Ground penetrating radar in temperate ice: englacial water inclusions as limiting factor for data interpretation

Ground penetrating radar (GPR) has been extensively used in glaciology to infer glacier's ice thickness, liquid water content, water drainage pathways, and other properties. The interpretation of such GPR data is not always straightforward and for temperate glaciers, the signal is often affecte...

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Main Authors: Christophe Ogier, Dirk-Jan van Manen, Hansruedi Maurer, Ludovic Räss, Marian Hertrich, Andreas Bauder, Daniel Farinotti
Format: Article
Language:English
Published: Cambridge University Press 2023-12-01
Series:Journal of Glaciology
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Online Access:https://www.cambridge.org/core/product/identifier/S0022143023000680/type/journal_article
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author Christophe Ogier
Dirk-Jan van Manen
Hansruedi Maurer
Ludovic Räss
Marian Hertrich
Andreas Bauder
Daniel Farinotti
author_facet Christophe Ogier
Dirk-Jan van Manen
Hansruedi Maurer
Ludovic Räss
Marian Hertrich
Andreas Bauder
Daniel Farinotti
author_sort Christophe Ogier
collection DOAJ
description Ground penetrating radar (GPR) has been extensively used in glaciology to infer glacier's ice thickness, liquid water content, water drainage pathways, and other properties. The interpretation of such GPR data is not always straightforward and for temperate glaciers, the signal is often affected by strong scattering and attenuation. It has often been suggested that such effects originate from englacial water inclusions, since water and ice have a large contrast in their di-electric permittivity. To investigate such effects quantitatively, we perform an extensive numerical modeling study of GPR signals. By exploring how different liquid water contents (LWC) and water-inclusions size affect the GPR signal, we show that their effects are much larger than the potential presence of a wet snowpack or a heterogeneous distribution of ice permittivity. In particularly, we show that the presence of such water inclusions is a necessary and sufficient condition for reproducing the typical characteristics of GPR data acquired in the field. Further, we find that for 25 MHz GPR antennas, a bulk LWC $\gtrsim$ 0.2%, associated with decimeters-scale water inclusions already limits bedrock detectability for ice thicknesses $\gtrsim 100$ m. Since these values are typical for Alpine glaciers, they clarify why the quality of GPR data is often poor in such environments.
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issn 0022-1430
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language English
publishDate 2023-12-01
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series Journal of Glaciology
spelling doaj-art-e62ff71b935949a2b6feb6ab5feed0772025-08-20T02:33:44ZengCambridge University PressJournal of Glaciology0022-14301727-56522023-12-01691874188510.1017/jog.2023.68Ground penetrating radar in temperate ice: englacial water inclusions as limiting factor for data interpretationChristophe Ogier0https://orcid.org/0000-0002-5526-6071Dirk-Jan van Manen1Hansruedi Maurer2https://orcid.org/0000-0003-0131-1006Ludovic Räss3https://orcid.org/0000-0002-1136-899XMarian Hertrich4Andreas Bauder5https://orcid.org/0000-0001-7197-7706Daniel Farinotti6https://orcid.org/0000-0003-3417-4570Laboratory of Hydraulics, Hydrology and Glaciology (VAW), ETH Zurich, Zurich, Switzerland Swiss Federal Institute for Forest, Snow and Landscape Research (WSL), Birmensdorf, SwitzerlandInstitute of Geophysics, ETH Zurich, Zurich, SwitzerlandInstitute of Geophysics, ETH Zurich, Zurich, SwitzerlandLaboratory of Hydraulics, Hydrology and Glaciology (VAW), ETH Zurich, Zurich, Switzerland Swiss Federal Institute for Forest, Snow and Landscape Research (WSL), Birmensdorf, SwitzerlandInstitute of Geophysics, ETH Zurich, Zurich, SwitzerlandLaboratory of Hydraulics, Hydrology and Glaciology (VAW), ETH Zurich, Zurich, Switzerland Swiss Federal Institute for Forest, Snow and Landscape Research (WSL), Birmensdorf, SwitzerlandLaboratory of Hydraulics, Hydrology and Glaciology (VAW), ETH Zurich, Zurich, Switzerland Swiss Federal Institute for Forest, Snow and Landscape Research (WSL), Birmensdorf, SwitzerlandGround penetrating radar (GPR) has been extensively used in glaciology to infer glacier's ice thickness, liquid water content, water drainage pathways, and other properties. The interpretation of such GPR data is not always straightforward and for temperate glaciers, the signal is often affected by strong scattering and attenuation. It has often been suggested that such effects originate from englacial water inclusions, since water and ice have a large contrast in their di-electric permittivity. To investigate such effects quantitatively, we perform an extensive numerical modeling study of GPR signals. By exploring how different liquid water contents (LWC) and water-inclusions size affect the GPR signal, we show that their effects are much larger than the potential presence of a wet snowpack or a heterogeneous distribution of ice permittivity. In particularly, we show that the presence of such water inclusions is a necessary and sufficient condition for reproducing the typical characteristics of GPR data acquired in the field. Further, we find that for 25 MHz GPR antennas, a bulk LWC $\gtrsim$ 0.2%, associated with decimeters-scale water inclusions already limits bedrock detectability for ice thicknesses $\gtrsim 100$ m. Since these values are typical for Alpine glaciers, they clarify why the quality of GPR data is often poor in such environments.https://www.cambridge.org/core/product/identifier/S0022143023000680/type/journal_articleGlacier geophysicsground-penetrating radarice thickness measurements
spellingShingle Christophe Ogier
Dirk-Jan van Manen
Hansruedi Maurer
Ludovic Räss
Marian Hertrich
Andreas Bauder
Daniel Farinotti
Ground penetrating radar in temperate ice: englacial water inclusions as limiting factor for data interpretation
Journal of Glaciology
Glacier geophysics
ground-penetrating radar
ice thickness measurements
title Ground penetrating radar in temperate ice: englacial water inclusions as limiting factor for data interpretation
title_full Ground penetrating radar in temperate ice: englacial water inclusions as limiting factor for data interpretation
title_fullStr Ground penetrating radar in temperate ice: englacial water inclusions as limiting factor for data interpretation
title_full_unstemmed Ground penetrating radar in temperate ice: englacial water inclusions as limiting factor for data interpretation
title_short Ground penetrating radar in temperate ice: englacial water inclusions as limiting factor for data interpretation
title_sort ground penetrating radar in temperate ice englacial water inclusions as limiting factor for data interpretation
topic Glacier geophysics
ground-penetrating radar
ice thickness measurements
url https://www.cambridge.org/core/product/identifier/S0022143023000680/type/journal_article
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