长江河口三角洲风暴洪水危险性情景模拟与关键影响因素定量识别

Estuarine delta, functioning as a complex socioecological system and witnessing the drastic exchange of energy and substances within the interface of rivers, oceans and inlands, is quite sensitive and prone to the increasing risk of natural disasters in the face of climate change and unprecedented urbanization. This research project focuses on the Yangtze Estuarine Delta and simulation of storm surge flooding that has been a major threat to safety and sustainable development of this very important area of economy, technology, and people’s wellbeing of China. The research will contribute to the body of knowledge by conducting in-depth analyses of the influence of various key factors on storm surge flooding, including both direct factors such as the intensity and tracks of typhoons and indirect factors such as the offshore terrain, land subsidence and see level rise. The storm surge model will be calibrated using the historical data of typical typhoons. Then, setting the year 2010 as a baseline, the calibrated model will be used to simulate the storm surge flooding under multiple compound scenarios projected to year 2030 and 2050 based on predicted climate change, sea level rise, land subsidence, and human induced land cover changes by literature documentation and remote sensing data. Moreover, a separated evaluation model is considered to statistically measure the influence of each factor and identify the key factor(s) of the risk of storm surge flooding. In addition to explicitly revealing the influencing mechanism of diverse environmental factors from a theoretical perspective, the application outcome of this proposed project is to serve as useful reference for strategic plans and a decision making tool to mitigate the risk of storm surge flooding by municipality.

在气候变化和快速城市化背景下，河口三角洲地区所面临的极端灾害风险日益增大。本研究立足长江河口三角洲这一海、河、陆交互作用敏感区域，在对影响该区域风暴洪水的直接因素（台风路径与强度等）和间接因素（近岸海床地形演变、陆域与海塘沉降、海平面上升等）特征进行深入分析基础上，以2010年为基准年份，2030和2050年为目标年份，科学构建风暴洪水复合灾害情景；在高精度海陆地形数据和水动力模型支持下，开展风暴洪水危险性复合情景模拟；运用分离评判法等统计学方法对造成风暴洪水危险性的关键因素进行定量测度。本研究不但在河口三角洲地区多因素影响下，风暴洪水形成机制研究方面具有重要科学意义，而且在针对关键影响因素，积极防范极端风暴洪水方面具有现实指导意义。

在气候变化和快速城市化背景下，河口三角洲地区所面临的极端灾害风险日益增大。本研究立足长江河口三角洲这一海、河、陆交互作用敏感区域，在对影响该区域风暴洪水的直接因素（台风路径与强度等）和间接因素（近岸海床地形演变、陆域与海塘沉降、海平面上升等）特征进行深入分析基础上，以2010年为基准年份，2030和2050年为目标年份，开展了风暴洪水危险性复合情景模拟，并对造成风暴洪水危险性的关键因素进行了定量测度。具体研究进展和关键认识为：（1）建立了长江河口三角洲可能最大风暴潮（Probable Maximum Storm Surge, PMSS）情景构建方法体系，开展了PMSS危险性情景模拟、风险评估与风险区划，最终从工程策略和非工程策略两个方面建立了研究区PMSS风险防范的策略体系，研究成果对研究区防范极端风暴洪水具有重要指导意义。（2）首次建立了风暴洪水关键影响因素贡献率定量估算的方法体系，并以长江河口三角洲作为实证研究区，以2030和2050年为目标年份，测算了地面沉降、河口沖淤演变和海平面上升3个间接因素对风暴洪水影响的贡献率，研究成果对于精确开展河口三角洲风暴洪水风险研究具有重要的科学指导意义。