Reorganisation of subglacial drainage processes during rapid melting of the Fennoscandian Ice Sheet
Unknown basal characteristics limit our ability to simulate the subglacial hydrology of rapidly thinning contemporary ice sheets. Subglacial water is typically conceptualised as being routed through either distributed, inefficient, and high pressure systems, or channelised, efficient, and low-pressu...
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Copernicus Publications
2023
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ftnonlinearchiv:oai:noa.gwlb.de:cop_mods_00069317 2023-11-12T04:17:03+01:00 Reorganisation of subglacial drainage processes during rapid melting of the Fennoscandian Ice Sheet Hepburn, Adam Jake Dow, Christine F. Ojala, Antti Mäkinen, Joni Ahokangas, Elina Hovikoski, Jussi Palmu, Jukka-Pekka Kajuutti, Kari 2023-10 electronic https://doi.org/10.5194/egusphere-2023-2141 https://noa.gwlb.de/receive/cop_mods_00069317 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00067704/egusphere-2023-2141.pdf https://egusphere.copernicus.org/preprints/2023/egusphere-2023-2141/egusphere-2023-2141.pdf eng eng Copernicus Publications https://doi.org/10.5194/egusphere-2023-2141 https://noa.gwlb.de/receive/cop_mods_00069317 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00067704/egusphere-2023-2141.pdf https://egusphere.copernicus.org/preprints/2023/egusphere-2023-2141/egusphere-2023-2141.pdf https://creativecommons.org/licenses/by/4.0/ uneingeschränkt info:eu-repo/semantics/openAccess article Verlagsveröffentlichung article Text doc-type:article 2023 ftnonlinearchiv https://doi.org/10.5194/egusphere-2023-2141 2023-10-22T23:22:31Z Unknown basal characteristics limit our ability to simulate the subglacial hydrology of rapidly thinning contemporary ice sheets. Subglacial water is typically conceptualised as being routed through either distributed, inefficient, and high pressure systems, or channelised, efficient, and low-pressure systems, transitioning between the two as a function of discharge. Sediment-based landforms generated beneath Pleistocene ice sheets, together with detailed digital elevation models, offer a valuable means of parameterising and testing models of subglacial hydrology. However, previous work using geomorphology to inform modelling has concentrated on landforms relating to channelised drainage (e.g., eskers) while using inherently channelised models unable to capture transitions in drainage state. Landscapes relating to the distributed drainage system, and the hypothesised transitional zone of drainage between distributed and channelised drainage modes have therefore been largely ignored. To address this, we use the Glacier Drainage System model (GlaDS), a 2D finite element model capable of capturing the transition between distributed and channelised drainage, to explore the genesis of ‘murtoos’, a distinctive triangular landform found in murtoo fields throughout Finland and Sweden. Murtoos are hypothesised to form 40–60 km from the former Fennoscandian ice margin at the onset of channelised drainage where water pressure is at or exceeds ice overburden pressure. Concentrating within a specific ice lobe of the former Fennoscandian Ice Sheet and parameterised using digital elevation models with a simulated former ice surface geometry, we carried out a range of sensitivity testing to explore murtoo genesis and drainage transitions beneath the palaeo ice sheet. Our modelling supports many of the predictions for murtoo origin, including the location of water pressures equal to ice overburden, the onset of channelised drainage, and the predicted water depths in terrain surrounding murtoo fields. Modelled channels also ... Article in Journal/Newspaper Fennoscandian Ice Sheet Niedersächsisches Online-Archiv NOA |
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English |
topic |
article Verlagsveröffentlichung |
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article Verlagsveröffentlichung Hepburn, Adam Jake Dow, Christine F. Ojala, Antti Mäkinen, Joni Ahokangas, Elina Hovikoski, Jussi Palmu, Jukka-Pekka Kajuutti, Kari Reorganisation of subglacial drainage processes during rapid melting of the Fennoscandian Ice Sheet |
