Beach and sea-cliff dynamics as a driver of long-term rocky coastline evolution and stability
Beach and sea-cliff dynamics as a driver of long-term rocky coastline evolution and stability
复制标题
海滩和海崖动力学作为长期岩石海岸线演化和稳定性的驱动因素
DOI：
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发表时间：
2011
期刊：
影响因子：
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通讯作者：
A. Murray
中科院分区：
文献类型：
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作者：
P. Limber;A. Murray
我们使用基于海滩和海崖之间相互作用的探索性分析和数值模型来研究千年时间尺度上的岩石海岸线演变。在模型中，波浪驱动的海崖退缩是海滩宽度的非线性函数，其中沉积物磨损使悬崖退缩最大化，而海滩沉积物缺乏或沉积物过多（阻止波浪到达海崖）则使悬崖退缩最小化。当海崖退缩时，海滩沉积物会通过波浪驱动的沉积物输送产生并分布在沿岸，而当地海滩的宽度决定了未来悬崖退缩的速度。数值实验表明，通过这种相互作用，岩石海岸线可以达到平衡配置，即使在海崖岩性不存在沿海变化的情况下，岬角和海湾也能随着时间的推移保持稳定。此外，平衡海岸线配置，或岩石岬角与悬崖背靠的小型海滩的沿岸比例，可以通过分析进行预测。初步测试表明，预测在质量上与实际景观相符。
We investigate rocky coastline evolution over millennial time scales using exploratory analytical and numerical models based on interactions between beaches and sea cliffs. In the models, wave-driven sea-cliff retreat is a nonlinear function of beach width, where cliff retreat is maximized by sediment abrasion and minimized by either a lack of beach sediment or too much sediment (which prevents waves from reaching the sea cliff). As sea cliffs retreat, beach sediment is produced and distributed alongshore by wave-driven sediment transport, and local beach widths determine future cliff retreat rates. Numerical experiments indicate that through such interactions, rocky coastlines can reach an equilibrium configuration where headlands and embayments remain stable through time, even in the absence of alongshore variations in sea-cliff lithology. Furthermore, the equilibrium coastline configuration, or the alongshore proportion of rocky headland to cliff-backed pocket beach, can be predicted analytically. Initial tests suggest that predictions match well qualitatively with actual landscapes.