In this study, a novel numerical model is first developed, which can simulate compound floods under a framework comprehensively considering the combined effects of tide, river flow, rainfall, and wind. The modelling framework is applied to reproduce an extreme compound flood event in the Pearl River Delta caused by Typhoon Hato (2017). The model is estimated to perform reasonably well, which can yield consistent results compared with observations including winds, water levels, and inundation depths over the study area. Inundation was concentrated on downstream estuaries and floodplains and coastal forcings played a dominant role in this compound event. However, ignoring river and rainfall contributions would result in an underestimation of flood extent and water levels that could be up to 48%. Sensitivity tests indicate that precise calibration of the roughness coefficient is more critical in river and estuarine environments than in land region. This study demonstrates the importance of utilizing an integrative framework to assess and predict compound flooding hazards driven by the effects of tropical cyclones.

中文翻译：

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预测河口地区热带气旋复合洪水灾害的综合模型框架

在这项研究中，首次开发了一种新颖的数值模型，可以在综合考虑潮汐、河水、降雨和风的综合影响的框架下模拟复合洪水。该模型框架用于重现由台风“天鸽”（2017）引起的珠江三角洲极端复合洪水事件。该模型预计表现相当良好，与研究区域的风、水位和淹没深度等观测结果相比，可以产生一致的结果。洪水集中在下游河口和漫滩，沿海强迫在这一复合事件中起主导作用。然而，忽略河流和降雨的贡献将导致洪水范围和水位被低估高达 48%。敏感性测试表明，粗糙度系数的精确校准在河流和河口环境中比在陆地区域中更为重要。这项研究证明了利用综合框架来评估和预测由热带气旋影响引起的复合洪水灾害的重要性。