基于VIC模型的黑河上游流域径流模拟不确定性分析

Uncertainty analysis of VIC model based on GLUE method

研究采用VIC(variable infiltration capacity)模型对黑河上游流域地区的水循环过程进行模拟,并应用GLUE(generalized likelihood uncertainty estimation)不确定性分析方法定量探讨模型参数的敏感性和输出的不确定性.研究结果表明,VIC模型率定期和验证期的Nash效率系数分别为0.62和0.64,流量过程线拟合较好;所选需测定的VIC模型的7个参数中,最大基流量Dmax、下层土壤最大含水量的比例系数Ws以及第一层土壤含水层厚度d13个参数对模型敏感,其中参数d1最为敏感;除部分低流量区外,实测流量基本在置信度90%下模型预报的不确定性范围内.研究结果表明,VIC模型能够较好地模拟黑河上游流域的径流变化过程,具有较好的适应性.

Heihe River basin is the second largest inland basin in Northwest China.The increasingly serious water problem and eco-environmental problems have attracted widespread attention.In this study the VIC (Variable Infiltration Capacity)model was selected to simulate the hydrological cycle for the upstream areas of the Heihe River basin.GLUE (Generalized Likelihood Uncertainty Estimation)uncertainty analysis method was used to investigate the sensitivity of model parameters and the uncertainty of model outputs.The results showed that the Nash-Suttcliffe coefficient of efficiency was 0.62 in calibration period and 0.64 in validation period,which illustrated that the simulation discharge curve fit well with actual runoff processes.In the seven parameters selected,maximum velocity of baseflow Dmax ,scale factor of the largest subsoil moisture content Ws ,and thickness of soil moisture uppermost layer d1 were very sensitive,especially d1 .Observed discharges were almost in the range of 90% predicted confidence areas,except some low discharges.It can be concluded that VIC model can be used to simulate runoff processes in the upper reaches of the Heihe River basin.