Desertification Development and Its Cause in Oasis of Arid Areas -A Case Study of Turpan Oasis, Xinjiang

Based on high resolution remote sensing data-SPOT images of Turpan Oasis,by using of decision tree classification method,desertification information was abstracted and desertification evolution,development as well as conversion characteristics were analyzed in the paper.The results showed that wind erosion desertification and salinization were the main desertification types in research area.Moderate wind erosion desertification occupied the highest proportion,which accounted 64.05 % of the total in research area.Because of the reclamation of mild wind erosion desertification land,the total desertification land area decreased by 9.77% from 1986 to 2004.At the same time,part mild wind erosion desertification land converted to more serious desertification land.Severe desertification land and salinization land enlarged 2 and 12 times respectively.Speed of desertification reversal was higher than that of development,whereas the later period desertification development speed were accelerated,both showing that when desertification were harnessed,the desertification degree in part of the area was deepen.The development of desertification has brought enormous pressure on local environment.