精细时空尺度珠江三角洲城市化对洪水响应机制及未来洪水风险预估

Due to fast and booming urbanization, city is becoming the major habitat for human activities. Hence, rainstorm-induced urban flooding and related losses of property and mortality have aroused increasing human concerns, and which make it significant the investigation of urban responses to rainstorm-induced floods, related mechanisms and evaluations of urban flooding risks. However, the standing researches focused limited influencing factors and processes with respect to urbanization and floods and also limited researches was done on urban flooding at finer spatial and temporal scales. In this case, this current project was proposed to analyze urban responses to rainstorm-induced floods with respect to timing, processing and principles at finer temporal and spatial scales using statistical techniques and hydrological modelling methods taking the urbanized areas within the Pearl River Delta region as case studies. Fractional contribution of spatio-temporal variations of rainstorms and urbanization to floods will be quantified by taking specific river basins with different urbanization degrees or intensities as case studies. Besides, urbanization expanding models will be accepted to model spatial patterns of urbanized areas under different urbanization scenarios, which together with weather prediction models and related predicted weather results will be used to model urbanization responses to rainstorm-induced floods at finer spatio-temporal scales. Finally, risk evaluation will be done for urbanized areas under different urbanization scenarios, weather predictions. This project will be of great scientific and theoretical merits in terms of development of human knowledge in hydrological effects of urbanization, human mitigation to urbanization under different climate changes and also is potential to provide theoretical and scientific grounds for management of urbanization and urbanization related floods and other natural hazards in a changing environment.

快速城市化使城市成为人类最主要的栖息地，而城市暴雨洪水及其灾害损失也受到越来越多的关注，开展城市化对暴雨洪水响应机制及洪水风险评估意义重大。但已有研究考虑的因子及过程较为单一，且时空精细化研究程度不足。本项目以中国重要城市化区域珠三角为研究区，选取城市化程度不同的典型流域，采用数理统计、水文模型等方法，探究精细时空尺度上城市化对暴雨洪水响应时间及洪水过程与规律，模拟并比较不同城市化过程下洪水特征差异性，量化暴雨时空变化和城市化对洪水变化的贡献；采用城市扩张预测模型预测低、中和高速3种不同扩张情景下未来城市化空间模式，结合数值天气预测，精细模拟暴雨时空过程对城市扩张的响应；结合未来不同气候变化、城市扩张及其对暴雨过程响应，预估未来城市化洪水风险及其时空分布。该项目对于理解城市化水文效应、城市洪灾的综合防、减灾具有重要理论与实际意义，也为城市化及其管理提供重要科技支撑。

项目负责人在项目执行期内致力于洪涝灾害监测与模拟领域、以及气候灾害防灾减灾，以中国重要城市化区域珠三角为主要研究区，建立了翔实的数据资料库，研发了区域乃至全球的降水和气温高精度数据集。通过多数据融合和数理统计方法，首先探究了气候变化背景下中国极端降水的历史和未来不同排放情景的趋势变化，阐明了城市化对短时间尺度降水及气温时空差异性的影响，剖析了城市化进程对珠三角城市化增温和小时降水的响应规律，量化城市化对城区气象因子变化的影响。接着研究了珠江流域现在和过去1000年间洪水频率变化，并研究城市化发展下的土地利用变化对流域洪峰流量的影响，发现珠江中下游流域洪水风险增强。我们进一步剖析了珠江三角洲地区暴雨事件驱动因子，基于土地利用发展模型构建未来城市化格局，并预估了珠江地区未来洪涝灾害风险，得到了未来珠江三角洲地区洪涝灾害风险指数空间分布格局，为珠三角地区应对洪涝灾害和政府应对气候变化提供了科学依据，并对地区洪涝灾害防灾减灾具有重要意义。此外，我们将研究范围扩展全球，对全球河流流量变化进行了归因分析，探讨了人为增温和区域发展不平衡对全球洪水风险的影响，对理解全球气候变化和人类活动对水文水资源的影响具有重要意义。项目负责人由于在自然灾害防灾减灾领域的杰出贡献，2019年被评为“北京市应急管理领域学科带头人”，在项目的资助下，共发表论文33篇，其中第一标注8篇，SCI Q1区论文23篇。