Prediction Of Urban Flood Risk In China Under The Background Of Global Warming

With the intensification of global warming,extreme precipitation events have occurred more frequently,and urban flood disasters have emerged one after another,which has caused serious impacts on people's production and life.Therefore,it is necessary to estimate the urban flood conditions under the background of global warming and propose related recommendations to provide scientific support for urban municipal planning.This paper uses the "Urban Flood Prevention Standards" data developed by the Ministry of Housing and Urban-Rural Development to measure the surface drainage capacity of our cities,and the daily precipitation data of meteorological stations and the GFDL-CM4 precipitation model data of Coupled Model Intercomparison Project Phase 6(CMIP6)to predict the future urban flood risk under SSP585 and SSP245 scenarios.On this basis,further attribution of the temporal and spatial distribution characteristics of urban flood in my country in the 21 st century are analyzed.In addition,the Pearson-? probability distribution model,the Gumbel probability distribution model and the exponential probability distribution model are used to calculate the probability of the city's annual maximum daily rainfall to formulate ideal Urban Flood Prevention Standards.The main conclusions are as follows:(1)The Urban Flood Prevention Standards formulated by the Ministry of Housing and Urban-Rural Development can be used as a scientific indicator to measure urban drainage capacity.Moreover,the Urban Flood Prevention Standards presents the spatial distribution characteristics of decreasing from the eastern and southeast coastal areas to the northwest inland,and the Urban Flood Prevention Standards of high-grade cities is higher than that of low-grade cities.(2)Under the SSP245 and SSP585 scenarios,the extreme precipitation events,the frequency of future flood,and the intensity of flood of cities in China will have significant abrupt changes around 2055.Therefore,2055 can be used as the dividing line to analyze urban flood in 2021-2055(early 21 st century)and 2066-2100(late 21 st century)periods.(3)Under the SSP245 scenario,the urban flood frequent areas,areas with high flood intensity,and areas with high urban flood risk levels are spatially concentrated in North China,northern Shandong Peninsula,middle and lower reaches of the Yangtze River,and southern Yunnan.In terms of time,the areas with frequent urban flood,areas with high flood intensity and urban flood risk levels in the late 21 st century are significantly higher than those in the early 21 st century.(4)Under the SSP585 scenario,the areas with frequent urban flood,areas with high flood intensity,and areas with high urban flood risk levels are spatially concentrated in North China,northern Shandong Peninsula,middle and lower reaches of the Yangtze River,southern Yunnan and central.The difference is that the Middle East of Gansu Province has also become a high risk area of flood.In terms of time,the characteristics of frequent urban flood areas,high flood intensity areas and urban flood risk levels in the late 21 st century are significantly higher than those in the early21 st century.(5)The spatial and temporal distribution characteristics of SSP245 are similar to SSP585.The urban flood frequent areas,areas with high flood intensity and areas with high urban flood risk are mainly distributed in North China,northern Shandong Peninsula,parts of the middle and lower reaches of the Yangtze River,southern Yunnan Province and parts of central and Eastern Gansu Province.In terms of time,it is higher in the late 21 st century than in the early 21 st century.However,under the SSP585 scenario,the frequency of urban flood,the intensity of flood,and the risk level of flood from 2021-2055 and 2066-2100 are significantly higher than those of the SSP245 scenario.Future development scenarios driven by fossil fuel combustion will face greater flood prevention challenges.(6)In the 21 st century,extreme precipitation events increased in China,resulting in more frequent urban flood disasters,higher flood intensity and flood risk in China.In order to reduce the possibility of urban flood disasters,the urban flood prevention and control standards in North China,northern Shandong Peninsula,parts of the middle and lower reaches of the Yangtze River,southern Yunnan,and Longnan of Gansu Province should be promptly improved in the late 21 st century.