נגישות
menu      
חיפוש מתקדם
תחביר
חפש...
הספר "אוצר וולקני"
אודות
תנאי שימוש
ניהול
קהילה:
אסיף מאגר המחקר החקלאי
פותח על ידי קלירמאש פתרונות בע"מ -
A saturation degree-dependent composite spheres model for describing the effective dielectric constant of unsaturated porous media
Year:
1998
Source of publication :
Water Resources Research
Authors :
פרידמן, שמואל
;
.
Volume :
34
Co-Authors:
Friedman, S.P., Inst. Soil, Water and Environ. Sci., Agricultural Research Organization, Volcani Center, Bet Dagan, Israel, Inst. Soil, Water and Environ. Sci., Agricultural Research Organization, Volcani Center, Bet Dagan 50250, Israel
Facilitators :
From page:
2949
To page:
2961
(
Total pages:
13
)
Abstract:
Understanding the relation between the effective dielectric constant (relative permittivity) of soils and their volumetric water content is important because measurements of the dielectric constant of soils by capacitance sensors, time domain reflectometry (TDR) probes, and remote-sensing radar devices are used to determine their moisture content. In the present study a physical model is proposed which relates the effective dielectric constant of unsaturated mineral soils at TDR frequencies to their volumetric water content, porosity, and specific surface area. It is assumed that the solid, water, and air components form a mixture of composite spheres and that the radial order of the single-phase concentric shells depends on the saturation degree of the medium. The dielectric constant of the aqueous phase is smaller than that of free water, because of interfacial solid-liquid forces, and the dependence of this reduction on the moisture content and on the specific surface area is represented here via a general approximated relationship. The model prediction is based on readily available soil properties (porosity, specific surface area, or texture), and it does not require any calibration. Tests of the model predictions against measurements made here on 3 porous media and against published data for an additional 19 media resulted in a promising agreement, with the proposed model's predictions being better than those given by the commonly used empirical relations for mineral soils. It is believed that the model performance could be further improved by better representation of the saturation degree-dependent, three-phase configuration by considering nonspherical soil particles and by a more realistic incorporation of interfacial relaxation processes.
Note:
Related Files :
Forecasting
remote sensing
soil moisture
Soils
soil surveys
Specific surface area
עוד תגיות
תוכן קשור
More details
DOI :
Article number:
Affiliations:
Database:
סקופוס
Publication Type:
מאמר
;
.
Language:
אנגלית
Editors' remarks:
ID:
20781
Last updated date:
02/03/2022 17:27
Creation date:
16/04/2018 23:39
You may also be interested in
Scientific Publication
A saturation degree-dependent composite spheres model for describing the effective dielectric constant of unsaturated porous media
34
Friedman, S.P., Inst. Soil, Water and Environ. Sci., Agricultural Research Organization, Volcani Center, Bet Dagan, Israel, Inst. Soil, Water and Environ. Sci., Agricultural Research Organization, Volcani Center, Bet Dagan 50250, Israel
A saturation degree-dependent composite spheres model for describing the effective dielectric constant of unsaturated porous media
Understanding the relation between the effective dielectric constant (relative permittivity) of soils and their volumetric water content is important because measurements of the dielectric constant of soils by capacitance sensors, time domain reflectometry (TDR) probes, and remote-sensing radar devices are used to determine their moisture content. In the present study a physical model is proposed which relates the effective dielectric constant of unsaturated mineral soils at TDR frequencies to their volumetric water content, porosity, and specific surface area. It is assumed that the solid, water, and air components form a mixture of composite spheres and that the radial order of the single-phase concentric shells depends on the saturation degree of the medium. The dielectric constant of the aqueous phase is smaller than that of free water, because of interfacial solid-liquid forces, and the dependence of this reduction on the moisture content and on the specific surface area is represented here via a general approximated relationship. The model prediction is based on readily available soil properties (porosity, specific surface area, or texture), and it does not require any calibration. Tests of the model predictions against measurements made here on 3 porous media and against published data for an additional 19 media resulted in a promising agreement, with the proposed model's predictions being better than those given by the commonly used empirical relations for mineral soils. It is believed that the model performance could be further improved by better representation of the saturation degree-dependent, three-phase configuration by considering nonspherical soil particles and by a more realistic incorporation of interfacial relaxation processes.
Scientific Publication
You may also be interested in