Adaptation strategies to pluvial urban flood risk under UKCP18 climate change scenarios

预计随着未来气候变化，与夏季对流风暴和冬季锋面风暴相关的强降雨的频率和影响将增加。更高强度的降雨给城市地区带来了严重的洪泛挑战，由于现有的基础设施和发展，这限制了缓解方案。地方当局需要在洪水缓解战略中考虑气候变化，目前使用区域气候模型（RCM），如英国气象局发布的UKCP 09气候预测（Rabb等人，2017）。这些模型模拟提供了预测，如温度，降雨量和湿度等变量可能会在气候变化下在区域一级发生变化。与传统的全球气候模式（GCM）相比，RCM具有许多优势;它们提供的信息具有更高的空间分辨率（与20- 100公里相比只有几公里），并且能够解释较小尺度的大气环流，例如与对流雷暴相关的大气环流，从而产生更真实的降雨和洪水强度和频率（McGregor，1996; Rabb，2017）。UKCP 18气候预测建立在UKCP 09的基础上。UKCP 18的分辨率更高，提供了更复杂的气候预测，在区域尺度上提供了更详细的信息（Rabb et al，2017）。RCM数据与水文和水力建模一起，使人们能够更好地了解气候变化将如何影响径流，河流水文和洪水风险。尽管在气候建模方面取得了这些重大进展，但在如何将这种增强的分辨率气候理解转化为洪水影响以及如何在现有洪水评估方法和模型中最好地利用这些新数据方面仍然存在重大研究空白。该项目将专门解决这一研究空白。沿着传统的防洪方案，可持续城市排水系统（SUDS），以及最近的自然洪水管理（NFM）方法，现在都被用作缓解方案，以解决增加的洪水风险。然而，考虑到真实的防洪计划的复杂性，如何在给定的城市集水区最好地利用这种选择组合并不总是显而易见的。除了探索气候变化预测外，该项目还将研究真实的防洪计划中使用的一系列缓解方案，并由合作伙伴提供工程级洪水模型。该博士项目为学生提供了一个独特的机会，可以整合两个相关的研究领域，在前沿气候建模和洪水风险评估的界面上工作。CASE合作伙伴WSP（一家主要的工程咨询公司）和利兹市理事会（领导当地洪水管理局）的支持提供了与防洪专业人员合作和学习的机会，同时最大限度地发挥研究的影响。学生应该对与气象，气候和洪水风险有关的环境问题有浓厚的兴趣。他们还将在定量科学方面有很强的背景（数学，物理，工程，环境科学）和天赋，或熟悉，编程和科学计算。学生将在Mark Trigg博士的监督下工作（洪水风险和NFM），Christian Berretta博士（SUDS和排水），Cathryn Birch博士（气候建模），Paul Lambert（WSP，洪水和排水）和Matt舍伍德（LCC，洪水风险）。学生将直接受益于利兹大学、WSP和利兹市理事会之间的现有合作关系。高水平的培训将提供专业科目专业洪水和排水建模软件和方法。

The frequency and impact of heavy rainfall associated with summer convective storms and winter frontal storms is projected to increase with future climate change. Higher intensity rainfall poses significant pluvial flooding challenges in urban areas, which have constrained mitigation options due to existing infrastructure and developments. Local authorities need to account for climate change in flood mitigation strategies and currently use regional climate models (RCM's) such as the UKCP09 climate projections issued by the Met Office (Rabb et al, 2017). These model simulations provide projections of how variables such as temperature, rainfall, and humidity may change at a regional level under climate change. RCMs have a number of advantages over more traditional Global Climate Models (GCMs); they provide information at a higher spatial resolution (a few kilometres compared to 20-100km) and they are able to account for smaller scale atmospheric circulations such as those associated with convective thunderstorms, producing more realistic rainfall and flood intensities and frequencies (McGregor, 1996; Rabb, 2017). The UKCP18 climate projections build on UKCP09. UKCP18 has an even finer resolution and provides more sophisticated climate projections, with greater detail at regional scales (Rabb et al, 2017). The RCM data, alongside hydrology and hydraulic modelling, enables an enhanced understanding of how climate change will impact streamflow, river hydrology and flood risk. Despite these significant advances in climate modelling, there are still major research gaps in terms of how this enhanced resolution climate understanding translates into flooding impacts, as well as how best to utilise this new data in existing flood assessment methodologies and models. This project will specifically address this research gap. Along with traditional flood defence options, sustainable urban drainage systems (SUDS), and more recently natural flood management (NFM) methodologies are all now being utilised as mitigation options to addressing increased flood risk. However, how best to utilise this combination of options in a given urban catchment is not always obvious, given the complexities of real flood defence schemes. As well exploring climate change projections, this project will also look at a range of mitigation options used in real flood defence schemes, with engineering grade flood models provided by partners.This PhD project provides a unique opportunity for a student to integrate two linked research areas, working at the interface of cutting edge climate modelling and flood risk assessment. The support of CASE partner WSP (a major engineering consultancy) and Leeds City Council (Lead local flood authority) provides the opportunity to work with and learn from flood defence professionals, while maximising the impact of the research. The student should have a strong interest in environmental problems related to meteorology, climate and flood risk. They will also have a strong background in a quantitative science (math, physics, engineering, environmental sciences) and a flair for, or a good familiarity with, programming and scientific computing.The student will work under the supervision of Dr Mark Trigg (Flood Risk and NFM), Dr Christian Berretta (SUDS and drainage), Dr Cathryn Birch (Climate modelling), Paul Lambert (WSP, Flooding & Drainage), and Matt Sherwood (LCC, Flood Risk). The student will benefit directly from an existing partnership between the University of Leeds, WSP and Leeds City Council. High level training will be provided in specialist subjects professional flood and drainage modelling software and methods.