干旱半干旱地区土地利用／覆被变化研究——以民勤绿洲为例

以西北内陆干旱半干旱地区民勤绿洲为例，利用1992年、1999年和2006年三期TM影像资料，分析民勤绿洲15年来土地利用／覆被变化情况，包括土地利用／覆被数量变化的幅度、速度以及土地利用／覆被空间变化的主要类型，土地利用／覆被重心迁移的方向．结果表明：绿洲的面积先增加后又减少，但总量是增加的；绿洲的耕地面积一直呈增加趋势；草地面积在1999年急剧增加，增加的草地主要由沙地转化而来，后又急剧减少到1992年的水平；在空间分布上，绿洲有从下游向上游迁移的趋势，绿洲下游质量明显恶化．

Land Use/Cover Change Research in Minqin Oasis During the Last 15 Years

Take Minqin oasis for example,based on three TM images in 1992,1999 and 2006,the author researches the oasis land-use changes, analyzes Minqin oasis land-use/cover changes during the last 15 years, including the extent and speed of changes in land-use quantity, the main types of land-use spatial changes, and the migration direction of center of gravity in land use/cover. The results showed that： the area of the oasis increased firstly and then decreased, but the total area is increasing; the area of oasis has been an increasing trend, and the area of meadow increased dramatically in 1999, the added area mainly were ever sand,later reduced to the same quantity as that of 1992;As to the spatial distribution, the spatial distribution of oasis has a tendency from downstream to upstream migration, there are obvious deterioration in the quality of the lower reaches of the oasis. So,we must establish a scientific and rational institution of land and water resources usage and the balance development mode of middle and lower reaches of water resource, ensuring that the Minqin oasis ecological environment improved.