According to statistics, the shortest duration (3, 6, and 12 hours) of precipitation in Fujian was caused by the typhoon. The coastal areas were dominated by typhoon and rain. From July to October, it was typhoon and rain, and the inland areas were dominated by frontal rainstorms. However, the short-term heavy rainfall that induced local flash floods was concentrated in April-October, and the April-June was the heavy rain in the southern part of China. Heavy rain can occur throughout the year. Fujian is located on the southeast coast of China and is a typical subtropical monsoon climate zone. The southeastern coast of China is affected by severe typhoon disasters. The largest number of deaths and direct economic losses is caused by storms and floods. on the data of China’s meteorological disasters from 2004 to 2013 show that storm floods and drought disasters are the most important meteorological disasters in China. In storms, floods (mountain floods) in the mountainous gullies in the mountains are the main disasters caused by natural disasters in China and have become the focus and difficulty in flood prevention and mitigation in China.
The frequency and intensity of extreme flood events in typical flood-risk areas in the south have generally increased. pointed out that under the background of increasing climate change and human activities, floods and floods are still one of the serious natural disasters in China in the future. In the future, China will face more severe climate risk challenges. The high-risk area of tropical cyclone disasters is located in the northern part of the South China Sea and the eastern part of the Philippine Sea. However, in the past 10 years, the frequency and intensity of tropical cyclones in typhoons and above have increased significantly. The frequency and average intensity of tropical cyclones in the surrounding seas of China have shown a weak downward trend in the past 60 years. Since the 21st century, the intensity of tropical cyclones landed in China has increased significantly. found that the average number of high-temperature days in China increased by 28.4% from 1961 to 2015, and the number of rainy days increased by 8.2%. Floods, mudslides and landslides occur frequently in hilly areas, causing casualties, property damage and infrastructure damage, and ecological and environmental damage. It is affected by many factors such as special natural geographical environment, extreme severe weather and economic and social activities. In order to prevent and reduce the flood disasters accurately and effectively, the flood risk forecast and the disaster-caused facts should be considered at the same time.Ĭhina is a mountainous country, and the hilly area covers about two-thirds of the country’s land area. It showed the tourism development would cause the river way blocking and increase the risk of flood. For example, Meranti caused serious damage to trees, increased river blockages, resulting in changes in flood inundation time and depth, affecting the flood process. The reason was that in addition to the differences between the surface rainfall forecast and the real situation, many actual situations cannot be ignored. The post-mountain simulation assessment also showed that the flood inundation range basically matched with reality, but the flood process was biased. The simulated flood scenarios and the field trip’s results were basically matched in upstream and not matched in the downstream.
#Dis purity torrent torrent#
The highest mountain torrent disaster was forecasted by the refine precipitation based on the disaster-caused critical rainfall of the Mayang Stream. The result shows that the cause of Mayang Stream’s mountain torrent disaster of the typhoon Meranti is the heavy rainfall and the strong wind. After the process of typhoon, the mountain torrent caused by Meranti was back analyzed by using the decided flood area model, then compared with the results of filed investigation to verify the accuracy of the disaster-caused critical precipitation forecast and the effect of monitoring and early warning services. Then based on the flood risk warning service system of small and middle rivers of Fujian Province, the risk warning service of mountain torrent disaster is developed during the impact time of Meranti in 2016. The result is used as the mountain torrent disaster monitoring and warning indicators and risk assessment of the Mayang Stream.
Based on the flood area hydrodynamic model, this paper backs the analysis of the risk warning point of the Mayang Stream in the typical flood process, to determine the disaster-caused critical precipitation and the corresponding flood risk map at different depths of submergence.
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