Inverse Mobile–Immobile Modeling of Transport During Transient Flow: Effects of Between‐Domain Transfer and Initial Water Content
Inverse Mobile–Immobile Modeling of Transport During Transient Flow: Effects of Between‐Domain Transfer and Initial Water Content
复制标题
瞬态流动过程中输运的逆移动-不动模型：域间传递和初始含水量的影响
DOI：
10.2136/vzj2004.1309
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发表时间：
2004
期刊：
影响因子：
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通讯作者：
J. Šimůnek
中科院分区：
文献类型：
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作者：
J. Köhne;S. Köhne;B. Mohanty;J. Šimůnek
流动-固定流动模型(MIM)很少被用于可变饱和水流和污染物运移测量的反向模拟。我们评价了两种基于相对饱和度(Se)差和压差(H)的水分跨流动和非流动区域水分迁移的MIM(H)方法，用于反向模拟团聚体土壤中的瞬变水流和BR-−运移。6根原状AP土柱(长14.7 cm，直径14.7 cm)在湿润、中等和干燥初始含水率下，用0.005 L BR−溶液1 000 mg L−1，然后灌溉1 cm h−1 3h，7和14 d后进行两次类似的灌溉，测量深度2.8和12.8 cm处的压头、平均土柱含水率、出水和出水溶质浓度。这些试验信息被用于同时优化van Genuchten土壤流动和静止区域的水力参数、分散度以及水分和溶质迁移的一阶速率系数。总共估计了8个MIM参数(Se)和10个MIM参数(H)。逆MIM方法充分描述了各种水力和输运数据。湿气和干气的物理不平衡比中间初始水分更明显，而初始水分对总的BR−损失没有明显的影响。对于干湿初始条件，参数估计似乎相当可靠，但流动和不流动地区的饱和水分含量高度相关。MIM(H)得到的参数在物理上似乎与观测结果更一致，但需要比MIM(Se)更小的时间步长来克服压头的振荡。两种MIM方法都适用于变饱和渗流中物理非平衡运移的逆模拟。
Mobile–immobile models (MIM) have rarely been used for inverse simulation of measurements of variably saturated water flow and contaminant transport. We evaluated two MIM approaches with water transfer across the mobile and immobile regions either based on relative saturation (Se) differences, MIM(Se), or pressure head (h) differences, MIM(h), for inverse simulation of transient water flow and Br− transport in aggregated soil. Six undisturbed Ap soil columns (14.7‐cm length and diameter) at wet, medium, and dry initial water contents were subjected to application of 0.005 L Br− solution of 1000 mg L−1 and subsequent irrigation of 1 cm h−1 for 3 h. Two similar irrigations were applied after 7 and 14 d. Measurements comprised pressure heads at depths of 2.8 and 12.8 cm, average soil column water contents, outflow, and effluent solute concentrations. This experimental information was used for simultaneous optimization of van Genuchten soil hydraulic parameters for mobile and immobile regions, the dispersivity, and the first‐order rate coefficients for water and solute transfer. In total, eight parameters were estimated for MIM(Se) and 10 parameters for MIM(h). The inverse MIM approaches described the various hydraulic and transport data adequately. Physical nonequilibrium was more pronounced for wet and dry than for intermediate initial moisture, while initial moisture had no obvious effect on the total Br− lost. For wet and dry initial conditions, parameter estimates seemed fairly reliable, with the exception of the highly correlated saturated water contents in mobile and immobile regions. MIM(h) yielded parameters that appeared physically more consistent with observations, but required smaller time steps than MIM(Se) to overcome oscillations of pressure heads. Both MIM approaches were found to be suitable for inverse simulation of physical nonequilibrium transport during variably saturated flow.