Nearshore sediment pathways and potential sediment budgets in embayed settings over a multi-annual timescale
Nearshore sediment pathways and potential sediment budgets in embayed settings over a multi-annual timescale
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多年时间尺度内海湾环境中的近岸沉积物路径和潜在沉积物预算
DOI：
10.1016/j.margeo.2020.106270
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发表时间：
2020
期刊：
影响因子：
2.9
通讯作者：
Valiente N
中科院分区：
文献类型：
--
作者：
Valiente N
在世界岩石海岸线中，有湾的海滩占很大比例，但很少有研究关注被岩石海岸分开的有湾海滩之间的沿岸沉积物交换。在这里，我们调查的近岸泥沙输运动力学沿着15公里的延伸，英格兰西南部康沃尔郡北部的海湾海岸线，使用Delft 3D。数值模拟（耦合波浪和潮汐）进行计算的主要环流模式和沉积物通量，包括数量级的海湾之间的沉积物旁路，为广泛的模式和极端的波浪条件。结果表明，极端事件导致：（i）多海湾环流和大型裂流形成，其中沿岸流在下波扇区中转向离岸（0.7 m s− 1，深度>20 m）;（ii）大旁路率（103- 104 m3天− 1旁路）;（iii）交换延伸到超过岬角底部的深度。中高涌浪期间的增生阶段与顺时针海湾内环流有关，模拟的海流导致长海湾（> 103 m3日-1沿岸）向南重新分布。这种环流模式与较浅和较宽海岬周围的显著绕行率（102- 103 m3 day −1）相结合。沿下滨面的沉积物通量沿着的预测是基于模拟的沉积物通量和近海波浪条件之间的相关性（r> 0.92），提供了对多年时间尺度上的潜在沉积物收支的见解。在假设沉积物供应无限的情况下，海岬周围的年绕行率介于103和105 m3 y − 1之间，大部分输送主要发生在高能事件期间。因此，这里提出的计算的潜在沉积物通量的大小对较长时间尺度（>10年）的海岸演变有影响，特别是沿着沉积物匮乏的海岸线。
Embayed beaches constitute a large proportion of the world's rocky coastlines, but there is a paucity of studies focusing on the longshore sediment exchange between embayed beaches separated by rocky stretches of coast. Here, we investigate the nearshore sediment transport dynamics along a 15-km stretch of the embayed coastline of north Cornwall, SW England, using Delft3D. Numerical simulations (coupled wave and tide) are conducted to compute major circulation modes and sediment fluxes, including order of magnitude for sediment bypassing between bays, for a wide range of modal and extreme wave conditions. Results indicate that extreme events cause (i) multi-embayment circulation and mega-rip formation where an alongshore current is deflected offshore (0.7 m s−1at >20 m depth) in the down-wave sectors, (ii) large bypassing rates (103–104m3day−1bypassing) and (iii) exchanges extending to depths that exceed the base of the headlands. Accretionary phases over moderate-high swell periods were associated with clockwise intra-embayment circulation with simulated currents inducing redistribution towards the south in the long embayments (>103m3day−1longshore). This circulation mode is combined with significant bypassing rates around the shallower and wider headlands (102–103m3day−1). Predictions of sediment fluxes along the lower shoreface are based on the correlation between the modelled sediment fluxes and offshore wave-conditions (r> 0.92), providing insights into the potential sediment budget over multi-annual timescales. Hindcasted yearly bypassing rates around the headlands range between 103and 105m3y−1under an assumption of unlimited sediment supply, with the bulk of the transport occurring mainly during high energy events. Hence, the magnitude of the computed potential sediment fluxes presented here has implications for coastal evolution at longer timescales (>10 years), especially along sediment-starved coastlines.
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DOI：
10.1002/2016jf003823
发表时间：
2016
期刊：
Journal of Geophysical Research: Earth Surface
影响因子：
--
作者：
W. Ridderinkhof;H. Swart;M. Vegt;P. Hoekstra
通讯作者：
P. Hoekstra
岬角沙子绕过 — 巴西南部圣卡塔琳娜岛北岸内湾海滩净沉积物输送的量化
DOI：
--
发表时间：
2016
期刊：
影响因子：
--
作者：
G. V. D. Silva;E. Toldo;A. Klein;A. Short;C. Woodroffe
通讯作者：
C. Woodroffe
影响因子：
4.4
作者：
Huisman, B. J. A.;Ruessink, B. G.;Stive, M. J. F.
通讯作者：
Stive, M. J. F.
洋流、波浪和沉积物在 Pt. 岬角周围输送。
影响因子：
2.3
作者：
D. George;J. Largier;C. Storlazzi;M. Robart;B. Gaylord
通讯作者：
B. Gaylord
波浪和潮汐对沉积物贫乏、充满活力和大潮汐大陆架上的残余沙运移的影响
DOI：
10.1029/2018jc014861
发表时间：
2019
期刊：
Journal of Geophysical Research: Oceans
影响因子：
--
作者：
E. King;Daniel Conley;G. Masselink;N. Leonardi;R. McCarroll;T. Scott
通讯作者：
T. Scott