毛乌素沙地土地沙漠化评价

基于遥感监测反演数据,以多等级土地沙漠化转化度为评价指标,研究构建了毛乌素沙地土地沙漠化转化度模型,并对20世纪80年代末到90年代末期间毛乌素土地沙漠化转化情况和转化机理进行了系统评价和分析。评价发现,毛乌素沙地土地沙漠化情况为:东部区沙漠化发展的转化度为12.113%,逆转的转化度为9.639%,所以该区沙漠化呈现加重的态势;中部区沙漠化发展的转化度为14.551%,逆转的转化度为18.954%,但强烈发展所占比例较大,可见该区土地沙漠化呈现面积缩小、程度加重的特点;西部区沙漠化发展的转化度为8.731%,逆转的转化度为7.298%,说明该区土地沙漠化发展略大于逆转,沙漠化面积扩大,但分析发现该区重度、极重度沙漠化土地逆转的转化度很高,总和为6.483%,约为发展转化度总和的两倍,所以该区土地沙漠化程度整体减轻。

Evaluation of desertification in Mu Us Sandy Land

By using remote sensing technology,monitor and inversion has been done in Mu Us Sandy Land for get-ring the information about state of desertification from the end of 1 980s to the end of 1 990s.In order to assess change grades,the desertification assessment model of Mu Us Sandy Land was constructed based on the multi-grade desertification changing index,the mechanism and state of desertification in Mu Us Sandy Land from the end of 1980s to the end of 1990s were systematically analyzed and assessed.In the study,Mu Us Sandy Land has been di-vided into three parts,i.e,the east part,central part and west part.The results could be showed as follows:First-ly,the desertification is aggravating in the east Mu Us Sandy Land,whose changing index is 12.11% in develop-ment and 9.64% in reverse.Secondly,the changing index is respectively 14.55% in development and 18.95%in reverse in the central part of the sandy land.but the evolution of desertification is severe.So the desertification proportion was reduced and desertification trend was severe in this part.Thirdly,the changing index of desertifica-tion is respectively 8.73%in development and 7.30%in reverse in the west part of Mu Us Sandy Land.The de-sertification proportion was increased.However,further analysis shows that the sum of changing index of severely desertificated area is 6.48% which is two times of that of severe desertification.Therefore,the desertification was alleviated in the west part in general.In this paper,desertification assessment model based on the multi-grade de-sertification changing indexes has been constructed innovatively,and the state of land desertification in Mu Us from the end of 1980s to the end of 1990s was expounded with the model.Results show the desertification situation of Mu Us Sandy Land,which can be used as supports for decision-making of the administration department combating desertification in Mu Us Sandy Land.Moreover,the results can provide the new thoughts for division patterns of land desertification eontrol in the north sandy areas in China.