An explicit hydrological algorithm for basic flow and transport equations and its application in agro-hydrological models for water and nitrogen dynamics
An explicit hydrological algorithm for basic flow and transport equations and its application in agro-hydrological models for water and nitrogen dynamics
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DOI：
10.1016/j.agwat.2010.08.004
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发表时间：
2010-12
期刊：
影响因子：
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通讯作者：
Kefeng Zhang;Zhang Tu-qiao;Dejun Yang
中科院分区：
文献类型：
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作者：
Kefeng Zhang;Zhang Tu-qiao;Dejun Yang
水文模拟是农业水文模型的关键组成部分，用于优化资源利用和最大限度地减少农业环境后果。在这项研究中，我们将Yang等人（2009）求解基本土壤水分流动方程的简单显式算法扩展到溶质运移方程。该算法的主要特点是在求解土壤水分和溶质运移方程时采用均匀的土层厚度和较小的时间步长，从而可以逐层进行计算。这大大简化了使用基本方程模拟土壤中水和溶质运移的过程。通过数值试验，将该算法与复有限元数值格式进行了对比，并对不同土壤水分和溶质运移进行了模拟。结果表明，在土层厚度为5cm、时间步长为0.001d的情况下，该算法能够达到与有限元法相同的精度。对小麦田间试验数据进行的水氮动态模拟试验表明，该算法的预测结果与剖面不同深度的土壤水分和矿质氮浓度随时间变化的实测值吻合较好，表明该算法具有较好的预测效果，可以可靠地应用于农业水文模型中。该算法的简单性和准确性将鼓励科学家在未来更多地使用土壤水分和溶质运移的基本方程，以提高农业水文模型的性能。
Hydrological simulation is a key component in argo-hydrological models for optimizing resources use and minimizing the environmental consequences in agriculture. In this study we extended a simple and explicit algorithm for solving the basic soil water flow equation by Yang et al. (2009) to the solute transport equation. The key feature of the algorithm is to use a uniform soil layer thickness and a small time step in solving the soil water and solute transport equations, so that the calculations can be made on a layer basis. This drastically simplifies the procedure of modeling water and solute transport in soil using the basic equations. The proposed algorithm was tested against the complex finite element (FE) numerical scheme in simulating soil water and solute transport in different soils via numerical experiments. The results showed that the proposed algorithm with a uniform soil layer thickness of 5cm and a small time step of 0.001d was able to achieve the identical accuracy as the FE method. Tests of the proposed algorithm in simulating water and nitrogen dynamics against data from a field experiment on wheat revealed that the predicted results with the simple algorithm were in good agreement with the time-course measurements of soil water and mineral N concentration at the various depths in the profile, suggesting that the proposed algorithm performed well and can be reliably applied in agro-hydrological models. The simplicity and accuracy of the algorithm will encourage scientists to use basic equations for soil water and solute transport more in the future for improving performance of agro-hydrological models.