Evaluation Method on Minqin Oasis Desertification with Remote Sensing

The paper studies the land desertification evaluation method by remote sensing techniques and its application on the Minqin Oasis desertification research. This includes the maximum likelihood decision rule and landscape pattern analysis based on the remote sensing spectrum, derived combination character and spatial structure characters. The experiment results showed that the method achieved satisfactory evaluation results since the overall accuracy of the desertification evaluation for Minqin county were over 0.8 in 3 different years. It will be the main method for desertification evaluation based on quantity remote sensing techniques in the future. From 1988 to 1997, the total desertification area of Minqin Oasis was not expanded. The change occurred between the desertification types and grades. During the period of 1988 to 1992, the water and wind erosion desertification process played the main role, the severity of regional desertification decreased, the reduced rate was 0.5%. From 1992 to 1997, the salinization erosion desertification process took the main role and land degradation increased, the deterioration rate was 1.4%. The water erosion process was less important in this region during the study period. The total landscape was most fragmentary and complex in 1997, by contrast, it was less fragmentary and more stable on the landscape structure in 1992. The landscape pattern index for each desertification class had changed differently. The landscape pattern change during the study period also indicated the different processes in the evoluation of land desertification in the study area.