基于CMIP6的多情景上海雨洪风险时空格局评价及规划响应对策

Spatial-temporal Pattern Evaluation and Planning Solution of Urban Flood Risk in Shanghai Based on CMIP6

气候变化带来的雨洪灾害是城市发展的巨大挑战之一,评估城市未来的雨洪风险并开展有效的规划应对是目前城市发展的重大需求。未来气候情景下上海极端降水的时空格局还未得到充分研究。利用第六次耦合模式比较计划(CMIP6)中12个全球模式气候数据耦合上海市10个气象站点历史数据,选用Delta降尺度方法预测上海市SSP245、SSP585情景下的2025—2055和2070—2100年重现期为5、10、20、50、100年的降水。使用SCS-CN模型模拟得到了多情景下上海市径流深度,结果表明21世纪末期比21世纪中期最大径流深度最高增加100%。结合各区域排水能力,划分了上海市多情景下的雨洪风险等级。结果表明,上海市中心城区排涝标准较高,雨洪风险较低,而中心城区以外区域风险相对较高。针对不同风险等级区域,从流域视角统筹城市雨洪设施建设,合理布局,提出防洪、除涝、雨水排水相互协调的规划响应对策。

One of the major challenges for urban development brought by climate change is urban flooding caused by heavy rainfall.Evaluating future rainfall risks in cities and implementing effective planning and response measures is a critical need for urban development.Currently,there is not enough research on the spatiotemporal pattern of extreme precipitation in Shanghai under future climate scenarios.Using data from 12 global climate models in the Coupled Model Intercomparison Project Phase 6(CMIP6)and historical data from 10 meteorological stations in Shanghai,the Delta downscaling method was employed to predict precipitation with a return period of 5,10,20,50,and 100 years under the SSP245 and SSP585 scenarios for the periods of 2025-2055 and 2070-2100.The SCS-CN model was used to simulate the runoff depth in different scenarios,and the results indicate that the maximum runoff depth at the end of the 21th century is 100%higher than that in the middle of the 21th century.Based on the drainage capacity of different regions,rain-flood risk levels were divided in Shanghai under different scenarios.The results show that the central urban area of Shanghai has a higher drainage standard and lower rain-flood risk,while the risk in other areas outside the central urban area is relatively higher.In response to different risk levels,a watershed perspective was used to coordinate the construction and layout of urban rain-flood facilities,and response measures were proposed to coordinate flood control,drainage,and rainwater drainage.