Dynamic analysis of desertification land in the typical source regions of sandstorm in Xinjiang

Based on the remote sensing data and NDVI,we calculated the desertification degree and analyzed the characteristics of its historical evolution from 1990 to 2005.The results showed that:(1)The oasis desertification degree became severity from 1990 to 2000.(2)The oasis desertification degree was better than before from 1990 to 2000.(3)Although the desertification degree was better than before in recent five years,other styles of desertification were on the increase besides heavy desertification from 1990 to 2005.That will be the potential thread to become the heavy desertification.This paper also showed that the main natural influencing factors on oasis land desertification are precipitation and evaporation.The population growth and land and water resources exploitation are the main humanity influencing factors.