The East China Sea (ECS) inner shelf is highly impacted by tropical cyclones. Due to the limited availability of observations, the sediment dynamics and associated sedimentary process under the impact of typhoons are still poorly understood. In this study, a high-resolution unstructured-grid FVCOM model was employed to investigate the rapid responses of sediment dynamics on the ECS inner shelf to the passage of Typhoon Chan-hom in July 2015. The results indicated that there was an evident asymmetry in sediment dynamics around the typhoon track. During the typhoon, sediments were resuspended in nearshore area and transported downwind with increasing southwestward and seaward sediment flux. The gear-like sediment delivery presented a ratchet effect that induced an evident spatial asymmetry in responses of sediment dynamics and shelf sedimentation to the short-lived typhoon event. The coastal upwelling normally existing in summer was intermittently blocked by the passage of typhoon, and rapidly transited to downwelling, which substantially enhanced the cross-shelf sediment transport. As a result, severe erosions were mainly occurred near the typhoon track within 20-m isobaths, in contrast to newly formed sedimentary layers (~10 cm in thickness) in areas far south of the typhoon track and around the 50-m isobaths. The spatial asymmetry of sedimentary response to the typhoon passage is therefore of importance to locating sediment records that well preserved the typhoon signals. The ratchet effect we proposed provided reasonable interpretations of the spatially asymmetric responses of shelf sedimentations in the northern Gulf of Mexico and the central Great Barrier Reef shelf to tropical cyclones, respectively.

东海 (ECS) 内陆架受热带气旋影响很大。由于观测资料有限，台风影响下的沉积动力学和相关沉积过程仍知之甚少。本研究采用高分辨率非结构化网格 FVCOM 模型研究了 2015 年 7 月 ECS 内陆架沉积物动力学对台风 Chan-hom 过境的快速响应。台风路径周围的沉积物动力学。在台风期间，沉积物重新悬浮在近岸区域并随着向西南和向海的沉积物通量增加而顺风运移。齿轮状沉积物输送呈现棘轮效应，导致沉积物动力学和陆架沉积对短寿命台风事件的响应出现明显的空间不对称性。夏季正常存在的沿海上升流被台风通过间歇性阻塞，并迅速转变为下降流，大大增强了跨大陆架的沉积物运输。因此，严重侵蚀主要发生在 20 米等深线内的台风路径附近，而台风路径以南和 50 米等深线附近地区新形成的沉积层（厚度约 10 厘米）则相反。因此，沉积对台风通道响应的空间不对称性对于定位良好保存台风信号的沉积记录具有重要意义。