Using the TM Image for Monitoring Land Desertification

Desertification is land degradation characterized by wind erosion mainly resulted from the excessive human activities in arid, semiarid and part of sub humid regions in the North China. It is effective that using the TM image for monitoring land desertification. In this paper, the author discusses: ①the methodology of monitor desertified land using remote sensing data, ②some influencing factors on the monitoring results, ③the TM image characteristics the index system of the desertified land. Based on above work, an indicator system of desertification had been established. This system uses the changes of surface features as the main indicators and also considers the changes of soil, vegetation and ecosystem etc. These indicators have widespread representation and are easy to identify. A practice of monitoring and assessing the land desertification had been carried out in the Mu Us Region, Northern China, which had brought out the development and state of land desertification in different periods in the region. The desertified land area in the Mu Us Region had decreased 1 936 km\+2 (from 32 586 km\+2 in 1987 to 30 650 km\+2 in 1993). That means during this period the process of desertification was in the situation of reversion, and there were 277 km\+2 desertified land had been controlled annually. Based on such methodology, much more work could be conducted on the development, distribution and disastrous processes of desertification in North China using remote sensing and GIS techniques, making desertification research enter quantitative analytical and economic assessment stage.