Noninvasive Estimation of Water Retention Parameters by Observing the Capillary Fringe with Magnetic Resonance Sounding
Noninvasive Estimation of Water Retention Parameters by Observing the Capillary Fringe with Magnetic Resonance Sounding
复制标题
通过磁共振探测观察毛细管边缘无创估计保水参数
DOI：
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发表时间：
2014
期刊：
影响因子：
--
通讯作者：
T. Günther
中科院分区：
文献类型：
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作者：
S. Costabel;T. Günther
磁共振测深法是研究含水层系统分层的常用方法。与其他水文地球物理方法不同的是，它对地下水含量的直接敏感性。MRS数据的反演产生地下水含量分布，而不需要岩石物理模型。仪器的最新发展，即，减少的仪器死时间和先进的噪声消除策略使得能够使用该方法来研究包气带。一种可能的方式来解释MRS测量与水分保持（WR）参数的重点是一个反演方法，直接提供WR参数通过建模的毛细管边缘（CF反演）。我们进一步发展了这种反演，以解释不同的WR模型，并提出了一个敏感性研究的基础上合成和真实的现场数据。为了评估CF反演的普遍适用性，我们分析了不同测量布局的分辨率特性和不同现实场景的参数不确定性。在中等噪音条件下，如果地下水位位置已知，则可以可靠地估计除残余含水量之外的所有WR参数。对于较大的CF，估计的孔隙分布指数估计的相对准确性更好。直径为5 m的小型测量回路可实现<10 m的浅层调查深度的最佳分辨率。
The magnetic resonance sounding (MRS) method is usually applied for delineation and characterization of aquifer system stratification. Its unique property, distinct from other hydrogeophysical methods, is the direct sensitivity to water content in the subsurface. The inversion of MRS data yields the subsurface water content distribution without need of a petrophysical model. Recent developments in instrumentation, i.e., decreased instrumental dead times and advanced noise cancellation strategies, enable the use of this method for investigating the vadose zone. A possible way to interpret MRS measurements with focus on water retention (WR) parameters is an inversion approach that directly provides WR parameters by modeling the capillary fringe (CF inversion). We have developed this kind of inversion further to account for different WR models and present a sensitivity study based on both synthetic and real field data. To assess the general applicability of the CF inversion, we analyzed the resolution properties for different measurement layouts and the parameter uncertainties for different realistic scenarios. Under moderate noise conditions and if the water table position is known, all WR parameters except the residual water content can be reliably estimated. The relative accuracy of the estimated pore distribution index estimation is better for larger CF. Small measurement loops of 5‐m diameter achieve the best resolution for shallow investigation depths of <10 m.
影响因子：
1.6
作者：
M. Müller‐Petke;S. Costabel
通讯作者：
M. Müller‐Petke;S. Costabel