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.