Modelling the Erosion in the Scottish Coasts using the Process-Based Approach: Historic Validation and Projection of the Climate Change Scenarios

苏格兰20%的人口居住在距离海岸1公里的范围内，预计未来将面临更高的侵蚀和洪水风险。苏格兰政府通过国家海岸变化评估项目（NCCA）评估了苏格兰海岸的侵蚀脆弱性。评估采用了海岸侵蚀敏感性模型（CESM），这是一种基于参数的方法，根据地形、岩头高程、邻近程度、波浪暴露、海岸防御和历史沉积物供应来估计海岸线变化。制作的全国比例尺地图显示了147个地点的历史海岸线演变情况，还提到了受到威胁的资产。然而，未来的预测只是定位可能遭受侵蚀的地点，并不一定表明这些地点正在遭受或将受到侵蚀。我的博士研究旨在解决这一差距，使用基于过程的模型提供更现实的海岸线变化预测。与CESM相比，它需要更多的计算工作，但通过可视化气候变化和人类干预对海岸的影响机制，使决策者受益。海平面上升、波浪气候和风暴等海洋状态正在因气候变化而改变。预计未来极端事件将更加频繁，因此导致海岸侵蚀的风险更大。此外，在某些情况下，海岸防御并没有阻止侵蚀，而是将威胁转移到其他地区。基于过程的模型将被用来理解这一现象，Delft3D（开源），XBeach（开源），和UNIBEST是在这项研究中的核心工具，著名的海岸建模由Delegate开发。这些套件已经在荷兰（Sand Engine）和韩国海岸进行了测试，在长期和风暴条件下复制海岸线变化方面表现良好。在本研究中，将以一些具有独特特征的关键海岸作为研究案例。在这些地区进行的研究，不但可阐明个别地点的海岸演变过程，亦可为其他环境相若的地点提供参考。这一系列的研究预计在三至四年内完成。第一年用于审查研究问题，与前沿研究人员建立合作关系，并收集相关数据。第二年和第三年的重点是验证模型，并继续预测气候变化和人类干预的影响。论文和考试将在第四年年初完成。这项研究将说明苏格兰海岸在气候变化和更频繁的风暴中的弹性。此外，还将为每个感兴趣的领域提出最有效的适应措施。将着重指出进程和参数办法的优缺点，从而有可能在制订战略性海岸线管理计划时相互结合。

Twenty percent of the Scottish population live within 1 km from the coast and in the future is expected at a higher risk of erosion and flooding. The Scottish Government have assessed the erosion vulnerability of the Scottish Coasts through the National Coastal Change Assessment project - NCCA. The assessment employed the Coastal Erosion Susceptibility Model (CESM), a parametric-based approach estimating the shoreline changes based on topography, rockhead elevation, proximity, wave exposure, coastal defence, and historic sediment supply. The produced national scale map is showing the historical shoreline evolution at 147 sites, also mentioning the assets in threat. However, the future projections are only locating the sites that can experience erosion, not necessarily indicate that the sites currently undergo or will be eroded.My doctorate research aims to address this gap, providing a more realistic shoreline change projection using the process-based model. Compare to the CESM, it requires more computational effort but benefiting the decision-maker by visualizing the mechanism of climate changes and human interventions in impacting the coast. The sea states, such as sea-level rise, wave climates, and storms are being altered by climate change. Extreme events are expected to become more frequent in the future and therefore result in a bigger risk of coastal erosion. Moreover, the coastal defence in some cases does not stop the erosion, rather it relocates the threat to other areas. The process-based model will be used to understand this phenomenon.The Delft3D (open-source), XBeach (open-source), and UNIBEST are the core tools in this research, well-known for coastal modelling develop by Deltares. These suites have been tested in the Netherlands (Sand Engine) and the Korean Coast, performing well in replicating the shoreline change both in long-term and storms condition. In this research, some critical coasts with distinctive characteristics will be taken as a study case. Investigation on these areas not only will elucidate the coastal processes at the specific sites, but also act as a rule of thumb for other sites with a similar environment.This series of research is designed to be completed in three to four years. The first year is allocated for examining the research question, building a collaboration with the forefront researcher, and collecting the relevant data. The second and third years focus on validating the model and proceeding to project the impact of climate changes and human interventions. The thesis and examination are to be finished in the early of the fourth year.This research will illustrate how resilient the Scottish Coasts in the changing climate and the more frequent storms. Also, the most effective adaptation measures will be proposed for each area of interest. The advantages and disadvantages of the process and parametric-based approach will be underlined, opening up the possibility of coupling in formulating the strategic shoreline management plans.