Desertification is one of the major ecological and environmental problems of Jiuquan city. Understanding the status of local desertification land and analyzing its dynamic evolution characteristics is a key prerequisite for maintaining regional ecological security and ensuring sustainable economic and social development. Based on RS and GIS technology with the latest satellite image data,field investigation and human-computer interaction inter-pretation method,this paper monitored the area, type and degree of desertification land in Jiuquan city. Further-more,the dynamic characteristics and reasons of desertification land in Jiuquan city were analyzed by comparing the current monitoring data with the data obtained in 2009. The results showed that the currently existing sandy land ar-ea of Jiuquan city was 9.563 4 million hm2. Compared with 2009, the desertification land area decreased by 40 700 hm2,showing an overall downward trend with the annual change rate of -0.08%;The desertification degree is mainly regarded as severely and extremely severely,showing a overall downward trend. The area of severe deser-tification land decreased by 78 700 hm2with the annual change rate of -0.75%,the area of extremely severe de-sertification land decreased by 19.47 million hm2with the annual change rate of -0.64%.The desertification land type was dominated by mobile sandy land(dune),semi-fixed sandy land(dune),fixed sandy land(dune) and Gobi,all of these land type is 98.16% of the land area of desertification. It concluded that the increase of precipi-tation and surface runoff, the implementation of ecological engineering, the intensive use of water resources, the development of the project for closing wells and pressuring farmland, and the construction of infrastructure were main reasons for reducing desertification land area in Jiuquan city.%[目的] 沙漠化是酒泉市面临的主要生态环境问题之一,了解土地沙漠化现状,分析其动态演变特征,是维持区域生态安全,保证经济社会可持续发展的关键前提.[方法] 研究依托GIS技术,结合最新卫星影像数据,采用野外调查和人机交互解译的方法,对酒泉市沙漠化土地面积、类型、程度进行了监测,同时通过对比酒泉市上期 (2009年) 沙漠化土地监测数据,分析了沙漠化土地的动态特征和变化原因. [结果] 酒泉市现有沙漠化土地面积956.34万 hm2,较2009年减少了4.07万 hm2,年变化率-0.08%,呈整体减少趋势;沙漠化程度以重度和极重度为主,但整体呈减轻趋势,具体表现为重度沙漠化土地面积减少7.87万 hm2,年变化率 -0.75%,极重度沙漠化土地面积减少19.47万 hm2,年变化率-0.64%.沙漠化土地类型以流动沙地 (丘)、半固定沙地 (丘)、固定沙地 (丘) 和戈壁为主,占沙漠化土地面积的98.16%.[结论] 降水和地表径流的增加、生态工程的实施、水资源利用集约化、关井压田工程的开展以及基础设施建设是酒泉市沙漠化土地面积减少的主要原因.
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