Development and application of a fully integrated model for unsaturated-saturated nitrogen reactive transport
Development and application of a fully integrated model for unsaturated-saturated nitrogen reactive transport
复制标题
不饱和-饱和氮反应输运全集成模型的开发与应用
DOI：
10.1016/j.agwat.2016.10.017
复制
发表时间：
2017
影响因子：
6.7
通讯作者：
Shi Liangsheng
中科院分区：
文献类型：
--
作者：
Zhu Yan;Yang Jinzhong;Ye Ming;Sun Huaiwei;Shi Liangsheng
本文提出了一个完全集成的模型来模拟两种主要氮种铵和硝态氮的非饱和-饱和耦合流动和反应输运。本研究的主要贡献是在建立单一物种的非饱和-饱和流动和溶质输运耦合模型的基础上，建立了模拟氮反应输运所需的生物地球化学反应的数学模型和新的计算机代码。通过与另一种模型的模拟结果对比，验证了计算机代码的正确性。在模拟氮反应输运的两个实际案例中，对模型进行了标定和验证。两种情况分别为采用污水灌溉的试验田规模和采用化粪池出水入渗的田间规模。数值模拟结果的定量评价表明，新模型和计算机程序能够准确地模拟野外观测的含水率、地下水位高程和氮浓度。例如，模拟含水率的均方根误差可以小到0.01。该代码计算效率高，可以通过大量的计算节点和时间步长捕获野外尺度上氮浓度的时空变化趋势。该模型是一种很有前途的工具，可用于农业和城市环境中复杂条件下的大尺度水流和氮的转化与运移建模。
This paper presents a fully integrated model to simulate coupled unsaturated-saturated flow and reactive transport of ammonium and nitrate, the two major nitrogen species. Based on our previous work of developing a coupled model of unsaturated-saturated flow and solute transport of a single species, the key contribution of this study is to develop a new mathematical model and the new computer code for a comprehensive list of biogeochemical reactions, which are necessary for simulating nitrogen reactive transport. The computer code is verified by comparing its simulated results with those obtained using another model for a synthetic case. Model calibration and validation are conducted for two real-world cases to simulate nitrogen reactive transport. The two cases are at the experimental plot scale with the sewage water irrigation and at the field scale with the septic tank effluent infiltration, respectively. Quantitative evaluation of the numerical modeling results indicates that the new model and computer code can accurately simulate field observations of moisture content, water table elevation, and nitrogen concentration. For example, the root mean square error for simulating moisture content can be as small as 0.01. The code is computationally efficient to capture spatial and temporal trends of nitrogen concentrations at the field scale with a large number of computational nodes and time steps. The fully integrated model is a promising tool for large-scale modeling of water flow and nitrogen transformation and transport under complex conditions in agricultural and urban environments.