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黄土高原水蚀风蚀交错区生态环境脆弱,河川基流量的多少及其变化对维持该区生态系统健康具有重要意义。利用黄土高原水蚀风蚀交错区窟野河流域多年实测径流资料,研究国内外常用的滑动最小值法、HYSEP法和数字滤波法3类共8种自动基流分割方法在该研究区的适用性。结果表明:1)8种方法所得年均基流指数差异较大,最大为0.651 5,最小为0.330 5,而滤波法中的F2(Chapman-Maxwell法)和F4(Eckhardt法)法估算的结果最为稳定可靠,均值分别为0.386 8和0.330 5,标准差分别为0.042 8和0.046 1;2)F2和F4法分割的基流过程线与实际更吻合,2种方法估算的年基流量与实际观测值的验证效果最好,Nash-Sutcliffe效率系数分别为0.691和0.718,平均相对误差分别为9.83%和5.05%,F2和F4法估算的基流结果均能客观稳定地反映该研究区的基流状况,适合于该研究区进行基流分析;3)从F2和F4 2种方法估算值的平均值来看,窟野河流域基流量近50年来呈现减少趋势,其减少量占总径流减少量的41%。
The ecological environment in the ecotone between water erosion and wind erosion in the Loess Plateau is fragile. The quantity and change of the base flow of the river are of great significance to maintain the ecosystem health of this area. Based on the multi-year measured runoff data in the Kuye River Basin in the cross-section of water-erosion and wind erosion in the Loess Plateau, the applicability of 8 automatic base flow segmentation methods, including sliding minimum method, HYSEP method and digital filtering method, is studied in this study area. The results showed that: 1) The average annual baseflow index of the eight methods varied greatly, with a maximum of 0.651 5 and a minimum of 0.330 5. The results of the Fp (Chapman-Maxwell method) and F4 (Eckhardt method) The most stable and reliable, with mean values of 0.386 8 and 0.330 5 respectively, with standard deviations of 0.042 8 and 0.046 1, respectively. 2) The base flow process curves segmented by F2 and F4 are more in line with the actual ones. The validation results are the best. The Nash-Sutcliffe efficiency coefficients are 0.691 and 0.718, respectively. The average relative errors are 9.83% and 5.05%, respectively. The base-flow results estimated by F2 and F4 methods all reflect the base of the study area objectively and stably 3) Based on the average of the estimated values of F2 and F4, the basic flow in the Kuye River Basin showed a decreasing trend in the past 50 years, and the decrease of the total runoff decreased 41% of the amount.