The Temporal And Spatial Features Of Summer Rainfall And Flood Forecast Of Hubei Province Based On Risk Simulation Model

Hubei province is a place where meteorological disaster happens frequently and seriously in China,while flood disaster is always the most noteworthy disaster in Hubei.Frequent flood disaster and serious secondary disasters such as landslide,collapse and mud-rock flow directly endanger people's lives and property safety,affect the economic and social development.Summer(6~8 month)is when flood and waterlogging occurs most frequenly in Hubei province.The precipitation of the summer accounts for 35%~50% of the annual precipitation in most parts in Hubei,and extensive hard rain is the direct cause of the flood disaster.Based on the precipitation data of 16 meteorological stations in Hubei province,this paper analyzes the flood disaster,and forecasts the time when future flood disaster may happen in these areas.In order to study the flood disaster,we must determine the influence of the summer rainfall on the flood and waterlogging.This paper selects three indexes which are precipitation anomaly percentage,Z-index and moisture index,to represent the degree of the flood based on the precipitation in the typical areas of Hubei province in the summer of 1959~2015.The three indexes can be calculated based on the precipitation,in order to rank the degree of flood disaster both on the monthly scale and the seasonal scale.And then we can compare the result with the recordation in the meteorological yearbook,in order to find out which index is the most suitable one of Hubei province.Then we study the precipitation in summer of Hubei province using Monte-Carlo simulation,and find out the distribution of the 16 typical areas.According to the distribution of the 16 areas,the probability of each degree can be concluded using cumulative probability algorithm and inverse cumulative probability algorithm.At last,the flood prediction is made based on GM(1,1)model and regression model,in order to forecast the year when flood disaster may happen next time,and the results can also be verified when the year is 2016 or 2017.The main conclusions of this paper are as follows: Moisture index is the most sensitive index both on the monthly scale and the seasonal scale,so it is considered to be the most suitable index to reflect the degree of the flood disaster in Hubei province.According to the result of Monte-Carlo simulation,the summer precipitation in Fangxian,Yichang,Laifeng accord with the logistic distribution type;Zaoyang,Jingzhou,Yingshan,Huangshi accord with the lognormal distribution type,Enshi,Wufeng,Zhongxiang,Tianmen,Wuhan accord with the maximal distribution type,Badong,Laohekou,Macheng accord with the gamma distribution type,Jiayu accord with the triangular distribution type.Among these cities,the probability of Fangxian,Enshi,Zhongxiang,Wuhan when the flood disaster occurred in the summer was 34.14%,35.92%,32.57% and 31.57%.In most areas of Hubei Province,the summer precipitation and flood disaster had increased in the 1980 s and the 1990 s,but after 2000,there is a trend that the frequency of flood disaster may decrease.In the last part of this paper,the forecast of flood disaster which may happen during 2018~2020 is made,as well as the flood disaster warning graph.