四种方法推求土壤导水参数的差别与准确性研究

利用土壤水分特征曲线拟合公式和实测的饱和导水率间接推求土壤非饱和导水参数K(θ)和D(θ)是目前大多数水文模型普遍采用的方法。以长武黑垆土为例,对其中比较流行的Broadbrige-White模型、VanGenuchten模型、Burdine模型和Mualem模型推求土壤导水参数的差别和准确性进行了比较分析。结果发现:在较高含水量范围内,4种方法推求的土壤导水参数与实测值相差很小,具有较高精度;用4种方法计算土壤水分扩散率D精度要明显高于对非饱和土壤导水率K计算精度;对黑垆土而言,用Broadbrige-White模型推求的土壤非饱和导水参数K和D精度最高。

The difference and accuracy of four methods in determining soil hydraulic parameters

The simulated equations of soil moisture characteristic curve and saturated hydraulic conductivity are widely used in the prediction of the hydraulic conductivity and water diffusivity of unsaturated soils.Taking Heilu soil as an exemple, this article analyses and compares the difference and accuracy of soil hydraulic parameters simulated by four models including Broadbrige-White model, Van Genuchten model, Burdine model and Mualem model. The results shows that the accuracy of the simulated values of the four models compared with the observed values is high when soil water content is at a high level. The simulation accuracy of water diffusivity is higher than that of hydraulic conductivity in unsaturated soil. As to Heilu soil, the accuracy of soil hydraulic parameters simulated by Broadbrige-White model is the highest among the four models.