Risk Assessment And Regionalization Of Drought Disaster In Gansu Province

With the development of the first national natural disaster risk survey,the research on natural disasters has stepped into a new trend.Dry early disaster is one of the most serious disasters in the world.Its duration,economic loss and impact range are the first of all kinds of natural disasters.In the case of global warming,the frequency of drought disasters is higher and higher,and the destructive power is greater and greater.Gansu Province is located in the northwest of China,the topography is more complex,most of the region is in the desert and Gobi desert,less rainfall,so the frequency of drought in Gansu Province is still very high.Based on the theoretical basis of natural disaster risk assessment,this paper uses the annual precipitation data,social attribute data and geographic information data of Gansu Province from 1962 to 2020,and uses GIS technology to select 13 corresponding evaluation indicators from the four impact indicators of drought disaster risk factors,disaster pregnant environment sensitivity,disaster bearing body loss susceptibility and disaster prevention and mitigation capacity Finally,combined with the principle of natural disaster risk zoning,the risk zoning of drought disaster in Gansu Province is carried out,and the results are verified by the drought affected area from 2000 to 2019.The main contents and conclusions are as follows:(1)Based on the annual precipitation data and temperature data collected,the frequency of light drought,medium drought,heavy drought and special drought in Gansu Province is selected as the index factor for risk assessment of disaster factors by using standardized precipitation index and drought data.For the evaluation of the sensitivity of pregnant environment,the precipitation level percentage,vegetation coverage and field water holding capacity are selected as the index factors for the risk assessment of disaster causing factors To study the factors of assessment;for the loss of disaster bearing bodies,the economic density,the proportion of cultivated land area,the average livestock and population density are selected for evaluation and research;the fiscal revenue and the area affected by drought and flood are selected as the evaluation indicators for disaster prevention and mitigation capacity.(2)Based on the analysis of the four factors influencing the risk of drought disaster in Gansu Province,the following conclusions are drawn:the risk assessment of the disaster causing factors in Gansu Province shows that the southern region of Gansu Province is mostly in the sub high risk area;most of the middle and north areas are in the lower risk areas,and the north is in the lower risk areas Some areas are in the sub low risk area and medium risk area;the sensitivity of pregnant environment decreases from north to South;most of Jiuquan city is in high sensitive area,Gannan area and Linxia Prefecture are in medium sensitive area;Longnan area,Tianshui City and Pingliang City are in the low sensitive area;Dingding Most of the western regions are distributed in the sub low,medium and sub high areas.(3)The study on the assessment of the disaster bearing body loss shows that the regional loss in the eastern part of Gansu Province is relatively large.Gannan and Linzhou are in low and low loss areas.Dunhuang,Guazhou and Jinta are in the middle loss area;Yumen City is in the sub high and easy loss area;Jiayuguan is in the sub high and easy loss area;Zhangye City,most of the areas are distributed in the middle vulnerable areas;most areas of Baiyin City and Lanzhou city are distributed in the sub high vulnerable areas;in Longnan area,Wudu district is in high vulnerability area;Wenxian is in the sub low loss area;min The county and Xihe county are in the middle loss area,and the ability of disaster prevention and mitigation is gradually enhanced from north to south.Jiuquan city is located in the low disaster prevention and mitigation area except Dunhuang City,Jiayuguan is in the middle disaster prevention and mitigation area,most of the areas in Wuwei are in the middle disaster prevention and mitigation area;Baiyin City and Lanzhou city are distributed in the sub high disaster prevention and mitigation area;Longnan area is in the area of medium disaster prevention and mitigation capacity.(4)Through the comprehensive evaluation and analysis of four influencing factors and the regionalization of Gansu Province,the following conclusions are drawn:Gansu Province high risk areas are mainly concentrated in the Loess Plateau area of Longzhong;the sub high risk areas are located in the east of Gansu Province;the desert areas north of Hexi Corridor,Gannan plateau and Longnan are in the medium risk areas;the west corridor is located in the middle risk areas The area is in the sub low risk zone,and most of Qilian mountain area is in the low risk area.The results of the division are basically consistent with the drought disaster area in 2000-2019 and other scholars' relevant research.