Abstract
The purpose of this study is to clarify the characteristics of desertification areas and to understand how desertification has progressed over the last 10-20 years in some model areas of diffrent types of desertification using Landsat data.
1) Desertification in eastern China was characterized by reactivation of fixed sand dunes at Naiman, surface erosion of the topsoil at Lanxi, and severe gully erosion resulting in badlands at Yuanmou.
2) Three indices were developed to extract desertified area using Landsat data. Vegetation Index for extracting non-vegetated area ; (TM4 —TM 3)/(TM4+TM 3) Structure Index for excluding man-made structure ; (TM5—TM 1)/(TM5 + TM 1) Soil Color Index for extracting specific soil area ; (TM 3 —TM 1)/(TM3 + TM 1) These equations were applied to three areas we studied. And yearly changes of desertified areas were obtained through superimposing those areas of different years.
3) No significant changes in areal extent of desertification were seen in any of the analyzed regions of Naiman, Lanxi, and Yuanmou. Land management around major settlements, roads, railway lines, etc., in all these regions was relatively meticulous and desert land was being reclaimed. However, in outlying regions new desert land was appearing, making it difficult to say that suitable land management was being practiced.
4) We evaluated the processes of desertification in Yuanmou Province, where gully erosion is prominent.
