暴雨灾害 (Jun 2023)
Disaster-causing hazard assessment of rainstorms in Anhui Province
Abstract
Disaster-causing hazard assessment is the key to risk assessment and regionalization of rainstorms and flood disasters. Using the hourly and daily precipitation data of all national and regional meteorological stations in Anhui Province from the year of establishment of these stations to 2020, as well as the geographic information data, etc., this paper has determined the weights of the four characteristic quantities of the single station rainstorm process by the information entropy weighting method, and then calculated the rainstorm process intensity indexes and annual waterlogging indexes. The intensity grade of the rainstorm process is divided into four grades by using the percentage quantile method. According to the altitude and terrain changes, the hazard-inducing environment impact index and disaster-causing hazard index of torrential flood and plain waterlogging are calculated respectively, and the two are superimposed to obtain the comprehensive distribution of disaster-causing hazard of rainstorms in Anhui Province. The results show that the thresholds of the rainstorm process intensity index in Anhui Province based on the three percentiles of 50%, 75%, and 90% are 0.059, 0.095, and 0.154 respectively. The annual waterlogging index shows a spatial distribution of the "high in the south and low in the north" characteristic, with higher values in the Dabie Mountain, the central and western region along the Yangtze River, and the southwestern region of the Jiangnan, while relatively lower values in the Huaibei region and the middle of the Jiang-Huai region. The hazard-inducing environment impact indexes of torrential flood and plain waterlogging are closely related to terrain. The hazard-inducing environment impact index of the torrential flood is relatively high in the Dabie Mountain and southern mountainous area in Anhui Province, while the hazard-inducing environment impact index of plain waterlogging is relatively high in the northern part of Hefei, most areas along the Yangtze River and the eastern of Jiangnan. According to the risk evaluating principle of being subject to the higher one, the disaster-causing hazards of torrential flood and plain waterlogging have been superimposed and the comprehensive disaster-causing hazard map of rainstorms has been obtained. The high-risk area is mainly located in the southwest of Anhui, while the low-risk area is mainly located in the north of Huaibei, the middle and west of the Huaihe River, and the middle of the Jiang-Huai region. The evaluation results can be applied to the special work of comprehensive risk survey of meteorological disasters in the whole province, real-time meteorological disaster prevention and reduction service, climate feasibility demonstration of planning and major engineering construction, etc.
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