Effects of near surface soil moisture profiles during evaporation on far-field ground-penetrating radar data: A numerical study

Handle URI:
http://hdl.handle.net/10754/562503
Title:
Effects of near surface soil moisture profiles during evaporation on far-field ground-penetrating radar data: A numerical study
Authors:
Moghadas, Davood; Jadoon, Khan; Vanderborght, Jan P.; Lambot, Sébastien; Vereecken, Harry
Abstract:
We theoretically investigated the effect of vapor flow on the drying front that develops in soils when water evaporates from the soil surface and on GPR data. The results suggest the integration of the full-wave GPR model with a coupled water, vapor, and heat flow model to accurately estimate the soil hydraulic properties. We investigated the Effects of a drying front that emerges below an evaporating soil surface on the far-field ground-penetrating radar (GPR) data. First, we performed an analysis of the width of the drying front in soils with 12 different textures by using an analytical model. Then, we numerically simulated vertical soil moisture profiles that develop during evaporation for the soil textures. We performed the simulations using a Richards flow model that considers only liquid water flow and a model that considers coupled water, vapor, and heat flows. The GPR signals were then generated from the simulated soil water content profiles taking into account the frequency dependency of apparent electrical conductivity and dielectric permittivity. The analytical approach indicated that the width of the drying front at the end of Stage I of the evaporation was larger in silty soils than in other soil textures and smaller in sandy soils. We also demonstrated that the analytical estimate of the width of the drying front can be considered as a proxy for the impact that a drying front could have on far-field GPR data. The numerical simulations led to the conclusion that vapor transport in soil resulted in S-shaped soil moisture profiles, which clearly influenced the GPR data. As a result, vapor flow needs to be considered when GPR data are interpreted in a coupled inversion approach. Moreover, the impact of vapor flow on the GPR data was larger for silty than for sandy soils. These Effects on the GPR data provide promising perspectives regarding the use of radars for evaporation monitoring. © Soil Science Society of America 5585 Guilford Rd., Madison, WI 53711 USA. All rights reserved.
KAUST Department:
Water Desalination and Reuse Research Center (WDRC); Water Desalination and Reuse Research Center
Publisher:
Soil Science Society of America
Journal:
Vadose Zone Journal
Issue Date:
2013
DOI:
10.2136/vzj2012.0138
Type:
Article
ISSN:
15391663
Sponsors:
D. Moghadas is funded by the research unit Multi-scale Interfaces in Unsaturated Soil (MUSIS) of the DFG FOR 1083 (Deutsche Forschungsgemeinschaft).
Appears in Collections:
Articles; Water Desalination and Reuse Research Center (WDRC)

Full metadata record

DC FieldValue Language
dc.contributor.authorMoghadas, Davooden
dc.contributor.authorJadoon, Khanen
dc.contributor.authorVanderborght, Jan P.en
dc.contributor.authorLambot, Sébastienen
dc.contributor.authorVereecken, Harryen
dc.date.accessioned2015-08-03T10:40:32Zen
dc.date.available2015-08-03T10:40:32Zen
dc.date.issued2013en
dc.identifier.issn15391663en
dc.identifier.doi10.2136/vzj2012.0138en
dc.identifier.urihttp://hdl.handle.net/10754/562503en
dc.description.abstractWe theoretically investigated the effect of vapor flow on the drying front that develops in soils when water evaporates from the soil surface and on GPR data. The results suggest the integration of the full-wave GPR model with a coupled water, vapor, and heat flow model to accurately estimate the soil hydraulic properties. We investigated the Effects of a drying front that emerges below an evaporating soil surface on the far-field ground-penetrating radar (GPR) data. First, we performed an analysis of the width of the drying front in soils with 12 different textures by using an analytical model. Then, we numerically simulated vertical soil moisture profiles that develop during evaporation for the soil textures. We performed the simulations using a Richards flow model that considers only liquid water flow and a model that considers coupled water, vapor, and heat flows. The GPR signals were then generated from the simulated soil water content profiles taking into account the frequency dependency of apparent electrical conductivity and dielectric permittivity. The analytical approach indicated that the width of the drying front at the end of Stage I of the evaporation was larger in silty soils than in other soil textures and smaller in sandy soils. We also demonstrated that the analytical estimate of the width of the drying front can be considered as a proxy for the impact that a drying front could have on far-field GPR data. The numerical simulations led to the conclusion that vapor transport in soil resulted in S-shaped soil moisture profiles, which clearly influenced the GPR data. As a result, vapor flow needs to be considered when GPR data are interpreted in a coupled inversion approach. Moreover, the impact of vapor flow on the GPR data was larger for silty than for sandy soils. These Effects on the GPR data provide promising perspectives regarding the use of radars for evaporation monitoring. © Soil Science Society of America 5585 Guilford Rd., Madison, WI 53711 USA. All rights reserved.en
dc.description.sponsorshipD. Moghadas is funded by the research unit Multi-scale Interfaces in Unsaturated Soil (MUSIS) of the DFG FOR 1083 (Deutsche Forschungsgemeinschaft).en
dc.publisherSoil Science Society of Americaen
dc.titleEffects of near surface soil moisture profiles during evaporation on far-field ground-penetrating radar data: A numerical studyen
dc.typeArticleen
dc.contributor.departmentWater Desalination and Reuse Research Center (WDRC)en
dc.contributor.departmentWater Desalination and Reuse Research Centeren
dc.identifier.journalVadose Zone Journalen
dc.contributor.institutionAgrosphere (IBG-3), Institute of Bio- and Geosciences, Forschungszentrum Jülich, GmbH, 52425 Jülich, Germanyen
dc.contributor.institutionEarth and Life Institute, Université catholique de Louvain, Croix du Sud 2 Box, L7.05.02, B-1348 Louvain-la-Neuve, Belgiumen
kaust.authorJadoon, Khanen
All Items in KAUST are protected by copyright, with all rights reserved, unless otherwise indicated.