Theory and methodology on monitoring and assessment of desertification by remote sensing

Desertification, which is affecting more and more of the world, has been a major problem throughout the past decades in the north of China. Desertification and its spatio-temporal evolution information are very important to confirm stratagem and measure of desertification and implement macromanagement effectively, which is helpful to promote environmental resources sustainable development. Remote sensing has been shown to be a powerful tool in monitoring and assessment desertification. This paper focuses on reviewing the theory and methodology of monitoring and assessment desertification by using high resolution remotely sensed data. On the basis of these theories and methods, the desertification in some counties at Hunshandake sandy desertification area was evaluated. The result indicates that quantitative monitoring and assessment of desertification in large area can be carried out by using high resolution remotely sensed image. It is vital to take reasonable estimation principle, establish scientific evaluation index and remotely sensed image interpreter symbol system, constitute feasible sand desertification classification project, and make use of appropriate interpreter means and technique routes. Compared with and the result from the low-resolution data, the evaluation to this method is more accurate, specific and valuable in application. The result of this method to evaluate regional desertification at Hunshandake desertification area indicates that, from 1970s, the acreage and proportion of the desertification at this area has augmented significantly, and the situation of sandy desertification is very serious.