topic_facet |
article Verlagsveröffentlichung |
description |
Unknown basal characteristics limit our ability to simulate the subglacial hydrology of rapidly thinning contemporary ice sheets. Subglacial water is typically conceptualised as being routed through either distributed, inefficient, and high pressure systems, or channelised, efficient, and low-pressure systems, transitioning between the two as a function of discharge. Sediment-based landforms generated beneath Pleistocene ice sheets, together with detailed digital elevation models, offer a valuable means of parameterising and testing models of subglacial hydrology. However, previous work using geomorphology to inform modelling has concentrated on landforms relating to channelised drainage (e.g., eskers) while using inherently channelised models unable to capture transitions in drainage state. Landscapes relating to the distributed drainage system, and the hypothesised transitional zone of drainage between distributed and channelised drainage modes have therefore been largely ignored. To address this, we use the Glacier Drainage System model (GlaDS), a 2D finite element model capable of capturing the transition between distributed and channelised drainage, to explore the genesis of ‘murtoos’, a distinctive triangular landform found in murtoo fields throughout Finland and Sweden. Murtoos are hypothesised to form 40–60 km from the former Fennoscandian ice margin at the onset of channelised drainage where water pressure is at or exceeds ice overburden pressure. Concentrating within a specific ice lobe of the former Fennoscandian Ice Sheet and parameterised using digital elevation models with a simulated former ice surface geometry, we carried out a range of sensitivity testing to explore murtoo genesis and drainage transitions beneath the palaeo ice sheet. Our modelling supports many of the predictions for murtoo origin, including the location of water pressures equal to ice overburden, the onset of channelised drainage, and the predicted water depths in terrain surrounding murtoo fields. Modelled channels also ... |
format |
Article in Journal/Newspaper |
author |
Hepburn, Adam Jake Dow, Christine F. Ojala, Antti Mäkinen, Joni Ahokangas, Elina Hovikoski, Jussi Palmu, Jukka-Pekka Kajuutti, Kari |
author_facet |
Hepburn, Adam Jake Dow, Christine F. Ojala, Antti Mäkinen, Joni Ahokangas, Elina Hovikoski, Jussi Palmu, Jukka-Pekka Kajuutti, Kari |
author_sort |
Hepburn, Adam Jake |
title |
Reorganisation of subglacial drainage processes during rapid melting of the Fennoscandian Ice Sheet |
title_short |
Reorganisation of subglacial drainage processes during rapid melting of the Fennoscandian Ice Sheet |
title_full |
Reorganisation of subglacial drainage processes during rapid melting of the Fennoscandian Ice Sheet |
title_fullStr |
Reorganisation of subglacial drainage processes during rapid melting of the Fennoscandian Ice Sheet |
title_full_unstemmed |
Reorganisation of subglacial drainage processes during rapid melting of the Fennoscandian Ice Sheet |
title_sort |
reorganisation of subglacial drainage processes during rapid melting of the fennoscandian ice sheet |
publisher |
Copernicus Publications |
publishDate |
2023 |
url |
https://doi.org/10.5194/egusphere-2023-2141 https://noa.gwlb.de/receive/cop_mods_00069317 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00067704/egusphere-2023-2141.pdf https://egusphere.copernicus.org/preprints/2023/egusphere-2023-2141/egusphere-2023-2141.pdf |
genre |
Fennoscandian Ice Sheet |
genre_facet |
Fennoscandian Ice Sheet |
op_relation |
https://doi.org/10.5194/egusphere-2023-2141 https://noa.gwlb.de/receive/cop_mods_00069317 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00067704/egusphere-2023-2141.pdf https://egusphere.copernicus.org/preprints/2023/egusphere-2023-2141/egusphere-2023-2141.pdf |
op_rights |
https://creativecommons.org/licenses/by/4.0/ uneingeschränkt info:eu-repo/semantics/openAccess |
op_doi |
https://doi.org/10.5194/egusphere-2023-2141 |
_version_ |
1782334048151011328 |