Implications of Using Global Digital Elevation Models for Flood Risk Analysis in Cities
Implications of Using Global Digital Elevation Models for Flood Risk Analysis in Cities
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DOI：
10.1029/2020wr028241
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发表时间：
2020-10
影响因子：
5.4
通讯作者：
F. McClean;R. Dawson;C. Kilsby
中科院分区：
文献类型：
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作者：
F. McClean;R. Dawson;C. Kilsby
随着城市人口的增长，准确描述城市和建成区的洪水风险变得越来越重要。全球数字高程模型（GDEM）最近在全球范围内实现了大范围的洪水风险分析，但其准确性及其对城市洪水风险建模的影响尚未得到充分研究。我们使用五种星载 GDEM 产品和一种机载 LIDAR 产品来比较洪水范围、水文过程线、深度和水动力模拟之间的影响。使用卡莱尔（英国）历史洪水事件的基准观测来评估每次模拟的准确性。结果表明，GDEM 模拟的准确度明显低于基于机载激光雷达的模拟。没有 DEM 在所有指标上都优于其他 DEM； MERIT DEM 是洪水范围的最佳预测器，但 TanDEM-X 在流量方面表现最佳。然而，GDEM 模拟的洪水影响始终被高估，比 LIDAR 模拟高 2 到 3 倍。在获得高分辨率、准确的全球 DEM 之前，应同时使用多种产品，以量化和传达完整的不确定性范围，以确保洪水风险管理决策不会被误导。
As urban populations grow, it is increasingly important to accurately characterize flood risk in cities and built up areas. Global digital elevation models (GDEMs) have recently enabled flood risk analysis at broad scale and worldwide, but their accuracy and its impact on modeled flood risk in cities has not been fully investigated. We compare flood extents, hydrographs, depths, and impacts between hydrodynamic simulations, using five spaceborne GDEM products and an airborne LIDAR product. Benchmark observations of a historical flood event in Carlisle (UK) were used to assess the accuracy of each simulation. GDEM simulations are shown to perform significantly less accurately than the airborne LIDAR‐based simulations. No DEM outperforms the others across all metrics; the MERIT DEM is the best predictor of flood extent, but TanDEM‐X performs best for discharge. However, the impacts of flooding from GDEM simulations are consistently overestimated, 2 to 3 times higher than those from LIDAR simulations. Until a high resolution, accurate, global DEM is available, multiple products should be used concurrently to enable the full uncertainty range to be quantified and communicated, to ensure flood risk management decisions are not misinformed.