Impacts of climate change on the runoff and estimation on the future climatic trends in the headwater regions of the Yellow River

Sensibility of the runoff to climate change in the headwater regions of Yellow River was analyzed based on the measured data from the hydrological and weather stations in the regionsfrom 1961 to 2009.On the basis of high correlation between runoff and climatic factors,a prediction model of the runoff was established,and in terms of future climate scenarios provided by means of the down-scaling climate model,the runoff under medium emission scenarios were predicted.The results indicated that variations of temperatures in the regions had been oscillating with arising trend in the 49a,evaporation increased significantly and annual precipitation showed no apparent trend change,but had the obvious interannual and interdecadal oscillations.There was a remarkable linear correlativity between runoff and precipitation and temperature in the regions.The runoff has decreased continually because of the temperature rising resulting runoff evaporation loss more than precipitation recharge role.But in recent years the precipitation increased to bounce back.Results showed that the mean runoff will decrease 14.9%and 24.7% in the 2020s and 2050s compared with the baseline specified from 1961 to 1990.Therefore,damages of the effects of climate change on runoff in the headwater regions of the Yellow River generally outweigh the potential benefits,but with large uncertainty in the predictions.