黄河流域降雨-径流关系时空演变研究

由于气候变化和人类活动的影响,黄河流域的降雨-径流关系发生了显著性变化,严重影响流域水资源的规划和管理。为了揭示黄河流域降雨-径流关系的变化特征、趋势及主要驱动因素,研究采用Mann-Kendall检验、双累积曲线法、Copula函数、累积量斜率变化率法分析1960-2010年黄河流域的径流系数时空变化规律、7个主要区间降雨-径流关系的突变年份、降雨径流组合概率变化,以及气候变化和人类活动对降雨-径流关系变化的贡献率。结果表明:黄河全流域降雨-径流关系有明显的趋势性变化,其中除黄河源区的径流系数没有明显变化及少数地区的径流系数有增大的趋势外,绝大部分地区的径流系数有明显减小的趋势;黄河流域7个主要区间,即唐乃亥以上、唐乃亥—兰州、兰州—头道拐、头道拐—龙门、龙门—三门峡、三门峡—花园口及花园口—利津的降雨-径流关系突变年份依次为1989、1984、1997、1979、1992、1987和1970年,年份差异主要受到人类活动时间的影响,流域内大规模水土保持措施开展的年份、水利工程的兴建时间都是造成降雨-径流关系发生转折的重要因素;黄河流域主要区间降雨-径流关系发生转折后,同等降雨条件下其产流能力降低;人类活动是降雨-径流关系变化的主要驱动因素,贡献率均在50%以上,且越往下游,影响越大。

Spatio temporal evolution of the rainfall-runoff relationship in the Yellow River Basin

Due to the impact of climate change and human activities, the rainfall-runoff relationship in the Yellow River Basin has undergone significant changes, seriously affecting the planning and management of water resources in the basin. In order to reveal the change characteristics, trends and main driving factors of the rainfall-runoff relationship in the Yellow River Basin, we adopted Mann-Kendall test, double accumulation curve method, Copula function and slope change ratio of cumulative quantity (CSRCQ) method to analyze the spatio temporal variation of runoff coefficient, years with abrupt changes of rainfall-runoff relationship in seven main regions, probability change of rainfall-runoff combination, and the contribution rate of climate change and human activities to the relationship in the Yellow River Basin during 1960-2010. Results show that the changes of the rainfall-runoff relationship in the whole basin showed obvious trend characteristics, among which the runoff coefficient in most areas showed a downward trend, except that the source area of the Yellow River showed no obvious change and a few areas had a tendency to increase. The abrupt change years of the seven main regions of above Tangnaihai, Tangnaihai-Lanzhou, Lanzhou-Toudaoguai, Toudaoguai-Longmen, Longmen-Sanmenxia, Sanmenxia-Huayuankou and Huayuankou-Lijin were 1989, 1984, 1997, 1979, 1992, 1987 and 1970 respectively. The time difference of the abrupt changes was mainly affected by the time of human activities. Moreover, the year when large scale soil and water conservation measures were carried out in the basin and the time when water conservancy projects were constructed were all important factors that caused the turning point of the relationship between rainfall and runoff. After the abrupt change of the rainfall-runoff relationship in the main regions of the Yellow River Basin, the runoff generation capacity under the same rainfall conditions decreased. Human activities were the main driving factors for changes of the relationship between rainfall and runoff, with a contribution rate of more than 50%, and the further downstream, the greater the impact.