近30a龙羊峡水库周边地区沙漠化遥感监测

Remote Sensing Investigation of Aeolian Desertification in Longyangxia Reservoir Region in Recent 30Years

在RS和GIS支持下,选取4期遥感数据,采用室内解译和野外检验修正的方法,获得龙羊峡水库周边地区不同时期土地沙漠化数据库。结果显示,在过去30a中,龙羊峡水库周边地区土地的沙漠化在时间上经历了一般发展到正在逆转两个阶段;2000年以后,极重度沙漠化土地和重度沙漠化土地变化最为明显,均呈现逆转趋势,其中极重度沙漠化逆转为其他类型的总面积为145.90km2,重度沙漠化土地逆转为中度沙漠化面积为146.44km2;在沙漠化土地的空间分布上,过去30a里,沙漠化土地主要集中分布在龙羊峡两岸的塔拉滩和木格滩地区;研究区内沙漠化的逆转主要是由重度和极重度沙漠化土地转变为中度和轻度沙漠化土地。1975—1989年,研究区的降水呈增加趋势,但是由于这一时期人为因素的影响,沙漠化呈不断加剧的态势;1989—2000年,研究区的气候趋向于暖干化,加上过度放牧等人为因素,重度和极重度沙漠化土地持续发展;2000年以后,研究区的气候趋向于暖湿化,政府实施了一系列生态环境保护、恢复计划,沙化土地呈现逆转的态势。

In this paper,satellite images interpretation and GIS analysis were used to obtain the data of aeolian desertification land in Longyangxia reservoir region in 1975,1989,2000 and 2005.The results showed that the variation of total area of aeolian desertification land experienced two stages from slowly development to preliminary reversal in the past 30 years;some severe desertification and extremely severe desertification had been reversed since 2000;The aeolian desertification land was mainly distributed in the Talatan and Mugetan;Reversal was mainly from severe and extremely severe aeolian desertification lands to moderate and slight aeolian desertification lands.Though the precipitation in the study region increased from 1975 to 1989,the aeolian desertification land grew because of the impact of human factors.From 1989 to 2000,because of the climate condition of warming and drying and overgrazing,severe and extremely severe aeolian desertification lands developed continually;After 2000,the present situation of aeolian desertification had been reversed because the climate condition tended to warn and wet and the government took a series of ecological environment protection and rehabilitation measures.