Video monitoring systems (VMS) have been used for beach status observation but are not effective for examining detailed beach processes as they only measure changes to the shoreline and backshore. Here, we extracted longshore sediment transport (LST) from VMS in order to investigate long- and short-term littoral processes on a pocket beach. LST estimated by applying one-line theory, wave power, and the oblique angle of incident waves were used to understand shoreline changes caused by severe winter storms. The estimated LST showed good agreement with the shoreline changes because the sediments were trapped at one end of the pocket beach and the alongshore direction of transported sediments was corresponded to the direction of LST. The results also showed that the beach that was severely eroded during storms was also rapidly recovered following the evolution of LST, which indicates that the LST may play a role in the recovery process while the erosion was mainly caused by the cross-shore transport due to storm waves. After the beach was nourished, beach changes became more active, even under lower wave energy conditions, owing to the equilibrium process. The analysis presented in this study could be applied to study inhomogeneous beach processes at other sites.

中文翻译：

---

利用视频监测海岸线数据估算近岸泥沙运移

视频监视系统（VMS）已用于观察海滩状态，但对于检查详细的海滩过程无效，因为它们仅测量海岸线和后岸的变化。在这里，我们从VMS中提取了近岸沉积物运输（LST），以研究口袋海滩上的长期和短期沿海过程。通过应用一线理论，波浪功率和入射波的倾斜角估计的LST被用来了解由严冬风暴引起的海岸线变化。估计的LST与海岸线变化有很好的一致性，因为沉积物被困在小袋海滩的一端，并且沿岸方向输送的沉积物与LST的方向相对应。结果还表明，随着LST的演化，暴风雨中遭受严重侵蚀的海滩也得以迅速恢复，这表明LST可能在恢复过程中发挥了作用，而侵蚀主要是由于跨岸运输造成的。风暴波。在海滩得到营养之后，由于平衡过程，即使在较低波能条件下，海滩变化也变得更加活跃。本研究中提出的分析可用于研究其他地点的非均匀海滩过程。