Oasis evolution and human factors analysis in Hexi Corridor over the recent 20 years

The function of oasis in recent was continuously degraded because of disorder of land use and excessive development of water resources in the Hexi corridor.This research detailedly studied the change characteristics of the oasis from 1990 to 2010 through GIS and RS technology and quantitatively analyzed the man-made factors of the evolution of artificial oases using entropy weight method.The research shows that the artificial oases were constantly expanding in the past 20 years in the Hexi corridor because of human activity.The change intense of oases was the most from 2000 to 2005.From space change analysis,the change of oases were located in the middle and lower reaches of Hei river and Shiyang river was significantly higher than Dang river and Shule river.The increase of the artificial oases was mainly because of human exploitation of the nature oases and unused land.The evolution of modern artificial oases has closed relation with the human economic activities and the bearing capacity of the oasis in the Hexi corridor.