为发现时间与空间上阿拉善左旗沙漠化土地的变化趋势,选取2009年、2013年、2017年的MODIS影像数据作为数据源,在ENVI和ArcGIS软件的支持下,对阿拉善左旗的沙漠化土地空间分布进行了分析与研究。结果 表明:(1)在2009—2017年期间土地整体向良好方向发展,在研究时间内沙漠化程度一直以严重沙漠化和重度沙漠化为主要沙漠化形式,二者占全部沙漠化土地面积比例的95%以上,重度沙漠化所占比例最大,高达60%以上。(2)2009—2017年期间沙漠化土地主要是以严重沙漠化向重度沙漠化转化,重度沙漠化向中度沙漠化转化,中度沙漠化向轻度沙漠化转化的方式呈现,直至2017年轻度沙漠化与中度沙漠化的面积也相对应的有所增加。(3)严重沙漠化土地重心在2009—2013年期间向北偏移了0.08°,整体向东北方向偏移了24.53 km,2013—2017年往北偏移0.08°,整体向西北方向折回偏移了25.46 km,严重沙漠化迁移变化最为明显呈退减趋势。沙漠化土地重心由北向南依次是严重沙漠化、重度沙漠化、中度沙漠化、轻度沙漠化。在沙漠化的治理与防治过程中,应当采取因地制宜,合理利用土地以有效地治理沙漠化。
In order to find out the change trend of desertification land in time and space in Alxa Left Banner, MODIS image data from 2009, 2013 and 2017 were selected as data sources. With the support of ENVI and ArcGIS software, the spatial distribution of desertification land in Alxa Zuoqi was analyzed and researched. The results showed that:(1)during 2009—2017, the land as a whole developed in a good direction; during the study period, the degree of desertification had been mainly deserted and severely desertification, which accounted for more than 95% of the total desertification land area; the proportion of severe desertification was the largest, and reached up to 60%;(2)during the period from 2009 to 2017, desertification lands were mainly transformed from severe desertification to severe desertification, severe desertification to moderate desertification, and moderate desertification to mild desertification; until 2017, the areas of desertification and moderate desertification also increased correspondingly;(3)the center of gravity of severe desertification land shifted 0.08° northward from 2009 to 2013, shifted 24.53 km northeast overall, shifted 0.08° northward from 2013 to 2017, and turned back to the northwest as a whole; after 25.46 km, the change of severe desertification was most obvious. From north to south, the center of gravity of desertification land was severe desertification, severe desertification, moderate desertification, and mild desertification. In the process of desertification control and prevention, the measures should be adopted to effectively control desertification according to local conditions and rationally use land.
