We study the compound flooding processes that occurred in Hurricane Florence (2018), which was accompanied by heavy precipitation, using a 3D creek-to-ocean hydrodynamic model. We examine the important role played by barrier islands in the observed compound surges in the coastal watershed. Locally very high resolution is used in some watershed areas in order to resolve small features that turn out to be critical for capturing the observed high water marks locally. The wave effects are found to be significant near barrier islands and have contributed to some observed over-toppings and breaches. Results from sensitivity tests applying each of the three major forcing factors (oceanic, fluvial, and pluvial) separately are succinctly summarized in a “dominance map” that highlights significant compound effects in most of the affected coastal watersheds, estuaries, and back bays behind the barrier islands. Operational forecasts based on the current model are being set up at NOAA to help coastal resource and emergency managers with disaster planning and mitigation efforts.

中文翻译：

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佛罗伦萨飓风期间复合洪水过程的跨尺度研究

我们使用 3D 小溪到海洋流体动力学模型研究了在伴随强降水的飓风佛罗伦萨（2018 年）中发生的复合洪水过程。我们研究了屏障岛在沿海流域观察到的复合浪涌中发挥的重要作用。在一些流域区域使用局部非常高分辨率，以解析对局部捕获观察到的高水位线至关重要的小特征。发现波浪效应在屏障岛附近很显着，并导致了一些观察到的过度覆盖和破裂。从灵敏度测试的结果施加每个三大强迫因子（海洋，河流，和洪积）的分别简明扼要地总结在“优势地图”中，突出了在大多数受影响的沿海流域、河口和屏障岛后面的后海湾的显着复合效应。NOAA 正在建立基于当前模型的业务预测，以帮助沿海资源和应急管理人员进行灾害规划和减灾工作。