Contributions of Climate Variability and Human Activities to the Variation of Runoff in the Wei River Basin, China

Abstract:

The Wei River Basin is a typical arid and semi-arid area of the Yellow River Basin. The heuristic segmentation method was used to detect the inflection points of the annual runoff. The slope change ratio of accumulative quantity (SCRAQ) method was applied to computing the relative contribution of human activities and climate changes to the decreasing runoff in the whole basin and the basin above Linjiacun. For the whole basin, when 1960-1969 is selected as the baseline, the contributions of climate changes and human activities in 1970-1993 are 26.47% and 73.53%, respectively, those in 1993-2005 are 23.33% and 76.67%, respectively. When 1970-1993 is selected as the baseline, the contribution of climate and human impacts in 1994-2005 are 18.88% and 81.12%, respectively. The results imply that human activities are the dominant driving factors on runoff reduction, whose effect is increasingly intensifying. Furthermore, in order to verify the contribution of human activities and climate changes based on the SCRAQ method, a method based on the Budyko hypothesis was used in this paper. The results indicate that the contribution of human activities and climate change based on the SCRAQ method is consistent with that based on the sensitivity-based method.