Quantitative contribution of climate change and human activities to runoff changes in the Wei River basin, China

摘要

Surface runoff from the Wei River basin, the largest tributary of the YellowRiver in China, has dramatically decreased over last 51 years from 1958 to2008. Climate change and human activities have been identified as the twomain reasons for the decrease in runoff. The study period is split into twosub-periods (1958–1989 and 1990–2008) using the Mann–Kendall jump test.This study develops an improved climate elasticity method based on theoriginal climate elasticity method, and conducts a quantitative assessment ofthe impact of climate change and human activities on the runoff decrease inthe Wei River basin. The results from the original climate elasticity methodshow that climatic impacts contribute37–40% to the decreasein runoff, while human impacts contribute 60–63%. In contrast,the results from the improved climate elasticity method yield a climaticcontribution to runoff decrease of 22–29% and a humancontribution of 71–78%. A discussion of the simulationreliability and uncertainty concludes that the improved climate elasticitymethod has a better mechanism and can provide more reasonable results.