Spatial and Tempor al Changes of Deser tification in the Headwater Ar ea of the Yellow River Using Remote Sensing
黄河源区土地沙漠化时空变化遥感分析

The objective of this paper is to detect desertification in the headwater area of the Yellow River with remote sensing. Firstly,the desertification classification scheme was established through field works and analysis on ancillary data of the headwater area of the Yellow River. Then,based on desertification detecting model,the spatial and temporal changes of desertification were detected in the headwater area of the Yellow River from 1986 to 2000 using Landsat TM/ETM images. The results revealed that the desertified land of the study area was about 3519.97 km2 in 2000,of which light desertified land was major portion. The result further showed that desertified land has increased and intensified seriously with an annual increasing rate of 21.8% from 1987 to 1996. During the 1990s,desertification has expanded and intensified,although the annual increasing rate is slower than that in the 1980s. Since the late 1980s,the desertification has kept intensifying in the headwater area of the Yellow River,although desertification has reversed in some regions. The headwater area of the Yellow River is one of the seriously desertified regions in the upper reach of the Yellow River and the Qinghai-Tibet Plateau. Therefore,it is urgent to combat desertification and protect eco-environment in the headwater area of the Yellow River.