Comprehensive Evaluation On Vulnerability Of Disaster Bearing Bodies Of Social-ecological System In Qinghai Tibet Plateau

How to reduce the vulnerability of disaster bearing bodies is a hot and cutting-edge issue of scientific concern for sustainability in the international community.The Qinghai Tibet Plateau is the region with the greatest influence of global climate change and the tectonic activity.Due to its strong vulnerability to external disturbances,and the unique geographical environment is conducive to the development of natural disasters,disaster risks increase continually with social and economic development,making it one of the regions with the most types of natural disasters in China.Thus,it is of great strategic and practical significance to study the vulnerability of hazard bearing bodies in this region for the sustainable development of plateau society and economy.In this paper,the statistical data and spatial raster data are first applied to establish the vulnerability database of hazard bearing bodies of social and ecological system in Qinghai Tibet Plateau,and then based on VSD(Vulnerability Scoping Diagram)model framework,26 indexes and 15 factors were selected from the database,including population density,added value density of primary industry,total power density of agricultural machinery,number of beds of medical and health institutions per 10000 population,different types of value coefficient of ecosystem,annual average climate erosivity index and resilience coefficient of different vegetation types,an evaluation index system of vulnerability of hazard bearing bodies in this area from three dimensions respectively: exposure degree,sensitivity and disaster-response capacity(resilience)are constructed.The multi-objective linear weighted function is also used to measure the social and ecological vulnerability quantitatively.On this basis,the comprehensive vulnerability of hazard bearing body is integrated.Finally,the coefficient of variation method,variable slope method are used to analyze the characteristics of spatiotemporal evolution of social vulnerability in each county from 2000 to 2017,and predict its change trend.By using Arc GIS spatial analysis methods,such as local spatial autocorrelation analysis,Getis-Ord Gi* hotspot detection and trend surface analysis,this paper discusses the spatial distribution characteristics and influence mechanism of vulnerability of hazard bearing bodies within this area,and proposes purposefully countermeasures for disaster reduction,hoping to provide scientific and technological support for disaster prevention and reduction in this area,the achievements are as follows:(1)The vulnerability distribution of hazard bearing bodies in Qinghai Tibet Plateau is generally the trend of high in the southwest and low in the northeast.The extremely and highly comprehensive vulnerable area is mainly located in Hehuang Valley,Gonghe Basin,Lhasa area,central part of Qiangtang Plateau,Himalaya Mountains and hinterland of Hengduan Mountains;the distribution area of extremely and highly social vulnerability is mainly located in Hehuang Valley,hinterland of Hengduan Mountains,Lhasa area,Qiangtang Plateau;The distribution area of extremely and highly ecological vulnerability is mainly located in the central and western parts of Southern Qinghai Plateau,the central part of Qiangtang Plateau and the middle and lower reaches of the Yarlung Zangbo River.(2)The results of Lisa and hotspot detection show that the comprehensive vulnerable area of the Qinghai Tibet Plateau presents the shape of “multi-core”,including four high vulnerable hotspot core areas of Hehuang Valley,hinterland of Hengduan Mountains,Lhasa area and central Qiangtang Plateau,and three low vulnerable coldspot core areas of Southern Qinghai Plateau,middle and lower reaches of Yarlung Zangbo River and the periphery of Tarim Basin;the social vulnerable area presents the shape of “single core”,distributed in Hehuang Valley;the ecological vulnerable area presents the “scattered” shape in the some parts of Southern Qinghai Plateau and Qiangtang Plateau.(3)In the aspect of vulnerability model of social-ecological system,Qiangtang plateau presents “high-high” model,Lhasa area presents “high-medium high” model,among which Hehuang Valley,Gonghe County,Guinan County and Quxu County are“social-vulnerability-oriented counties”;Zhidoi County and Lhari County are“ecological-vulnerability-oriented counties”.Lhasa area and some counties in the central part of Qiangtang Plateau are overlapping area of social-ecological vulnerability,which are the most vulnerable area on the plateau.Damxung County,Nyemo County,Doilungdeqen County,Lhunzhub County,Langkazi County and Lhozhag County in Lhasa area are the “highly exposure-medium low sensitivity-low disaster-response capacity(resilience)area”,which are the most vulnerable area on the plateau,and will be the key prevention area in the future.(4)The evaluation results of vulnerability subsystem demonstrate that:The extremely and highly comprehensive exposure area is mainly located in Hehuang Valley,West Sichuan Plateau,Lhasa area,middle and lower reaches of Yarlung Zangbo River,and Yunnan part of Qinghai Tibet Plateau,among which Lushui City,Fugong County,Weixi Lisu Autonomous County in Yunnan Province are highly social-ecological exposure overlapping area,which are extremely exposure area on the plateau;the extremely and highly social exposure area is mainly located in Hehuang Valley,Gonghe Basin,eastern edge of West Sichuan Plateau,Lhasa area.The extremely and highly ecological exposure area is mainly located in Hehuang Valley,Gannan Plateau,West Sichuan Plateau,Yunnan part of Qinghai Tibet Plateau and Big Bend Region of Yarlung Zangbo River.The extremely and highly comprehensive sensitivity area is mainly located in the central and western part of Southern Qinghai Plateau,the periphery of Qaidam Basin,Kunlun Mountain,the periphery of Qiangtang Plateau and Gangdise Shan,among which Zhidoi County,Zadoi County,Qumarleb County and Madoi County are the overlapping area of social-ecological sensitivity,and the severe sensitive area on the plateau;the extremely and highly social sensitive area is mainly located in Southern Qinghai Plateau,the area from eastern part of Qaidam Basin to Qilian Mountains,Northwest Sichuan,Big Bend Region of Yarlung Zangbo River;the extremely and highly ecological sensitive area is mainly located in the central and western parts of Southern Qinghai Plateau,the periphery of Qaidam Basin and Gangdise Shan.The slight and low comprehensive disaster-response capacity(resilience)area is mainly located in the area from Qiangtang Plateau to the northern slope of Himalaya Mountains,in which the Qiangtang Plateau and Madoi County in Southern Qinghai Plateau are overlapping area of low disaster-response capacity-resilience,and are extremely low disaster-response capacity-resilience area on the plateau;the slight and low disaster-response capacity area is mainly located in Qiangtang Plateau,South Tibet Valley,hinterland of Hengduan Mountains and Himalaya Mountains;the slight and low resilience area is mainly located in the Southern Qinghai Plateau and the central and western of Qiangtang Plateau.(5)In terms of spatiotemporal evolution of social vulnerability: From 2000 to2017,the overall social vulnerability of hazard bearing bodies in Qinghai Tibet Plateau gradually decreased from north to South;the mean value of social vulnerability()of hazard bearing bodies in Qinghai Tibet Plateau decreased from0.388 to 0.289,showing a trend of positive development;the spatial difference of vulnerability decreased year by year during this period,but it increased after 2012;the vulnerability of counties around Xining City,Lhasa City and Changdu County decreased rapidly.By 2017,the majority of the plateau has become the low vulnerable area.Dege County,Yushu City,Nagqu County and Namling County belong to the vulnerable area with low-exposure,which will be the most vulnerable area.The future vulnerability will increase in the areas located in western part of the Qiangtang Plateau,Hehuang Valley,Southern Qinghai Plateau and Gonghe Basin,of which the vulnerability in Southern Qinghai Plateau and the western part of the Qiangtang Plateau will increase significantly,which are the key prevention area.