas. CWM can significantly affect circulation patterns and biogeochemical fluxes, and thus marine ecosystems. Nonetheless, limited studies have documented the seasonal migration of the CWM thermal front and the corresponding sediment distribution in the South Yellow Sea (SYS). This study used field observations and a well-validated numerical model to investigate the evolution of the CWM in the SYS; and its potential effect on the seasonal and spatial variations of suspended sediment distribution and transport. Remarkable seasonal variation in the CWM and its thermal front were observed from spring to fall. Numerical model results indicated that the reductions in current velocities and bottom shear stresses were induced by the baroclinic effect of the thermal front. Hence, the offshore sediment transport existed near the thermal front. The variations of intensity and location of the thermal front are capable of inducing the variation of suspended sediment concentration and sediment transport without winds. Sediment transport direction was slightly adjusted by winds. Northerly wind drove sediment transport seaward from the Chengshan Cape to the central SYS as the thermal front moved seaward in fall. Besides, the seaward extension of highly turbid water near the Subei coast in fall was also caused by wind-induced currents and waves. The thermocline of the CWM restricted the sediment from efficiently dispersing upward to the surface, which promoted the formation of the central SYS mud area. The understanding about the effect of CWM with its thermal front on the sediment transport in this study should benefit further exploring other CWMs on the continental shelf seas.

夏季，在全球大陆架海中，冷水量（CWM）是一种独特的水文现象。CWM可显着影响循环模式和生物地球化学通量，进而影响海洋生态系统。但是，有限的研究记录了CWM热锋的季节性迁移和南黄海（SYS）中相应的沉积物分布。这项研究使用现场观察和经过充分验证的数值模型来研究SYS中CWM的演变。及其对悬浮泥沙分布和运输的季节和空间变化的潜在影响。从春季到秋季观察到CWM及其热锋的明显季节性变化。数值模型结果表明，热锋的斜压效应导致了流速和底部切应力的降低。因此，近海沉积物运输存在于热锋附近。热锋强度和位置的变化能够引起悬浮泥沙浓度和无风泥沙输送的变化。风对泥沙的输送方向进行了微调。随着热锋在秋天向北移动，北风驱使沉积物从成山海角向SYS的海域运移。此外，秋季苏北海岸附近浑浊的水向海扩展也是由风流和波浪引起的。CWM的温跃层限制了沉积物有效地向上扩散到表面，这促进了中央SYS泥浆区的形成。在这项研究中对CWM及其热锋对沉积物运移的影响的理解应该有助于进一步探索大陆架海面上的其他CWM。