Forecasting coastal overtopping at engineered and naturally defended coastlines
Forecasting coastal overtopping at engineered and naturally defended coastlines
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DOI：
10.1016/j.coastaleng.2020.103827
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发表时间：
2021-03-01
影响因子：
4.4
通讯作者：
Ely, Nick
中科院分区：
文献类型：
--
作者：
Stokes, Kit;Poate, Tim;Ely, Nick
随着海平面上升和沿海地区的继续发展，沿海洪水对沿海社区构成越来越大的风险。波浪爬高可使海洋垂直延伸数米，特别是在陡峭的砾石海滩上，而越浪是沿着暴露于高能波浪条件下的海岸线发生沿海洪水的关键因素。然而，由于需要高分辨率的近岸水位和波浪条件，最新的海岸剖面和海防信息，以及可以稳健地预测一系列海岸剖面类型的越浪的模型或公式的可用性，因此很少尝试对波浪越浪进行业务预测。在这里，我们已经开发和测试了一个有效的预报系统，提前三天为整个1000公里的英格兰西南部海岸线，称为SWEEP-OWWL，这是能够预测波浪爬高高度和越浪量沿着充满活力的和macrotidate海岸线，具有embayed，桑迪，砾石，和工程区域提供业务预警。现有的洪水预警系统使用的过程为基础的流体动力学模型XBeach，但由于计算成本，已诉诸人口使用离线模拟和沿海测深只有一个单一的实现查找表。相反，SWEEP-OWWL运行在“实时”使用一套计算效率高的经验变浅，打破，爬高，并在184个沿海剖面越浪方程，被迫与水动力信息从区域1公里的光谱波和水动力模型。重要的是，预报系统可以更新与最新的海岸剖面数据，没有额外的计算成本，这表明，在某些情况下，以提高预测的越浪率的精度的一个数量级。与西南部实时流媒体网络摄像头对洪水事件的视觉观察相比，该系统以97%的准确率正确预测了是否存在波浪漫顶，并显示出区分低风险和高风险事件的技能。可靠的预报浪越可以大大提高沿海社区的能力，以准备和减轻对生命，财产和基础设施的风险，在沿海洪水事件，和开发的系统表明，这可以实现使用一个单一的台式PC为整个地区具有自然和人为的海防。
As sea level rises and development of the coastal zone continues, coastal flooding poses an increasing risk to coastal communities. Wave runup can contribute many meters to the vertical reach of the sea, especially on steep gravel beaches, and wave overtopping is a key contributor to coastal flooding along coastlines exposed to energetic wave conditions. However, operational forecasting of wave overtopping has rarely been attempted due to the need for high-resolution inshore water levels and wave conditions, up-to-date coastal profile and sea defence information, and availability of models or formulae that can robustly predict overtopping for a range of coastal profile types. Here, we have developed and tested an efficient forecasting system for providing operational warnings up to three days in advance for the entire 1000 km coastline of southwest England, called SWEEP-OWWL, which is capable of predicting wave runup elevation and overtopping volumes along the energetic and macrotidal coastline, featuring embayed, sandy, gravel, and engineered regions. Existing flood warning systems have used the process-based hydrodynamic model XBeach, but due to the computational cost, have resorted to populating look-up tables using off-line simulations and only a single realisation of the coastal bathymetry. Instead, SWEEP-OWWL runs in 'real-time' using a computationally efficient suite of empirical shoaling, breaking, runup, and overtopping equations at 184 coastal profiles, forced with hydrodynamic information from a regional 1-km spectral wave and hydrodynamic model. Importantly, the forecast system can be updated with the latest coastal profile data with no extra computational cost, which is shown to improve the accuracy of predicted overtopping rate by an order of magnitude in some cases. Compared to visual observations of flooding events from live streaming webcams around the southwest, the system correctly predicted the presence or absence of wave overtopping with 97% accuracy and showed skill in differentiating between low and high hazard events. Reliable forecasts of wave overtopping could considerably enhance a coastal community's ability to prepare and mitigate against the risk to life, property, and infrastructure during coastal flooding events, and the developed system shows that this can be achieved using a single desktop PC for entire regions featuring both natural and man-made sea defences.