ABSTRACT

Vietnamese cities are highly vulnerable to urban flooding as a consequence of climate change and rapid urbanisation. In this study, current and future pluvial urban flood hazard was assessed for Ha Tinh city. Climate scenarios were obtained after statistical downscaling by applying a quantile-perturbation approach on ensembles of 170 global and 20 regional climate models. Flood impact analysis was based on the 1D-2D dual drainage modelling approach. Extreme daily rainfall intensities are projected to increase by 5 to 20%, whereas wet day frequency will decrease with some uncertainty. Larger changes in rainfall intensities were obtained for the finer scale climate models. Under the 95% upper limit scenario for future rainfall intensities (2071–2100), a 20-year intensity in the current climate would become a 2-year storm in the future and the flood extent is projected to increase by 30–40%. This indicates a need for climate adaptation measures and sustainable future urban planning.

摘要

由于气候变化和快速的城市化，越南城市极易遭受城市洪灾的影响。在这项研究中，对河廷市当前和未来的城市洪水灾害进行了评估。在对统计规模缩小后，通过对170个全球和20个区域气候模型的集合应用分位数扰动方法，获得了气候情景。洪水影响分析基于1D-2D双排水建模方法。极端的每日降雨强度预计将增加5％至20％，而潮湿的天气频率将有所降低。对于更精细的气候模型，降雨强度的变化更大。在未来降雨强度（2071-2100）的上限为95％的情况下，当前气候中20年的强度将在未来变成2年的风暴，预计洪水泛滥的程度将增加30-40％。这表明需要采取气候适应措施和可持续的未来城市规划。