基于数字滤波法的拒马河基流分割及演变规律研究

Baseflow separation and temporal changes in the Juma River,China

以大清河流域拒马河为研究对象,基于紫荆关水文站1950-2016年的日径流数据,采用改进退水常数后数字滤波法中的Chapman-Maxwell法,对拒马河径流过程进行基流分割,并对拒马河丰、平、枯年基流变化特征进行分析.结果表明:1)使用改进后退水常数(α=0.993)比以往经验所得退水常数(α=0.925)计算的基流量变化特征更稳定;2)基流与径流均呈减小突变,基流突变时间略早于径流突变时间,突变前后基流变化幅度小于径流变化幅度;3)丰、平、枯不同水平年基流对径流的贡献率分别达到35.80%、42.51%、52.20%,丰水年基流贡献率最小,枯水年基流是径流的主要补给源.研究结果可为保障河道生态基流及应对气候变化对河道生态系统的影响提供理论和技术支撑.

Digital filtering method with improved regression constant,the Chapman-Maxwell method,was used to separate baseflow from daily runoff in Zijinguan hydrological station in Juma River,China,with temporal trends of baseflow investigated.Modified receding water constant(α=0.993)calculated from Chapman-Maxwell method were found suitable to separate baseflow compared with experienced receding water constant(α=0.925).Annual runoff and baseflow presented decreasing trends with abrupt changes around 1967.Abrupt changes for annual baseflow were found to be earlier than for annual runoff.Changes in baseflow were found to make up to 35.8%,42.51%,and 52.20% of changes in runoff in flood,normal,and drought years.It is concluded that baseflow presents steady characteristics than changes in runoff,this plays a vital role in maintaining integrity of river ecosystem.