潮河流域降水-径流关系变化及驱动因子识别

基于1973-2010年长系列日降水、径流数据,利用降水径流双累积曲线、M-K统计检验和降水集中度等方法,结合HIMS模型模拟结果,分析了潮河流域降水-径流关系的变化及其原因。得到的主要结论如下：（1）近38年来,潮河流域降水变化较小,但径流下降趋势显著,降水-径流关系发生了两次突变,即在1973-1983年、1984-1998年和1999-2010年三个阶段降水-径流关系存在明显差异;（2）大雨日降水总和（P_≥20）与径流深关系较为密切,其变化是导致降水-径流关系在1983年发生突变的主要驱动因子;（3）HIMS模型模拟结果显示,1999-2010年潮河流域下垫面条件较前两阶段变化明显,人类活动引起的减水效应由第二阶段的14.93%增加至第三阶段的25.78%,人类活动是导致降水-径流关系在1998年发生突变的主要驱动因子。

Variation of rainfall-runoff relationship and the driving factors identification in the Chaohe River Basin

The Chaohe River basin, located in the northeast area of Beijing district, is a very important water source for the water supply of Beijing. Under the great impacts of both climate variability and human activities, the rainfall-runoff relationship in the Chaohe River Basin has undergone significant changes during the past 40 years, which threats to the water supply security of Beijing. By using the daily rainfall and runoff series data, we mainly investigated the variation of the rainfall-runoff relationship in the Chaohe River Basin during the 1973-2010, and found that the rainfall-runoff relationship can be divided into three stages. The driving factors causing the rainfall-runoff relationship changes in each stage were identified. Double mass curve of rainfall-runoff, indexes of concentration degree and concentration period, the Mann-Kendall (M-K) test methods, together with the HIMS (Hydro-Informatic Modelling System) model are used for this study. The results show that: (1) two change points were identified in the variation of the rainfall-runoff relationship in the Chaohe River Basin, and the change processes can be divided into three stages: 1973-1983, 1984-1998, 1999-2010. The mean annual runoff in each stage decreased more significantly compared with the mean annual precipitation, which make the rainfall-runoff relationship changed dramatically; (2) the sum of precipitation in rainstorm days and the runoff depth are closely related, which means that the change in the sum of precipitation in rainstorm days is the main driving factor for the obvious change of rainfall-runoff relationship in the 1983; (3) by analyzing the HIMS simulation results, we found that the underlying surface of the Chaohe River Basin during the 1999-2010 has changed significantly compared with the period of the 1973-1998, therefore human activity is the main driving factor for the obvious change of rainfall-runoff relationship in the 1998; the runoff-reducing effects caused by human activity in the Chaohe River Basin increased from 14.93% in the second stage to 25.78% after the 1998. As a result, under the impacts of both precipitation variations and continuous changes of subsurface, the runoff and water resources in the Chaohe River Basin would more likely decrease. The unfavorable situation would further cause the water resources shortage in the Beijing City. More effective and urgent measures should be implemented for water supply safety of Beijing.