基于热示踪法河流潜流带潜流通量计算参数敏感性分析——以渭河西安段为例

Sensitivity Analysis of Hyporheic Flux Calculation Parameters in Hyporheic Zone of River Based on Thermal Tracing Method—A Case of Weihe River Xi’an Section

摘要: 由于热示踪法计算河流潜流通量无法克服温度数据估计潜流交换的部分缺点，河床的空间异质性以及河床一些热学参数的选取对潜流通量计算结果影响比较大。为提高计算结果的准确性，计算参数的敏感性尤为重要。以渭河西安段为例，利用VFLUX工具箱2.0.0版对孔隙度、河床骨架热容、水热容、热弥散度、有效热传导系数代入典型值以及上下边界值通过计算得到的振幅比法结果的变化量、变化率进行敏感性分析。结果表明：在河床为深度0.05~0.70 m时，潜流通量随孔隙度、河床体积热容增大而增大，随水体积热容增大而减小。热弥散在0~0.01取值时不影响潜流通量结果。热传导系数对潜流通量的影响随深度不同而发生变化。同参数在不同深度的敏感性强弱也有所不同：水体积热容的敏感性随深度增大而变弱。孔隙度在0.15~0.40 m时敏感性最强，热传导系数在0.40~0.70 m时敏感性最强，河床体积热容在0.05~0.15 m时敏感性最强。不同参数在同深度的敏感性强弱总体为热传导系数 > 河床体积热容 > 孔隙度 > 水体积热容 > 热弥散。

Abstract: Due to the fact that the thermal tracer method to calculate the river hydroheic flux can not over-come the temperature data to estimate some of the shortcomings of subsurface exchange, the spatial heterogeneity of the riverbed and the selection of some thermal parameters of the river bed have a great influence on the calculation results of the hydroheic flux. In order to improve the accuracy of the calculation results, it is important to calculate the sensitivity of the parameters. Using the VFLUX toolbox 2.0.0, the porosity, the heat capacity of the bed skeleton, the volumetric heat capacity of water, the dispersivity, the effective heat transfer coefficient into the typical value and the upper and lower boundary values were analyzed by the calculated change rate of the amplitude ratio method. The results show that when the depth of the bed is 0.05 - 0.70 m, the hydroheic flux increases with the porosity and the heat capacity of the bed skeleton, and decreases with the increase of volumetric heat capacity of water. It does not affect the hydroheic flux results when the dispersivity in the 0 - 0.01 value. The effective heat transfer coefficient on the hydroheic flux varies with depth. The sensitivity of the same parameter at different depths is also different: the volumetric heat capacity of water decreases with depth. When the porosity is 0.15 - 0.40 m, the sensitivity is the strongest, the effective heat transfer coefficient is 0.40 - 0.70 m, the sensitivity is the strongest, and the volumetric heat capacity of the bed skeleton is the strongest at 0.05 - 0.15 m. In short, the sensitivity of different parameters at the same depth is the effective heat transfer coefficient > the volumetric heat capacity of the bed skeleton > the porosity > the volumetric heat capacity of water > the dispersivity.