Eroded sediment can return to the subaerial beach through onshore sandbar migration, thus understanding this process is key for rebuilding coastal morphology. While offshore sandbar migrations are fairly predictable based on wave conditions alone, landward migrations are less predictable and more dependent on sandbar morphometrics. In this study, monthly collected topographic and bathymetric data from August 2014 to September 2018 were analyzed and related to the incoming wave conditions to investigate the control of sandbar location and morphometry on the landward migration process. Four distinct onshore sandbar migration modes were identified, primarily governed by the sandbar crest location and size (volume and height), and the preceding cumulative wave energy. A cross-shore distance of 150 m equivalent to ~3 m depth was defined as a boundary for the fate of the sandbar during the landward migration process. Sandbar welding (SW; Mode I) occurred during low-energy conditions after a moderately energetic winter (cum Pt ≤ 50 kWm⁻¹) when the sandbar (of up to 1 m height and ~ 100 m³m⁻¹) was located shoreward from the cross-shore boundary. A large sandbar (> 100 m³m⁻¹; > 1 m height) that formed offshore from the boundary during a highly-energetic winter (cum Pt >50 kWm⁻¹) turned into a terrace-bar (STT; Mode II) in a subsequent very low-energy period. A terrace-bar of ~100 m³m⁻¹ located near the boundary (~ 3 m depth) became a sandbar (TST; Mode III) during moderately energetic conditions at the beginning of the winter. Sandbar splitting (SS; mode IV) occurred during low-energy conditions when a sandbar of ~100 m³m⁻¹ situated offshore from the boundary; the outer section flattened and followed a net offshore migration cycle while the inner section migrated shoreward. This study highlights the need for considering sandbar morphometric properties in addition to the preceding wave conditions to adequately predict the shoreward migration process of the sandbar.

侵蚀的沉积物可通过陆上沙洲迁移而返回到海底海滩，因此了解这一过程是重建沿海形态的关键。虽然仅凭波浪情况就可以很好地预测海上沙洲的迁移，但陆上的迁移则较难预测，而更依赖于沙洲的形态。在这项研究中，分析了2014年8月至2018年9月每月收集的地形和测深数据，并将其与入射波条件相关联，以研究沙洲位置和形态对陆运过程的控制。确定了四种不同的陆上沙洲迁移模式，主要由沙洲波峰的位置和大小（体积和高度）以及先前的累积波浪能决定。相当于〜3 m深度的150 m跨岸距离被定义为沙洲向陆迁移过程中命运的边界。中等强度的冬季（Pt≤50 kWm）过后的低能状态下发生了沙洲焊接（SW； I模式）^-1）时，沙洲（高度不超过1 m，〜100 m ³ m ^-1）位于从跨岸边界向岸的位置。在高强度的冬天（Pt> 50 kWm ^-1时）从边界海上形成的大型沙洲（> 100 m ³ m ^-1；> 1 m高）变成了梯田（STT；模式II）在随后的低能耗时期。在冬季开始时，在中等强度的条件下，靠近边界（深度约3 m）的〜100 m ³ m ^-1的露台吧变成了沙洲（TST；模式III）。沙洲分裂（SS;模式IV）在低能状态下发生，沙洲约为100 m ³ m ^-1位于边界境外；外部变平并遵循净的海上迁移周期，而内部则向岸迁移。这项研究强调，除了前面的波浪条件外，还需要考虑沙洲的形态特征，以充分预测沙洲的向岸迁移过程。