Research On Spatio-temporal Changes Of Flood Disaster Risk In Ankang City Based On Cloud Model

Flood disaster is a destructive natural disaster.Around the world in a variety of natural disasters,damages caused by the flood disasters accounted for the largest proportion.China is one of the counties which have frequent flood disaster with the most serious losses.Ankang City in Shaanxi Province,is one of the cities that the economy development relatively fast and flood disaster hit frequently in history.Since the Western Han Dynasty,flood disasters occurred in Ankang City have been 181 times that occured once average 12 years and caused severe damages basically.The frequency of flood disaster featured fluctuations in an upward trend.Especially in modern times,the flood disaster frequency increased significantly,resulting in more serious losses,seriously affecting the healthy development of the economy and people’s lives.This highlight the importance of risk assessment of flood disaster in Ankang City.Flood disaster risk assessment is the precondition and foundation to scientifically undertake flood protection and disaster reduction.Therefore,this paper takes Ankang City as a study area to analyze the spatial and temporal variation of flood disaster risk by using the cloud model.First of all,the paper analyzes the change characteristics of flood disasters in Ankang City in terms of time,space,periodicity and losses based on historical statistics.Then analyzes the spatial and temporal variation of flood disaster risk of Ankang City in 1983,1998,2003,2005 and 2010 by constructing a assessment model based on the cloud model from the perspective of Ankang City’s physical geographical characteristics and social economic development to select assessment indexes.Finally,this paper analyzes the causes of flood-prone in Ankang City.This paper gets some conclusions as follows:(1)Statistics and analysis of flood disasters in Ankang City showed that the frequency of flood disaster increased in the time scale,the space distribution of flood disaster was different,the flood disaster had significant periodic,and damages caused by flood disasters were serious.These demonstrate that the flood disaster risk of Ankang City is serious and highlight the necessity for risk assessment of flood disaster.(2)The model of flood disaster risk assessment is constructed based on cloud model to analyze the spatial and temporal variation of Ankang City by selecting precipitation,etc to establish the indexes system of flood disaster risk assessment from the four aspects of disaster-causing factor,disaster-pregnant environment,supporting body,disaster prevention and reduction ability,which according to the natural geographic features and social economic development of Ankang City.(3)The flood disaster analysis of 1983,1998,2003,2005 and 2010 in Ankang City showed that in the time scale,except for Hanbin District,Shiquan,Pingli,Xunyang and Baihe County whose risk levels didn’t change,other counties changed in different levels.The risk levels of Hanyin and Ningshan County increased,Langao and Zhen Ping County first decreased and then increased,and Ziyang County first increased and then decreased.The whole risk levels were increased.On the spatial scale,risks along the Hanjiang River in Ankang City were higher than other areas.Specifically,high risk areas increased,higher risk areas first increased and then decreased,medium risk areas decreased,lower risk areas increased,and low risk areas decreased.(3)This paper analyzes the reasons of the flood disaster that frequently occurred in Ankang City from two aspects about natural and social factors,concluding that the main reasons are the particular climate environment,the unique natural and geographical characteristics and the influence of human activities on the environment.This paper introduces the cloud model to analyze the temporal-spatial variation of flood disaster risk,which has a good reference value,fills the blank of temporal-spatial analysis of flood disaster risk in Ankang City and provides a new idea and method for flood disaster risk assessment.The study results are available for all counties and districts in strengthening early warning of flood disaster,timely adjusting flood control and disaster mitigation planning,minimizing flood disaster losses,promoting healthy and stable development of economy and society.