基于GIS的四川省冻融侵蚀界定与评价

根据作者和前人相关成果，提出四川省冻融侵蚀区界定的理论依据，并以GIS技术为支撑，确定出了四川省冻融侵蚀区的范围。接着在综合分析冻融侵蚀的影响因子的基础上，提出了适合四川省的冻融侵蚀相对分级标准；利用此标准，在GIS软件支持下实现了四川省冻融侵蚀相对分级。运用分级结果对四川省冻融侵蚀进行了综合评价。

Identification and Evaluation of Freeze-thaw Erosion in Sichuan Province on the Basis of GIS

Freeze-thaw erosion is the third largest type of soil erosion,second only to water erosion and wind erosion.However,due to many restrictions,little research on freeze-thaw erosion has been done both in China and other countries.Especially lacking is the definition of freeze-thaw erosion zones and the assessment methods of freeze-thaw erosion.This paper has three objectives.First based on the analysis of existing relevant research result and taken Sichuan province as study area,a theoretical basis for the defining freeze-thaw erosion zones has been put forward,a formula for calculating the altitude of the lower bound of the freeze-thaw erosion zone has been established,then,the freeze-thaw erosion zones in Sichuan province has been identified by using GIS,Secondly,based on the comprehensive analysis of impact factors of free-thaw erosion,this paper chooses three indexes(i.e. annul temperature range,slop and vegetation),works out the criteria for relative classification of freeze-thaw erosion,and realizes the relative classification of the freeze-thaw erosion in Sichuan province under the support of GIS.Finally, synthetic assessment of freeze-thaw erosion in Tibet has been done according to the relative classification result.The results show that freeze-thaw erosion in Sichuan Province has the following regular:1)freeze-thaw erosion lies mainly in the west in Sichuan province,such as:Shiju,Dege,Baiyu,Gezi,Seda,Xinlong,Batang,Rangtang,Aba,and Daocheng;2)in the aspect of the degree of freeze-thaw erosion,the main grade of freeze-thaw erosion is light degree,and it takes up 37.22% of freeze-thaw erosion zones;3)spatial distribution of different grade of freeze-thaw erosion are much different,which shown by uniform distribution of slight degree and light degree,and by centralism distribution of other grades.