Transect Scale Solute Transport Measured by Time Domain Reflectometry
Transect Scale Solute Transport Measured by Time Domain Reflectometry
复制标题
通过时域反射法测量横断面尺度溶质迁移
DOI：
10.2166/nh.2002.0020
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发表时间：
2002
影响因子：
2.7
通讯作者：
R. Berndtsson
中科院分区：
文献类型：
--
作者：
M. Persson;R. Berndtsson
在田间条件下进行了两个准稳态溶质运移实验。实验I中的通量为40 mm/d，实验2中的通量为18.7 mm/d。水含量（θ）和居民浓度（C-r）的测量，采用64时域反射仪探头在深度范围从0.05至0.90米。在现场对每个探头位置的C-r测量值进行原位校准。对流扩散方程（CDE）和对流对数正态传递函数（CLT）模型拟合的穿透曲线（BTC）。结果表明，指状流，这已被证明存在于以前的研究这种土壤。实验1中指宽较大，导致水平不均匀性较小，溶质运移速度相对较小。手指的位置是一致的两个实验之间的速度和质量平衡场之间的高度相关性。质量平衡计算表明，在溶质应用后一天，在深度上积分的溶质质量大于整个实验的质量平衡（在时间上积分）。可能的原因是溶质通过水平流穿过Ap/E层位边界被输送出测量体积。对输运参数的研究表明，CDE和CLT模型都可以成功地用于预测大多数个体BTC。水平平均的全球CDE和CLT模型也适用于数据。在实验1中，CDE模型更好地模拟了全局溶质运移，而在实验2中，CLT模型更好。这项研究清楚地表明，在不同含水量的现场实验中，使用TDR与原位校准技术的适用性。（减）
Two quasi steady-state solute transport experiments were carried out in a loamy sand under field conditions. The flux was 40 mm/d in experiment I and 18.7 mm/d in experiment 2. Both water content (theta) and resident concentration (C-r) measurements were taken using 64 time domain reflectometry probes at depths ranging from 0.05 to 0.90 m. The C-r measurement was calibrated in situ for each probe location in the field. The convective dispersive equation (CDE) and convective lognormal transfer function (CLT) models were fitted to the breakthrough curves (BTCs). The results indicated fingered flow, which has been shown to exist in previous studies of this soil. The finger width was larger in experiment 1 leading to smaller horizontal heterogeneity and a relatively smaller solute transport velocity. The location of the fingers was consistent between the two experiments resulting in a high correlation between the velocity and mass balance fields. Mass balance calculations showed that the solute mass integrated over depth one day after the solute application was larger than the mass balance for the entire experiment (integrated over time). The probable reason being that solutes were transported out of the measurement volume by horizontal flow across the Ap/E horizon boundary. The investigation of the transport parameters revealed that both the CDE and CLT models could be successfully used to predict most individual BTCs. Horizontally averaged global CDE and CLT models were also fitted to the data. Global solute transport was better modeled with the CDE model in experiment 1, while in experiment 2, the CLT model was better. This study clearly shows the applicability of using TDR with the in situ calibration technique in field experiments with varying water content. (Less)