BRGM, 3, av. Claude Guillemin, BP 36009, 45060, Orleans Cedex 2, France.
BRGM, French Geological Survey, Pessac, France.
Sci Rep. 2019 Jan 10;9(1):42. doi: 10.1038/s41598-018-37017-4.
Sandy shorelines are constantly evolving, threatening frequently human assets such as buildings or transport infrastructure. In these environments, sea-level rise will exacerbate coastal erosion to an amount which remains uncertain. Sandy shoreline change projections inherit the uncertainties of future mean sea-level changes, of vertical ground motions, and of other natural and anthropogenic processes affecting shoreline change variability and trends. Furthermore, the erosive impact of sea-level rise itself can be quantified using two fundamentally different models. Here, we show that this latter source of uncertainty, which has been little quantified so far, can account for 20 to 40% of the variance of shoreline projections by 2100 and beyond. This is demonstrated for four contrasting sandy beaches that are relatively unaffected by human interventions in southwestern France, where a variance-based global sensitivity analysis of shoreline projection uncertainties can be performed owing to previous observations of beach profile and shoreline changes. This means that sustained coastal observations and efforts to develop sea-level rise impact models are needed to understand and eventually reduce uncertainties of shoreline change projections, in order to ultimately support coastal land-use planning and adaptation.
沙质海岸线不断演变，经常威胁到建筑物或交通基础设施等人类资产。在这些环境中，海平面上升将加剧海岸侵蚀，其程度仍不确定。沙质海岸线变化预测继承了未来平均海平面变化、垂直地面运动以及影响海岸线变化可变性和趋势的其他自然和人为过程的不确定性。此外，海平面上升本身的侵蚀影响可以使用两种根本不同的模型来量化。在这里，我们表明，到 2100 年及以后，到目前为止还很少量化的这一不确定性来源，可以解释海岸线预测变化的 20%至 40%。这是在法国西南部四个相对不受人类干预影响的对比沙质海滩上证明的，由于先前对海滩剖面和海岸线变化的观测，因此可以对海岸线预测不确定性进行基于方差的全局敏感性分析。这意味着需要持续进行沿海观测和努力开发海平面上升影响模型，以了解并最终减少海岸线变化预测的不确定性，从而最终支持沿海土地利用规划和适应。
