A Simple Model to Predict Hydraulic Conductivity in Medium to Dry Soil From the Water Retention Curve
A Simple Model to Predict Hydraulic Conductivity in Medium to Dry Soil From the Water Retention Curve
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DOI：
10.1029/2020wr029211
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发表时间：
2021-03
影响因子：
5.4
通讯作者：
A. Peters;Tobias L. Hohenbrink;S. Iden;W. Durner
中科院分区：
文献类型：
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作者：
A. Peters;Tobias L. Hohenbrink;S. Iden;W. Durner
土壤水力特性的数学表示对于模拟土壤中的水、溶质和能量传输至关重要。所建立的保水性和导水率曲线模型考虑了毛细管保水性和电导率，但忽略了膜和孔隙角落中的水吸附和水流动。因此，它们适用于模拟中等至潮湿湿度范围内的流动和传输过程，但在干燥土壤中容易失效。 Peters (2013, https://doi.org/10.1002/wrcr.20548; 2014, https://doi.org/10.1002/2014wr016107) 以及 Iden 和 Durner (2014, https://doi.org/10.1002/2014wr015937) 开发的模型系统（PDI 以下）是一个简单的参数化框架，克服了这些结构性缺陷。然而，它需要一个附加参数来缩放非毛细管流占主导地位的湿度范围内的水力传导率曲线。需要测量的电导率数据来确定该比例参数并计算整个湿度范围内的水力电导率。在这篇文章中，我们首先表明原始 PDI 模型与多孔介质中薄膜电导率的综合模型非常一致。然后，我们推导出一种基于物理的方法来根据保水曲线预测薄膜的电导率。这种改进的 PDI 模型与已建立的模型具有相同数量的参数，并且在已知保水数据和饱和电导率的情况下，可以提供包括非毛细管流在内的水力电导率曲线的完整预测。应用涵盖广泛纹理的文献数据表明，与 van Genuchten/Mualem 模型相比，电导率预测提高了五倍。
The mathematical representation of the soil hydraulic properties is of central importance for modeling water, solute and energy transport in soils. The established models of the water retention and hydraulic conductivity curves account for capillary water retention and conductivity, but neglect water adsorption and water flow in films and pore corners. They are therefore suited for modeling flow and transport processes in the medium to wet moisture range, but are susceptible to failure in dry soil. The model system developed by Peters (2013, https://doi.org/10.1002/wrcr.20548; 2014, https://doi.org/10.1002/2014wr016107) and Iden and Durner (2014, https://doi.org/10.1002/2014wr015937) (PDI in the following) is a simple parametric framework that overcomes these structural shortcomings. However, it requires one additional parameter to scale the hydraulic conductivity curve in the moisture range where non‐capillary flow dominates. Measured conductivity data are required to determine this scaling parameter and to compute the hydraulic conductivity over the complete moisture range. In this contribution, we first show that the original PDI model is in close agreement with a comprehensive model for film conductivity in porous media. We then derive a physically‐based approach to predict the film conductivity from the water retention curve. This improved PDI model has the same number of parameters as established models and provides a complete prediction of the hydraulic conductivity curve including non‐capillary flow if water retention data and the saturated conductivity are known. Application to literature data covering a broad range of textures shows an improvement of the conductivity prediction by the factor five if compared to the van Genuchten/Mualem model.