Estimation of the Unsaturated Hydraulic Conductivity of Peat Soils: Laboratory versus Field Data
Estimation of the Unsaturated Hydraulic Conductivity of Peat Soils: Laboratory versus Field Data
复制标题
泥炭土不饱和导水率的估算：实验室数据与现场数据
DOI：
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发表时间：
2006
期刊：
影响因子：
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通讯作者：
M. T. V. Genuchten
中科院分区：
文献类型：
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作者：
K. Schwärzel;J. Šimůnek;Heiner Stoffregen;G. Wessolek;M. T. V. Genuchten
与矿质土相比，泥炭土非饱和水力特性的原位测量很少。我们使用参数估计（逆）方法从实验室和现场数据中估计排干泥炭土的保水性和导水性函数。室内数据采用传统蒸发法在小岩心上获取，野外数据采用有植被和无植被的地下水溶渗仪进行蒸发试验。没有植被的野外试验产生了高度不确定的参数，并且限制在相对较小的压头范围内。有草覆盖的渗湿仪获得了更好的结果，使泥炭土更干燥。然而，只有当优化中包含了几个参数的先验信息时，才能找到植物覆盖式渗滤仪目标函数中物理上现实的最小值。实验室测量结果与现场测量结果吻合良好。随后，通过将正演模拟与独立测量的压力头和在草地下进行的另一个渗滤仪实验的含水量进行比较，对水力功能进行了测试。利用优化后的土壤水力特性，可以很好地描述干燥过程的动力学特性。
As compared with mineral soils, there are few in situ measurements of the unsaturated hydraulic properties of peat soils available. We used parameter estimation (inverse) methods to estimate the water retention and hydraulic conductivity functions of drained peat soils from both laboratory and field data. The laboratory data were obtained on small cores using the traditional evaporation method, while the field data were obtained by means of evaporation experiments using groundwater lysimeters with and without vegetation. The field experiments without vegetation produced highly uncertain parameters and were limited to a relatively small pressure head range. Better results were obtained for the lysimeter with a grass cover that caused the peat soil to dry out more. However, a physically realistic minimum in the objective function for the plant‐covered lysimeter could be found only when prior information about several parameters was included in the optimization. Good agreement was obtained between the laboratory and field measurements. The hydraulic functions were subsequently tested by comparing forward simulations with independently measured pressure heads and water contents of an additional lysimeter experiment under grass. The dynamics of the drying process was described well using the optimized soil hydraulic properties.