A quantitative method for deriving salinity of subglacial water using ground-based transient electromagnetics
Liquid water can exist at temperatures well below freezing beneath glaciers and ice sheets, where subglacial water systems, fresh and saline, have been shown to host unique microbial ecosystems. Geophysical techniques sensitive to fluid-content contrasts, e.g. electromagnetics, can characterize subg...
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Cambridge University Press
2022
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Online Access: | https://doi.org/10.1017/jog.2021.94 https://doaj.org/article/941b44f5b1314a33aab57c24e82c16b0 |
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ftdoajarticles:oai:doaj.org/article:941b44f5b1314a33aab57c24e82c16b0 2023-05-15T16:57:33+02:00 A quantitative method for deriving salinity of subglacial water using ground-based transient electromagnetics Siobhan F. Killingbeck Christine F. Dow Martyn J. Unsworth 2022-04-01T00:00:00Z https://doi.org/10.1017/jog.2021.94 https://doaj.org/article/941b44f5b1314a33aab57c24e82c16b0 EN eng Cambridge University Press https://www.cambridge.org/core/product/identifier/S0022143021000940/type/journal_article https://doaj.org/toc/0022-1430 https://doaj.org/toc/1727-5652 doi:10.1017/jog.2021.94 0022-1430 1727-5652 https://doaj.org/article/941b44f5b1314a33aab57c24e82c16b0 Journal of Glaciology, Vol 68, Pp 319-336 (2022) Salinity subglacial lake subglacial water transient electromagnetics Environmental sciences GE1-350 Meteorology. Climatology QC851-999 article 2022 ftdoajarticles https://doi.org/10.1017/jog.2021.94 2023-03-12T01:30:54Z Liquid water can exist at temperatures well below freezing beneath glaciers and ice sheets, where subglacial water systems, fresh and saline, have been shown to host unique microbial ecosystems. Geophysical techniques sensitive to fluid-content contrasts, e.g. electromagnetics, can characterize subglacial water and its salinity. Here, we assess the ground-based transient electromagnetic (TEM) method for deriving the resistivity and salinity of subglacial water. We adapt an existing open-source Bayesian inversion algorithm, which uses independent depth constraints, to output posterior distributions of resistivity and pore fluid salinity with depth. A variety of synthetic models, including a thin (5 m), conductive (0.16 Ωm), hypersaline (147 psu) subglacial lake, are used to evaluate the TEM method for imaging under 800 m-thick ice. The study demonstrates that TEM methods can resolve conductive, saline bodies accurately using external depth constraints, for example, from radar or seismic data. The depth resolution of TEM can be limited beneath deep (>800 m), thick (>50 m) conductive, water bodies and additional constraints from passive electromagnetic (EM) methods could be used to reduce ambiguities in the TEM results. Subsequently, non-invasive active and passive EM methods could provide profound insights into remote aqueous systems under glaciers and ice sheets. Article in Journal/Newspaper Journal of Glaciology Directory of Open Access Journals: DOAJ Articles Journal of Glaciology 68 268 319 336 |
institution |
Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
Salinity subglacial lake subglacial water transient electromagnetics Environmental sciences GE1-350 Meteorology. Climatology QC851-999 |
spellingShingle |
Salinity subglacial lake subglacial water transient electromagnetics Environmental sciences GE1-350 Meteorology. Climatology QC851-999 Siobhan F. Killingbeck Christine F. Dow Martyn J. Unsworth A quantitative method for deriving salinity of subglacial water using ground-based transient electromagnetics |
topic_facet |
Salinity subglacial lake subglacial water transient electromagnetics Environmental sciences GE1-350 Meteorology. Climatology QC851-999 |
description |
Liquid water can exist at temperatures well below freezing beneath glaciers and ice sheets, where subglacial water systems, fresh and saline, have been shown to host unique microbial ecosystems. Geophysical techniques sensitive to fluid-content contrasts, e.g. electromagnetics, can characterize subglacial water and its salinity. Here, we assess the ground-based transient electromagnetic (TEM) method for deriving the resistivity and salinity of subglacial water. We adapt an existing open-source Bayesian inversion algorithm, which uses independent depth constraints, to output posterior distributions of resistivity and pore fluid salinity with depth. A variety of synthetic models, including a thin (5 m), conductive (0.16 Ωm), hypersaline (147 psu) subglacial lake, are used to evaluate the TEM method for imaging under 800 m-thick ice. The study demonstrates that TEM methods can resolve conductive, saline bodies accurately using external depth constraints, for example, from radar or seismic data. The depth resolution of TEM can be limited beneath deep (>800 m), thick (>50 m) conductive, water bodies and additional constraints from passive electromagnetic (EM) methods could be used to reduce ambiguities in the TEM results. Subsequently, non-invasive active and passive EM methods could provide profound insights into remote aqueous systems under glaciers and ice sheets. |
format |
Article in Journal/Newspaper |
author |
Siobhan F. Killingbeck Christine F. Dow Martyn J. Unsworth |
author_facet |
Siobhan F. Killingbeck Christine F. Dow Martyn J. Unsworth |
author_sort |
Siobhan F. Killingbeck |
title |
A quantitative method for deriving salinity of subglacial water using ground-based transient electromagnetics |
title_short |
A quantitative method for deriving salinity of subglacial water using ground-based transient electromagnetics |
title_full |
A quantitative method for deriving salinity of subglacial water using ground-based transient electromagnetics |
title_fullStr |
A quantitative method for deriving salinity of subglacial water using ground-based transient electromagnetics |
title_full_unstemmed |
A quantitative method for deriving salinity of subglacial water using ground-based transient electromagnetics |
title_sort |
quantitative method for deriving salinity of subglacial water using ground-based transient electromagnetics |
publisher |
Cambridge University Press |
publishDate |
2022 |
url |
https://doi.org/10.1017/jog.2021.94 https://doaj.org/article/941b44f5b1314a33aab57c24e82c16b0 |
genre |
Journal of Glaciology |
genre_facet |
Journal of Glaciology |
op_source |
Journal of Glaciology, Vol 68, Pp 319-336 (2022) |
op_relation |
https://www.cambridge.org/core/product/identifier/S0022143021000940/type/journal_article https://doaj.org/toc/0022-1430 https://doaj.org/toc/1727-5652 doi:10.1017/jog.2021.94 0022-1430 1727-5652 https://doaj.org/article/941b44f5b1314a33aab57c24e82c16b0 |
op_doi |
https://doi.org/10.1017/jog.2021.94 |
container_title |
Journal of Glaciology |
container_volume |
68 |
container_issue |
268 |
container_start_page |
319 |
op_container_end_page |
336 |
_version_ |
1766049121328693248 |