Drought Risk Assessment Study Based On Different Scales

As the core content of disaster risk management,disaster risk assessment is the crucial basic research with which human society can prevent natural disasters,control and lower the natural disaster risk.As the significant part of disaster risk assessment,drought risk assessment covers a large scope ranging from county,city,province,region,even a nation to town,village,GaZha or fanning and grazing household.Global warming and increasing human activity have both contributed to the higher risk of drought,and drought risk assessment makes us aware of the essential causes of drought,which plays a significant role to improve the decision-making ability of governments at all levels concerning disaster prevention and risk reduction process.The study of drought risk assessment has undergone a development process from single scale to Multi-scale,with remarkable scale effect of evaluation indicators,data sources,data accuracy,evaluation significance and instructive significance of evaluation results.And only Multi-scale evaluations can reflect the nature of drought risk.This article collects and processes relevant data,while drawing lessons from Chinese and overseas drought risk research results,analyzing the theories and methods of drought risk assessment.After dividing China's administrative regions into large scale and small-scale areas,this article defines large scale area by using banner and city as risk unit,and defines small scale area by using GaZha as risk unit.Then it uses10 counties and cities in Xilingol as the large scale research area,and71 GaZha in Abaga Banner as the small scale research area and finally gets the following results:(1)From the results of drought risk assessment in large scale regions,we know that Sonid Right Banner and Xianghuang Banner are the high-risk areas of drought;Zhengxiangbai Banner and Zhenglan Banner are the second high-risk areas of drought;Abaga Banner,East Ujimqin Banner and Sonid Left Banner are the medium-risk areas of drought;Erenhot City and Xilinhot City are the second low-risk areas of drought;Xiwuzhumuqin Banner is the low-risk area of drought.(2)From the results of drought risk assessment in small scale regions,we can see that there are 13 GaZha at the high-risk areas of drought,accounting for 18% of the total numbers of GaZha in Abaga Banner,mainly distributed in the south and north of Abaga Banner;there are 11 GaZha at the second high-risk areas of drought,accounting for 15% of the total numbers of GaZha in Abaga Banner,mainly distributed in the small areas in northeast,northwest and southeast;there are 19 GaZha at the medium-risk areas of drought,accounting for 27% of the total numbers of GaZha in Abaga Banner,mainly distributed along the west boundary of Abaga Banner;there are19 GaZha at the second low-risk areas of drought,accounting for 27%of the total numbers of GaZha in Abaga Banner,mainly distributed in the center of Abaga Banner;there are 10 GaZha at the second low-risk areas of drought,accounting for 14% of the total numbers of GaZha in Abaga Banner,mainly distributed respectively in the center of Abaga Banner and small areas of the south.(3)Different scales of drought risk assessment,selection of evaluation index and data accuracy have remarkable scale effects benefits.The research on multi-scale can enrich the theory and method of drought risk assessment,highlight the uniqueness of drought risk assessment in pastoral area,and provide the basis of disaster prevention and reduction for administrative division policy so as to deal with drought risk more comprehensively.Comparison and analysis of two scales of drought risk assessment and application studytells us that,in terms of index selection,climate,topography and other natural factors will exact strong influence on large-scale drought risk assessment,but when it comes to analyzing small-scale basis,regional differences can be hardly noticed because of the week influences.The selection of socioeconomic indicators in small-scale areas is more specific,which can reflect the each GaZha's attitude in the face of the risk,its economic situation and equipment conditions.While the selection of social indicators in large scale areas is more general,which can only reflect the overall situation of each banner and city.Regarding the data accuracy,the natural data on the large scale can obtain strong and high precision,but poor accessibility of social data with low precision.while small scale data was obtained by collecting information about each herdsman in Abaga Banner,in this case,the data features fine space size and high precision.