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本文以白洋淀流域为研究对象,首先应用Mann-Kendall非参数检验法分析流域内8个典型水文站点近50年的年径流变化趋势。在此基础上采用Hurst指数法分析年径流变化趋势在未来的可持续性。利用Pettitt突变检测法分析各水文站点年径流发生突变的年份,比较突变前和突变后年平均径流量的变化情况。选取流域内和附近6个气象站点1957年-2006年近50年间的年平均气温和年降水量资料,对比其在突变年份前后的变化情况,分析气象要素对流域径流量的可能影响。研究结果表明:白洋淀流域各站点年径流量呈下降趋势且具有较强的持续性,且流域上游年径流下降趋势更为显著,而流域下游年径流下降值β高于上游;1979年是白洋淀流域年径流发生突变的年份,且突变后时段内平均年径流量显著低于突变前时段;对突变前后时期径流变化率的分析表明,沙河水系年径流变化可能主要受气候变化变化影响,而拒马河水系径流变化可能受人类活动影响主导;流域在突变年份以后气温整体升高约1℃,降水量约降低56.6mm,气象因子可能是径流不断减少的重要原因。
In this paper, the Baiyangdian River Basin is taken as the research object. Firstly, Mann-Kendall nonparametric test is used to analyze the annual runoff change trend of eight typical hydrological stations in the past 50 years. On this basis, the Hurst index method is used to analyze the future sustainability of the trend of annual runoff. Using the Pettitt mutation detection method, we analyzed the years of annual runoff changes at hydrological stations, and compared the changes of annual mean runoff before and after mutation. The annual average temperature and annual precipitation data of 6 meteorological stations in and near the basin during the past 50 years from 1957 to 2006 are selected to compare the changes before and after the abrupt year and to analyze the possible influence of meteorological elements on runoff. The results show that the annual runoff at all sites in Baiyangdian Lake basin shows a decreasing trend and has a strong persistence. The annual runoff declines more significantly in the upper reaches of the basin, while the annual runoff declines β in the lower reaches of the basin are higher than in the upper reaches. In 1979, Annual runoff occurred in the year of mutation, and the mean annual runoff in the post-mutation period was significantly lower than that in the pre-mutation period. Analysis of the rate of runoff change before and after the mutation showed that annual runoff change in Shahe River water system may be mainly affected by climate change, The change of runoff in river system may be dominated by human activities. After the year of change, the temperature in the basin increased by about 1 ℃ and the precipitation decreased by 56.6 mm. The meteorological factors may be the important reasons for the decreasing of runoff.