Sea‐cliff retreat and shore platform widening: steady‐state equilibrium?
Sea‐cliff retreat and shore platform widening: steady‐state equilibrium?
复制标题
海崖后退和海岸平台加宽：稳态平衡？
DOI：
10.1002/esp.3422
复制
发表时间：
2013
影响因子：
3.3
通讯作者：
A. Hutchinson
中科院分区：
文献类型：
--
作者：
M. Dickson;H. Ogawa;P. Kench;A. Hutchinson
我们在微潮海岸的渐进式悬崖后退的背景下挑战稳态平衡的概念。海浪在接近水平海岸平台的突然向海边缘处或附近破裂，然后由于湍流和摩擦而迅速失去高度。概念模型假设波高随离平台边缘的距离呈指数衰减，并且在海平面稳定的情况下平台边缘不发生侵蚀。这些假设结合起来，形成了全新世悬崖退缩的稳定状态。我们认为这种模式并不普遍适用。最近的数据表明：(1)波高指数衰减不是最合适的波衰减概念模型；(2)由于只考虑重力波频率下的波能，稳态模型忽略了次重力波可能的形成作用。在这里，我们提请注意可能的机制，通过这些机制，亚重力波可能会在比现有概念模型所能想象的更大的距离（和更长的时间尺度）上驱动悬崖后退。版权所有©2013 John Wiley & Sons， Ltd
We challenge the notion of steady‐state equilibrium in the context of progressive cliff retreat on micro‐tidal coasts. Ocean waves break at or close to the abrupt seaward edge of near‐horizontal shore platforms and then rapidly lose height due to turbulence and friction. Conceptual models assume that wave height decays exponentially with distance from the platform edge, and that the platform edge does not erode under stable sea‐level. These assumptions combine to a steady‐state view of Holocene cliff retreat. We argue that this model is not generally applicable. Recent data show that: (1) exponential decay in wave height is not the most appropriate conceptual model of wave decay; (2) by solely considering wave energy at gravity wave frequencies the steady‐state model neglects a possible formative role for infragravity waves. Here we draw attention to possible mechanisms through which infragravity waves may drive cliff retreat over much greater distances (and longer timescales) than imaginable under the established conceptual model. Copyright © 2013 John Wiley & Sons, Ltd.