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An empirical model for the complex dielectric permittivity of soils as a function of water contentRecent measurements on the dielectric properties of soils have shown that the variation of dielectric constant with moisture content depends on soil types. The observed dielectric constant increases only slowly with moisture content up to a transition point. Beyond the transition it increases rapidly with moisture content. The moisture value at transition region was found to be higher for high clay content soils than for sandy soils. Many mixing formulas reported in the literature were compared with, and were found incompatible with, the measured dielectric variations of soil-water mixtures. A simple empirical model was proposed to describe the dielectric behavior of the soil-water mixtures. This model employs the mixing of either the dielectric constants or the refraction indices of ice, water, rock, and air, and treats the transition moisture value as an adjustable parameter. The calculated mixture dielectric constants from the model were found to be in reasonable agreement with the measured results over the entire moisture range of 0-0.5 cu cm/cu cm. The transition moistures derived from the model range from 0.16 to 0.33 and are strongly correlated with the wilting points of the soils estimated from their textures. This relationship between transition moisture and wilting point provides a means of estimating soil dielectric properties on the basis of texture information.
Document ID
19810027566
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Wang, J. R.
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Schmugge, T. J.
(NASA Goddard Space Flight Center Laboratory for Atmospheric Sciences, Greenbelt, Md., United States)
Date Acquired
August 11, 2013
Publication Date
October 1, 1980
Publication Information
Publication: IEEE Transactions on Geoscience and Remote Sensing
Volume: GE-18
Subject Category
Earth Resources And Remote Sensing
Accession Number
81A11970
Distribution Limits
Public
Copyright
Other

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