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首页> 外文期刊>Cold regions science and technology >Evaluation of five composite dielectric mixing models for understanding relationships between effective permittivity and unfrozen water content
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Evaluation of five composite dielectric mixing models for understanding relationships between effective permittivity and unfrozen water content

机译：评估五个复合介质混合模型以了解有效介电常数和未冻结水含量之间的关系

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摘要

Accurate estimation of unfrozen/liquid water content (theta(1)) of soils with time domain reflectometry (TDR) is important for understanding freezing and thawing processes and hydrology in cold regions. Empirical equations and composite dielectric mixing models are the two most commonly used methods to estimate water content in unfrozen soils from TDR-measured soil effective permittivity (epsilon(eff)). However, empirical equations derived from unfrozen soil data always overestimate theta(1) in frozen soils and few studies were found to examine the validity of composite dielectric mixing models for measuring theta(1). Therefore, the objective of this study was to evaluate the sensitivities and applicability of composite dielectric mixing models for modeling the epsilon(eff)(theta(1)) relationship. Five multi-phase, composite dielectric mixing models (i.e., power law model, de Loor model, Sihvola discrete model, Sihvola confocal model, and Sphere model) were evaluated with published dataset consisting of independently measured epsilon(eff) and theta(1) on the same samples. The results show that: (1) the power law model and de Loor models are independent of configurations of dielectric mixtures; (2) the Sihvola discrete model depends on the host medium and independent on the configurations of the other components; (3) different dielectric mixing models may end up with the similar epsilon(eff)(theta(1)) relationships by parameter adjusting to represent the same problem; and (4) the de Loor model, and Sihvola discrete and confocal models are most appropriate for modeling the epsilon(eff)(theta(1)) relationship of frozen soils based on the published dataset. This study will significantly contribute to the application of TDR method for liquid water measurement in frozen soils and facilitate the understanding of freezing/thawing processes. (C) 2016 Elsevier B.V. All rights reserved.
机译：使用时域反射计（TDR）准确估算土壤的未冻结/液态水含量（theta（1））对于了解寒冷地区的冻融过程和水文学非常重要。经验方程和复合介电混合模型是从TDR测量的土壤有效介电常数（epsilon（eff））估算未冻土中水含量的两种最常用方法。但是，从未冻结的土壤数据得出的经验方程式总是高估了冻土中的theta（1），很少有研究检查用于测量theta（1）的复合介电混合模型的有效性。因此，本研究的目的是评估用于建模ε（eff）（theta（1））关系的复合介质混合模型的灵敏度和适用性。使用已发布的由独立测量的epsilon（eff）和theta（1）组成的数据集，评估了五个多相复合电介质混合模型（即幂律模型，de Loor模型，Sihvola离散模型，Sihvola共焦模型和Sphere模型）在相同的样本上。结果表明：（1）幂律模型和de Loor模型与电介质混合物的构型无关； （2）Sihvola离散模型取决于宿主介质，并且独立于其他组件的配置； （3）通过参数调整来表示相同的问题，不同的介电混合模型最终可能具有相似的epsilon（eff）（theta（1））关系； （4）de Loor模型以及Sihvola离散和共聚焦模型最适合根据已发布的数据集对冻土的epsilon（eff）（theta（1））关系进行建模。这项研究将极大地促进TDR方法在冻土中液态水测量中的应用，并有助于了解冻融过程。 （C）2016 Elsevier B.V.保留所有权利。

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  • 来源
    《Cold regions science and technology》 |2016年第10期|33-42|共10页
  • 作者

    He Hailong; Dyck Miles; Zhao Ying; Si Bingcheng; Jin Huijun; Zhang Tingjun; Lv Jialong; Wang Jinxing;

  • 作者单位

    Northwest A&F Univ, Minist Agr, Coll Nat Resources & Environm, Yangling 712100, Shaanxi, Peoples R China|Northwest A&F Univ, Minist Agr, Key Lab Plant Nutr & Agrienvironm Northwest China, Yangling 712100, Shaanxi, Peoples R China|Chinese Acad Sci, State State Key Lab Frozen Soil Engn, Cold & Arid Reg Environm & Engn Res Inst, Lanzhou 730000, Gansu, Peoples R China;

    Univ Alberta, Dept Renewable Resources, Edmonton, AB T6G 2H1, Canada;

    Northwest A&F Univ, Minist Agr, Coll Nat Resources & Environm, Yangling 712100, Shaanxi, Peoples R China|Northwest A&F Univ, Minist Agr, Key Lab Plant Nutr & Agrienvironm Northwest China, Yangling 712100, Shaanxi, Peoples R China;

    Univ Saskatchewan, Dept Soil Sci, Saskatoon, SK S7N 5A8, Canada|Northwest A&F Univ, Coll Water Resources & Architectural Engn, Yangling 712100, Shaanxi, Peoples R China;

    Chinese Acad Sci, State State Key Lab Frozen Soil Engn, Cold & Arid Reg Environm & Engn Res Inst, Lanzhou 730000, Gansu, Peoples R China;

    Lanzhou Univ, Coll Nat Resources & Environm, Lanzhou 730000, Ganshu, Peoples R China|Univ Colorado, CIRES, Boulder, CO 80309 USA;

    Northwest A&F Univ, Minist Agr, Coll Nat Resources & Environm, Yangling 712100, Shaanxi, Peoples R China|Northwest A&F Univ, Minist Agr, Key Lab Plant Nutr & Agrienvironm Northwest China, Yangling 712100, Shaanxi, Peoples R China;

    Northwest A&F Univ, Minist Agr, Coll Nat Resources & Environm, Yangling 712100, Shaanxi, Peoples R China|Northwest A&F Univ, Minist Agr, Key Lab Plant Nutr & Agrienvironm Northwest China, Yangling 712100, Shaanxi, Peoples R China;

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  • 原文格式 PDF
  • 正文语种 eng
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  • 关键词

    TDR; Dielectric mixing model; Unfrozen water content; Ice content; Frozen soil;

    机译：TDR;介电混合模型;未冻结水含量;冰含量;冻结土壤;

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