以陕某宁青四省区1996年和2000年的TM影像为信息源,在全数字方式下运用遥感技术和地理信息系统技术结合建立了两期沙地数据库.通过分析得出:2000年四省区有沙地面积7910807hm^2与1996年相比净增加6424hm^2,沙地占全区总土地面积的比例由5.733%增加到5.737%,平均每年净增加0.001%,不同省区沙地面积的变化情况是:陕西净增加0.004%,甘肃净减少0.017%,宁夏净减少0.479%,青海净增加0.051%,同时结合实际情况,分析了不同地区沙地变化的驱动因子.

By using digital method of remote sensing and geographical information system techniques, TM images of 1996 and 2000 have been interpreted to establish the database of sandy land of two periods in Shaaxi, Gansu, Ningxia and Qinghai Provinces. Through the study practice and analyzing of sandy land databases,the following points can be concluded:In the study area there is as much as 7,910,807hm 2 sandy land in 2000 and more 6,424hm 2 than in 1996. The percentage of sandy land area over the whole area change from 5 733% in 1996 to 5 737% in 2000, and increases 0 004% in 4 years. In different regions, the change of sandy land is various, such as, it increased 0 004% in Shaanxi Province, decreased 0 017% in Gansu Province, decreased 0 479% in Ningxia Region and increased 0 051% in Qinghai Province. And then based on the change types of sandy land, the factors affecting sandy land changes were analyzed according to the situation of different regions.