Improving flood risk assessment in flashy catchments under a changing climate

我的博士学位将建立在以前的工作在纽卡斯尔大学收集了分小时降雨量数据从英国各地的仪表，并使用此来重新分析降雨事件的轮廓，从而导致六个雨型曲线的推导形状更新设计降雨剖面的目的。我的博士学位最初旨在调查极端降雨事件，以评估降雨剖面形状与温度的关系，以便将其用作气候变化可能对未来降雨产生影响的指标。除了从收集的测量记录中观察到的降雨数据的评估外，我的博士学位还将分析和比较对流允许模型模拟结果的降雨剖面。气候建模的进步使得高分辨率模型能够代表小尺度效应，如云中的对流，从而提供更准确的预测。尽管计算要求意味着这更局限于局部地区而不是全球，但这对于我的博士学位来说是可以接受的，因为我的博士学位重点是英国。博士学位的下一阶段将使用ReFH 2软件从更新的降雨剖面中获得洪水过程线六个设计雨型，并将其与洪水研究报告（FSR）中现有的两个雨型进行比较，这是英国水文分析的当前标准形状。这两个FSR配置文件都有一个对称的，单峰钟形，不随风暴的持续时间或位置，但有一个更广泛的，较低的形状为冬季风暴，和一个峰值，较高的形状为夏季风暴。六个更新的剖面包括三个水平变化的前加载，中心（对称）和后加载的形状和两个垂直变化，提供更多的峰值和更少的峰值版本的每个剖面负载。洪水过程线测试将主要集中在小的、闪光的集水区，因为这些集水区对降雨事件的反应最快，特别是可能受到气候变化高度影响的短时强降雨。预计将使用洪水估算手册（FEH）网络服务中的描述符数据对大约20个集水区进行测试。博士学位的最后阶段将是在水文和/或水力模型模拟中应用降雨剖面，例如纽卡斯尔的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，将对模型地形进行进一步模拟，以反映自然洪水管理干预措施，目的是评估如何最好地使集水区适应气候变化的影响。建议对文献中使用的方法进行审查，以将气候变化应用于洪水风险估计，以便为我的博士学位提供气候变化的应用信息。该博士学位的成果将更新目前对洪水风险的理解，从而有助于为未来的洪水管理项目提供适当的设计风暴的应用信息，并可能有助于指导相关情景的洪水风险评估。

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.