Coastal cliff behaviour: Observations on the relationship between beach levels and recession rates
Coastal cliff behaviour: Observations on the relationship between beach levels and recession rates
复制标题
沿海悬崖行为：海滩水位与衰退率之间关系的观察
DOI：
10.1016/j.geomorph.2008.02.010
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发表时间：
2008
期刊：
影响因子：
3.9
通讯作者：
E. M. Lee
中科院分区：
文献类型：
--
作者：
E. M. Lee
海滩消散波浪能量，并调节悬崖脚受到波浪攻击的频率。英国北诺福克和萨福克郡海岸沿着更新世软岩悬崖的海滩水平和悬崖衰退率之间的关系已经建立。结果表明，在十年的时间尺度上，有一个非线性增长的平均衰退率的高水位线（HWM）以上的海滩剖面面积减少。海滩水位的微小变化可导致衰退率的显著差异。海滩水位单位变化对退水率的影响取决于初始海滩水位。在逐年的基础上，可以将海滩水位和后退关系划分为一系列具有特征行为类型的区域。在低的海滩水平，有很高到极高的衰退，具有相当大的变化，而在高的海滩水平，几乎是零衰退，有限的变化。它的结论是，历史衰退率的产品都在过去的强迫事件和悬崖海滩状态的变化。历史速率的外推法可能是极不可靠的，除非它得到对悬崖-海滩系统的动态行为和观测期间的能量输入的理解的支持。
Beaches dissipate wave energy and regulate the frequency that the cliff foot is subject to wave attack. The relationship between beach levels and cliff recession rates has been established for Pleistocene soft rock cliffs along the North Norfolk and Suffolk coasts, UK. The results suggest that over a decadal timescale, there is a non-linear increase in the average recession rate as the beach profile area above High Water Mark (HWM) decreases. Small changes in beach level can result in significant differences in the recession rates. The impact of a unit change in beach level on the recession rate depends on the initial beach level. On a year-by-year basis, it is possible to divide the beach level and recession relationship into a series of zones with characteristic types of behaviour. At low beach levels there is high to extremely high recession with considerable variability, whereas at high beach levels there is almost zero recession with limited variability. It is concluded that historical recession rates are the product of both the past forcing events and changes in cliff–beach state. Extrapolation of historical rates can be extremely unreliable unless it is supported by an understanding of the dynamic behaviour of the cliff–beach system and the energy inputs over the observation period.