Profiles of relative permittivity and electrical conductivity from unsaturated soil water content models
Profiles of relative permittivity and electrical conductivity from unsaturated soil water content models
复制标题
非饱和土壤含水量模型的相对介电常数和电导率剖面
DOI：
10.4401/ag-6990
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发表时间：
2016
影响因子：
1
通讯作者：
F. Bianchi
中科院分区：
文献类型：
--
作者：
Roberta Porretta;F. Bianchi
为了确定土壤含水量随深度和时间的变化规律，建立了不同类型土壤结构的渗透带水分扩散数学模型。从这些剖面中，我们得到了不同土壤的特征电参数，如相对介电常数（epsilon r）和电导率（sigma），以及它们随时间的变化，采用科学文献中可用的经验关系。通过数学模型进行了模拟，考虑了不同类型的土壤，其特征是砂、粘土和淤泥在结构三角形中的百分比组成，这提供了一些影响土壤保水性的物理和化学性质。由此得到的SWC模拟剖面以及相应的介电常数和电导率剖面跨越一定的数值范围，这表明了地球物理调查的最佳技术和局限性。此外，这种先验知识有助于通过测量获得的介电常数和电导率数据的阐述和解释。介电常数和电导率剖面在某些环境应用中特别有用，当土壤质地已知（或假定已知）时，如在垃圾填埋场渗滤液分散的典型情况下。由于处置废物下面或附近的土壤质地具有SWC特征，因此可以直接推断出不同深度的（epsilon r）和（sigma）的值。
A mathematical model of water diffusion in the vadose zone has been implemented for different types of soil textures in order to determine the soil water content (SWC) profiles in dependence of depth and time. From these profiles, obtained for different soils, we derived the characteristic electrical parameters, such as relative permittivity ( epsilon r ) and electrical conductivity ( sigma ), and their variation in time, employing empirical relations available in the scientific literature. The simulation through mathematical models has been performed taking into account different types of soils characterized by the percentage composition of sand, clay and silt in the textural triangle, which provides some physical and chemical properties that affect the water retention in the soil. The resulting simulated profiles of SWC and consequently permittivity and conductivity profiles, span over a certain range of values suggesting the best techniques and the limits in geophysical investigation. Moreover this a-prior knowledge helps in the elaboration and interpretation of permittivity and conductivity data obtained by the measurements. Permittivity and conductivity profiles are particularly useful in some environmental applications when the soil textures are (or supposed to be) known as in the typical case of landfill leachate dispersion. Since the soil textures beneath or nearby a disposal waste are characterized by a SWC, the values of ( epsilon r ) and (sigma) at various depth can be directly inferred.