Impact of oasis water consumption on surface runoff of the Weigan River Basin based on NDVI

The relationship between oasis water consumption and surface runoff of the Weigan River Basin was analyzed by using NOAA/AVHRR NDVI remote sensing data collected from 1982 to 2006. The results showed that during the recent 25 years, both of oasis zone inflow and oasis water consumption were increased. The oasis water consumption was broke in 1995, which was delayed by 1 year compared to the break point of oasis inflow. Comparing with the beginning stage of the study, oasis NDVI and oasis area were increased by 94% and 73.7% respectively, both showed a continuous increased trends. From view of the relationship between oasis NDVI and surface runoff, oasis precipitation played an important role in oasis zone vegetation growth, while glacier runoff was regulating oasis inflow and maintaining stability of oasis. Changes in oasis area and basin surface runoff, the contributions of oasis precipitation, glacier runoff and precipitation runoff to oasis scale were 22%, 44% and 34%, respectively. However, from the assumption of scenarios of climate change and cryospheric change, the contribution of glacier runoff to oasis scale will be increased slowly in the future except under the scenario of the stable temperature; meanwhile the contribution of oasis precipitation to oasis scale will increase.