| China is the region of high incidence flood disaster, the spatial assessment and trend prediction of flood disaster risk is very necessary. Heavy rainfall is a key factor to induce the flood. To predict the future climate change, temperature and precipitation will varying degrees of changes in different models, which increases the risk of uncertainty of the flood disaster in future climate scene. The definition of the flood disaster risk and the evaluation indexes and methods are in widely range of variations.This paper based on the disaster system theory and risk theory, considering the effect of rainfall, topography and river system as the flood occurrence factors, considering the characteristics of disaster factors and disaster bearing body, combining the maximum three daily rainfall in different return periods of and the terrain, landform, water system, water conservancy facilities and other factors to construct the flood disaster risk evaluation system. Combined with the hydrological frequency analysis and comprehensive weighting method, the establishment of flood disaster risk assessment model were build under climate change, to explore the space-time dynamic change of flood disaster risk under climate changes in base period and future period in china.Based on the summary of the relevant flood risk areas, combined with the trigger and effects of the flood, this study suggests that the flood disaster risk not only includes the n driver of atural environment, also includes the social feedback, which covers both the basic theory of risk framework and the disaster system theory. Combined with the driving factor and the feedback of flood, the paper put forward a flood disaster risk assessment model in different return period. The results show that, the index and model of risk assessment are practical..By means of Gamma and the combination of K-S and A-D testing method, making the comparison to the extreme precipitation over a long sequence of return period, the paper explored the distribution of different return period of maximum three daily rainfall value space,which is suitable to the country. With the Gamma function, the fitting method for long series precipitation data can get the different flood grade values response to different return period. The weighted method of evaluation index based on AHP and entropy method is more scientific. The results show that the annual maximum three daily rainfall in different return period showed a decrease from southeast to northwest in space distribution. The rainfall trend overall increase in the future, with a difference from east to west in China, the precipitation increase in west. The annual maximum three daily rainfall will increase significantly in parts of Eastern Xinjiang area, decrease in the upper reaches of the Yangtze River(Sichuan, Chongqing). In the future, southeast coast is still the high incidence area of strong rainfall weather.By exploring the spatial pattern change of flood disaster risk in China and the correlation of flood disaster risk patterns and social economic, the spatial distribution of flood risk in southeast is higher than northwest in China. Beijing. Tianjin and Tangshan area, Sichuan Basin and southern Guangxi Guangdong coastal area are areas in high risk of flood. In the future, flood disaster risk in different return period of is largely the same in spatial distribution as the base period, but the serious of flood disaster degree and the influence scope are different. Throughout the country, southeast is still a high incidence area.The evaluation results explored the spatial and temporal dynamic changes of flood disaster risk under future climate change in China from the macro level. Furthermore, corresponding countermeasures are proposed according to the different risk levels in different regions, the result provides a scientific basis for flood disaster risk management. |
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