气候和人类活动对黄河源区径流量变化的贡献率研究

根据1961-2015年黄河源区有关台站的观测数据，利用差积分法、累积距平法对黄河源区径流量和气候变化趋势进行了分析，并基于累计量斜率变化率分析方法评估气候和人类活动对黄河源区径流量减少的贡献率。结果表明：黄河源区年径流量、年降水量、年平均最大冻土深度呈减少趋势，源区蒸散量呈增大趋势；与基准时期1961-1989年相比，在不考虑气温影响的情况下，气候和人类活动对黄河源区径流量变化的贡献率在1990-2008年分别为33.12%和66.88%，在2009-2015年分别为73.61%和26.39%；两个时段相比，气候对径流量减少的贡献率上升，而人类活动的贡献率下降，这与气候变暖及2005年黄河源区启动的三江源自然保护区生态保护和建设工程有关。

The contribution rate of climate and human activities on runoff change in the source regions of Yellow River

In order to better understand the contribution rates of climate and human activities to the runoff yield in the source regions of Yellow River, using linear trend method, correlation analysis, stepwise regression method, differential integral method and cumulative distance method, the meteorological data and hydrologic data in the source regions of Yellow River from 1961 to 2015 had been analyzed. It was obtained that the mean flow has showed a decreasing trend in the recent 55 years in the source region of Yellow River, for example, the annual runoff has decreased by 24.8 m³·s^-1·(10a)^-1. For climate reason, precipitation in main flow area has decreased by 7.5 mm·(10a)^-1 and in the major flood period it has decreased by 6.8 mm·(10a)^-1. Moreover, influenced by temperature rising, evaporation has increased with the rate of 4.9 mm·(10a)^-1. In addition, if the temperature effect can be ignored, assessing the influence of climate and human activities to runoff in the source regions of the river has found that:compared with the period from 1961 to 1989, the effect of climate and human activities accounted for 33.12% and 66.88% from 1990 to 2008; and for 73.61% and 26.39% from 2009 to 2015, respectively. Compared the two periods, the contribution rate of climate to the variation in runoff has risen to 73.61% from 33.12% in the period from 2009 to 2015 and play a leading role. However, the contribution rate of human activities to the variation in runoff decreased from 66.88% to 26.39% which is mainly attributed to the glacial ablation, permafrost degradation, surface water infiltration increasing and other effects of recent global warming. Meanwhile, the launching of the ecological protection and construction project of Sanjiangyuan national nature reserve have a significant positive impact.