西藏沙漠化程度及其分区评价

从区域沙漠化程度概念出发,本文依据西藏沙漠化普查和荒漠化监测所得的1991年与1997年两期土地沙漠化数据,选择沙漠化土地占地率、重度沙漠化土地占地率、沙漠化土地年增率、沙漠化土地年扩大面积占地率四个指标,采用多指标加权综合指数法,对西藏各个沙漠化县(市、区)的沙漠化现状程度等级进行了定性与定量兼有的评价,在此基础上对西藏沙漠化程度进行了区域概括与分区。评价结果,西藏65个沙漠化县(市、区)中有16个属于中度沙漠化程度,其余全部属于轻度,全区可划分出9个沙漠化程度区,其中轻度区4个、中度区5个,总体而言西藏土地沙漠化程度较轻。

Evaluation on the Sandy Desertification Degree and its Regionalization in Xizang Autonomic Region

Based on the investigation date of sandy desertification and monitoring of desertification in Tibet(Xizang Autonomous Region) in 1991and 1997,the ratio of the sandy desertified land area,the ratio of severe desertified land,the annual increasing ratio of sandy desertified land and the ratio of annual increasing sandy desertified land were chosen as the evaluation criteria,to quantitatively and qualitatively evalue the status degree of sandy desertification of every county influenced by sandy desertification in Xizang Autonomous Region by use of the comprehensive index evaluation method,and the regions with different degrees of sandy desertification in Xizang Autonomous Region were given.The evaluation results showed that there are 49 slight degree counties and 16 middle degree counties in 65 counties influenced by sandy desertification in Tibet,which are divided into 4 slight degree regions and 5 middle regions of sandy desertification.As a results,it could be concluded the sandy desertification degree in Tibet is slight,which is not the same as the research results given before.