Entrained Water in Basal Ice Suppresses Radar Bed‐Echo Power at Active Subglacial Lakes
Abstract Subglacial lakes have been mapped across Antarctica with two methods, radio‐echo sounding (RES) and ice‐surface deformation. At sites where both are coincident, these methods typically provide conflicting interpretations about the ice‐bed interface. With a single exception, active subglacia...
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| Format: | Article |
| Language: | English |
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Wiley
2024-07-01
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| Series: | Geophysical Research Letters |
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| Online Access: | https://doi.org/10.1029/2024GL109248 |
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| author | B. H. Hills M. R. Siegfried D. M. Schroeder |
| author_facet | B. H. Hills M. R. Siegfried D. M. Schroeder |
| author_sort | B. H. Hills |
| collection | DOAJ |
| description | Abstract Subglacial lakes have been mapped across Antarctica with two methods, radio‐echo sounding (RES) and ice‐surface deformation. At sites where both are coincident, these methods typically provide conflicting interpretations about the ice‐bed interface. With a single exception, active subglacial lakes identified by surface deformation do not display the expected flat, bright, and specular bed reflection in RES data, characteristic of non‐active lakes. This observational conundrum suggests that our understanding of Antarctic subglacial hydrology, especially beneath important fast‐moving ice streams, remains incomplete. Here, we use an airborne RES campaign that surveyed a well‐characterized group of active subglacial lakes on lower Mercer and Whillans ice streams, West Antarctica, to explore inconsistency between the two observational techniques. We test hypotheses of increased scattering and attenuation due to the presence of an active subglacial lake system that could suppress reflected bed‐echo power for RES observations in these locations, finding that entrained water is most plausible. |
| format | Article |
| id | doaj-art-71b6fdc47bc9411d86fa779dab8856cd |
| institution | OA Journals |
| issn | 0094-8276 1944-8007 |
| language | English |
| publishDate | 2024-07-01 |
| publisher | Wiley |
| record_format | Article |
| series | Geophysical Research Letters |
| spelling | doaj-art-71b6fdc47bc9411d86fa779dab8856cd2025-08-20T02:04:21ZengWileyGeophysical Research Letters0094-82761944-80072024-07-015113n/an/a10.1029/2024GL109248Entrained Water in Basal Ice Suppresses Radar Bed‐Echo Power at Active Subglacial LakesB. H. Hills0M. R. Siegfried1D. M. Schroeder2Department of Geophysics Colorado School of Mines Golden CO USADepartment of Geophysics Colorado School of Mines Golden CO USADepartment of Geophysics Stanford University Stanford CA USAAbstract Subglacial lakes have been mapped across Antarctica with two methods, radio‐echo sounding (RES) and ice‐surface deformation. At sites where both are coincident, these methods typically provide conflicting interpretations about the ice‐bed interface. With a single exception, active subglacial lakes identified by surface deformation do not display the expected flat, bright, and specular bed reflection in RES data, characteristic of non‐active lakes. This observational conundrum suggests that our understanding of Antarctic subglacial hydrology, especially beneath important fast‐moving ice streams, remains incomplete. Here, we use an airborne RES campaign that surveyed a well‐characterized group of active subglacial lakes on lower Mercer and Whillans ice streams, West Antarctica, to explore inconsistency between the two observational techniques. We test hypotheses of increased scattering and attenuation due to the presence of an active subglacial lake system that could suppress reflected bed‐echo power for RES observations in these locations, finding that entrained water is most plausible.https://doi.org/10.1029/2024GL109248radio echo soundingsubglacial lakeice‐stream dynamicssubglacial hydrologybasal reflectivityWhillans subglacial lake |
| spellingShingle | B. H. Hills M. R. Siegfried D. M. Schroeder Entrained Water in Basal Ice Suppresses Radar Bed‐Echo Power at Active Subglacial Lakes Geophysical Research Letters radio echo sounding subglacial lake ice‐stream dynamics subglacial hydrology basal reflectivity Whillans subglacial lake |
| title | Entrained Water in Basal Ice Suppresses Radar Bed‐Echo Power at Active Subglacial Lakes |
| title_full | Entrained Water in Basal Ice Suppresses Radar Bed‐Echo Power at Active Subglacial Lakes |
| title_fullStr | Entrained Water in Basal Ice Suppresses Radar Bed‐Echo Power at Active Subglacial Lakes |
| title_full_unstemmed | Entrained Water in Basal Ice Suppresses Radar Bed‐Echo Power at Active Subglacial Lakes |
| title_short | Entrained Water in Basal Ice Suppresses Radar Bed‐Echo Power at Active Subglacial Lakes |
| title_sort | entrained water in basal ice suppresses radar bed echo power at active subglacial lakes |
| topic | radio echo sounding subglacial lake ice‐stream dynamics subglacial hydrology basal reflectivity Whillans subglacial lake |
| url | https://doi.org/10.1029/2024GL109248 |
| work_keys_str_mv | AT bhhills entrainedwaterinbasalicesuppressesradarbedechopoweratactivesubglaciallakes AT mrsiegfried entrainedwaterinbasalicesuppressesradarbedechopoweratactivesubglaciallakes AT dmschroeder entrainedwaterinbasalicesuppressesradarbedechopoweratactivesubglaciallakes |