Sustainable Solutions for Managing Compound Flood Risks under Future Uncertainties: The Case of Shanghai City and the Yangtze River Delta Region

气候变化对长江三角洲地区提出了重大的规划挑战，该地区的城市建设可能是世界上最大的相邻大都市区集中区。长三角都市圈以上海为中心，上海是长江口南岸的特大城市。长江三角洲和上海面临着由海平面上升、极端暴雨、天文大潮、风暴潮和上游洪水引起的复合极端洪水事件。有效缓解长江三角洲地区此类复合事件的潜在破坏性后果，不仅可以挽救该地区的人类生命，也有助于中国的可持续发展和社会稳定。该项目将制定弹性适应措施，以应对长江三峡和上海在气候变化和快速社会经济发展下未来日益增加的洪水风险。我们将根据气候和水动力模型的最新发展，量化未来的复合洪水风险，并评估直接（建筑物、资产和基础设施等的物理损坏）以及由这些复合事件造成的间接损失（沿经济的投入产出链沿着的经济损失）。然后，我们将以上海为重点，评估拟议的减缓和适应方案，并基于增强的稳健决策（RDM）方法，设想2017-2100年期间的可持续解决方案。在这个拟议项目中，英国团队将领导两个工作包（WP），并为其他包做出贡献。英国团队将领导气候变化情景的WP-1，因为英国气象局目前正在定期运行一个数值天气预报（NWP）预报模型，该模型在英国上空具有1.5公里的水平分辨率（UKV模型）。基于这一优势，英国团队将与中国合作伙伴共同开发基于区域气候模式的气候变化情景，以创建长三角地区的高分辨率降雨数据。此外，联合王国小组还将为估计同时发生的极端天气/气候事件（WP 2）的联合分布做出贡献。英国团队将领导关于间接影响评估的WP-4，因为孙来祥教授及其合作者提出了一个具有供应约束的混合投入产出模型，可以有效地评估极端事件对社会经济部门的间接影响。英国团队还将为WP-6潜在解决方案评估做出重大贡献，因为该团队为该项目的稳健决策（RDM）计划和动态适应性政策途径（DAPP）的设计做出了最重要的贡献。这一拟议项目的总体任务和联合王国小组对该项目的贡献都非常符合环境和战略研究委员会关于与环境变化共存的主题。我们的项目对气候变化下的资源挑战和基础设施挑战都有明确的强调，并清楚地认识到工程和物理科学在应对洪水风险管理，水工程，沿海和航道工程以及可持续土地管理等领域的挑战方面可以发挥的重要作用。在建模方面，我们开发了一个综合建模框架，以考虑到从气候变化对风暴和海平面的影响到极端事件造成的物理和经济损失的整个级联因素，从而能够可靠地确定每年的破坏状态概率和防洪途径的综合权衡分析。这一综合的概率分析工具促进了EPSRC在利用高等数学和信息和通信技术对复杂性进行建模方面的使命。

Climate change presents a significant planning challenge for the Yangtze River Delta (YRD) Region, where urban build-up has given rise to what may be the largest concentration of adjacent metropolitan areas in the world. The YRD metropolitan region is centred at Shanghai, a mega city sitting on the south edge of the mouth of Yangtze River. YRD in general and Shanghai in particular face compound extreme flooding events caused by sea level rise, extreme rainstorms, astronomical high tides, storm surge, and upstream floods. To effectively mitigate the potential devastating consequences of such compound events in YRD will not only save human lives in the region but also contribute to sustainable development and social stability in China. This project will develop resilient adaptation measures to address future increasing flood risk under climate change and rapid socioeconomic development in YRD and Shanghai. We will quantify the compound flooding risks in the future based on the latest developments in climate and hydrodynamic modelling, and assess both direct (physical damage of buildings, assets and infrastructures, etc.) and indirect losses (economic losses along the input-output chain of the economy) caused by such compound events. We will then evaluate proposed mitigation and adaptation alternatives with a focus on Shanghai and visualize the sustainable solutions over the period of 2017-2100 based on the enhanced Robust Decision Making (RDM) method.In this proposed project, the UK team will lead two working packages (WPs) and contribute to other packages. The UK team will lead WP-1 on climate change scenarios because the Met Office is currently routinely running a numerical weather prediction (NWP) forecast model with 1.5-km horizontal resolution over the UK (the UKV model). Based on this advantage, the UK team will work with Chinese partners to develop climate change scenario based on a regional climate model so as to create very high resolution rainfall data in the YRD region. In addition, the UK team will also contribute to the estimation of the joint distribution of co-occurring extreme weather/climate events (WP2). The UK team will lead WP-4 on Indirect Impact Assessment because Prof Laixiang SUN and his collaborators have advanced a mixed input-output model with supply constraint to effectively estimate the indirect impact of extreme events on socioeconomic sectors. The UK team will also make significant contributions to WP-6 on Evaluation of Potential Solutions because the team has made the most important contribution to the design on combining the robust decision making (RDM) scheme and the dynamic adaptive policy pathways (DAPP) for this project. Both the overall missions of this proposed project and the contribution of the UK team to the project fit well with the EPSRC's theme on Living With Environmental Change. Our project has a well-specified emphasis on both the resource challenge and the infrastructure challenge under climate change, and shows a clear recognition of the important role that engineering and physical sciences can play in dealing with such challenges in the areas of Flood risk management, Water engineering, Coastal and waterway engineering, and Sustainable land management. In terms of modelling, we develop an integrated modelling framework to take into account the entire cascade of factors from the effect of climate change on storms and sea levels, to the physical and economic damages resulting from extreme events, allowing the robust determination of annual probability of damage states and a synthesized trade-off analysis of flood control pathways. This integrated, probabilistic analysis tool promotes the mission of EPSRC in modelling complexity using advanced mathematics and ICT.