Monitoring land desertification in the source region of the Yangtze River Qinghai Province by remote sensing technology

The land desertification is one of the major environmental problems in the Source Region of the Yangtze River, Qinghai Province. With the Three Gorges Dam construction, more and more attention is paid to restoring the degraded eco-environment of the region. In this study, the sandy land was classified into three types, and the desertified land was also inventoried correspondingly into three levels. Through interpreting TM images in 1986 and 2000, the databases of sandy land at two times had been established, respectively. And then the desertified land data was derived through overlaying the databases of sandy land. The result shows that there is 1,459,365 ha of sandy land in the region in 2000, accounting for 9.89% of all study area. There is 11,877 ha of newly sandy land resulted from land desertification, and sandy land has increased by 7.35% during about 14 years in the end of the 20th century.