Improving flood risk assessment in flashy catchments under a changing climate

我的博士学位将建立在纽卡斯尔大学以前的工作基础上，纽卡斯尔大学从英国各地的测量仪收集了分小时的降雨量数据，并利用这些数据重新分析了降雨事件轮廓，得出了六种湿度图形状，目的是更新设计的降雨轮廓。我的博士学位最初的目标是研究极端降雨事件，以评估降雨剖面形状与温度之间的关系，以此作为气候变化对未来降雨可能产生的影响的指示。除了评估从收集的量测记录中观测到的雨量数据外，我的博士还将分析和比较允许对流模型模拟结果的雨量廓线。气候模型方面的进步使高分辨率模型成为可能，这些模型可以表示小尺度效应，如云中对流，从而提供更准确的预测。虽然计算要求意味着这更多地局限于局部地区，而不是全球范围，但对于我专注于英国的博士学位来说，这是可以接受的。PHD的下一阶段将是使用ReFH2软件从更新的降雨剖面中提取洪水过程线六种设计雨量线形状，并将它们与洪水研究报告(FSR)中现有的两种雨量线形状进行比较，这两种形状是英国目前用于水文分析的标准形状。这两个FSR剖面都具有对称的单峰钟形，不随风暴持续时间或位置而变化，但对于冬季风暴具有更宽、更低的形状，对于夏季风暴具有更高的形状。六个更新的剖面包括三个水平变化的前载、中心(对称)和后载形状，以及两个垂直变化，提供每个轮廓加载的更多尖峰和更少尖峰版本。洪水过程线测试将主要集中在小而闪耀的集水区，因为这些集水区对降雨事件最敏感，特别是可能受到气候变化高度影响的短而强烈的降雨。预计将使用洪水估计手册(FEH)网络服务的描述符数据对大约20个集水区进行测试。PHD的最后阶段将是将降雨剖面应用于水文和/或水力模型模拟，如纽卡斯尔的SHETRAN、CityCat或HiPIMS软件，以评估不同剖面形状对洪水风险的影响。如果时间允许，将进行进一步的模拟，调整模型地形以反映自然洪水管理干预措施，目的是评估如何最好地调整集水区以适应气候变化的影响。建议对文献中使用的将气候变化应用于洪水风险评估的方法进行审查，以便为我的博士学位提供气候变化的应用信息。本博士论文的成果将提供当前对洪水风险的最新认识，从而有助于为未来洪水管理项目提供适当的设计风暴应用，并可能有助于指导对相关情景进行洪水风险评估以进行测试。

My PhD will build on previous work at Newcastle University which had collected sub-hourly rainfall data from gauges across Great Britain and used this to re-analyse rainfall event profiles resulting in derivation of six hyetograph shapes for the purpose of updating design rainfall profiles. My PhD initially aims to investigate extreme rainfall events to assess how rainfall profile shapes are related to temperature, in order to use this as an indication of the effect climate change may be expected to have on future rainfall. In addition to the assessment of observed rainfall data from the collected gauge records, my PhD will also analyse and compare rainfall profiles from convection permitting model simulation results. Advances in climate modelling have enabled high resolution models which can represent small-scale effects such as convection in clouds and thus give more accurate predictions. Although computational requirements mean this is more limited to local areas than globally, this is acceptable for my PhD which is focussed on Britain. The next stage of the PhD will be to use ReFH2 software to derive flood hydrographs from the updated rainfall profiles six design hyetograph shapes and compare them to the existing two hyetograph shapes from the Flood Studies Report (FSR), which are the current standard shapes for hydrological analysis in Britain. The two FSR profiles both have a symmetric, single-peaked bell-shape, which does not vary with storm duration or location but has a broader, lower shape for winter storms, and a peakier, higher shape for summer storms. The six updated profiles comprise three horizontal variations of front-loaded, centre (symmetrical) and back-loaded shapes and two vertical variations giving more-peaked and less-peaked versions of each of the profile loadings. The flood hydrograph testing will be predominantly focussed on small, flashy catchments since these are most responsive to rainfall events, in particular short, intense rainfall which is likely to be highly affected by climate change. It is anticipated that approximately 20 catchments will be tested, using descriptor data from the Flood Estimation Handbook (FEH) web service. The last stage of the PhD will be to apply the rainfall profiles in hydrological and/or hydraulic model simulations, such as Newcastle's SHETRAN, CityCAT or HiPIMS software, to assess the effect of the different profile shapes on flood risk. If time allows, further simulations will be undertaken with the model terrain adjusted to reflect natural flood management interventions with the aim of assessing how best to adapt catchments for the effects of climate change. It is proposed to undertake a review of methods used in the literature to apply climate change in flood risk estimation in order to inform application of climate change for my PhD. The outputs of this PhD will provide an update to current understanding of flood risk and hence help inform application of appropriate design storms for future flood management projects and potentially contribute to guidance for flood risk assessment on relevant scenarios to test.