基于RS和GIS长城沿线沙漠化动态研究

基于遥感影像,以长城沿线榆林地区为研究对象,在野外实地观测和验证的基础上利用RS和GIS平台对该地区沙漠化进行动态变化研究。结果表明:在1988—2002年沙漠化面积在逐步减少;按照沙漠化的类型分析,在1999年之前,逆转区的面积为1 221 682.0 hm2,发展区的面积为1 285 603.0 hm2,发展区的面积大于逆转区的面积;1999年之后,发展区的面积为680 374.6 hm2,逆转区的面积为1 488 989.0 hm2,逆转区的面积远大于发展区的面积;从沙漠化程度分析,轻度和潜在沙漠化的面积在大幅度地降低,但中度以上的沙漠化面积仍然在蠕动扩展,这一数据表明榆林地区沙漠化的形势仍然不容乐观,要居安思危。

Study on Desertification Dynamics along the Great Wall by GIS And RS

The Yulin District, distributing along the Great Wall, is not only located in the agriculture-pasture transition zone, but also in the transition region between the desert and the loess plateau. There are many ecological environmental problems, anong with desertification is one of the nost serious. Based on the remote sensing images, DEM and the on-the-spot investigation data, the authors analyzed the desertification dynamics of this region by the technologies of GIS and RS. The results showed that before 1999 the desertification area was reducing, the reversed desertified land was 1 221 682.0 hm2 and the desertification developing area was 1 285 603.0 hm2; after 1999, the developing area was 680 374.6 hm2 and the reversing area was 1 488 989.0 hm2, showing obvious reversing trend. But the reversed desertification area are mainly from light and potential desertification land types, the moderate and severe desertification are still in developing status. So the desertification situation in the study region is hardly optimistic.