Subglacial permafrost dynamics and erosion inside subglacial channels driven by surface events in Svalbard

Cold glacier beds, i.e., where the ice is frozen to its base, are widespread in polar regions. Common theories state that stable permafrost should exist under glacier beds on shorter timescales, varying from years to decades. Presently, only a few direct measurements of both subglacial permafrost an...

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Published in:The Cryosphere
Main Authors: A. Alexander, J. Obu, T. V. Schuler, A. Kääb, H. H. Christiansen
Format: Article in Journal/Newspaper
Language:English
Published: Copernicus Publications 2020
Subjects:
geo
Ice
Online Access:https://doi.org/10.5194/tc-14-4217-2020
https://tc.copernicus.org/articles/14/4217/2020/tc-14-4217-2020.pdf
https://doaj.org/article/8f4a63597a80448d9556f2781bf5eefd
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record_format openpolar
spelling fttriple:oai:gotriple.eu:oai:doaj.org/article:8f4a63597a80448d9556f2781bf5eefd 2023-05-15T16:22:11+02:00 Subglacial permafrost dynamics and erosion inside subglacial channels driven by surface events in Svalbard A. Alexander J. Obu T. V. Schuler A. Kääb H. H. Christiansen 2020-11-01 https://doi.org/10.5194/tc-14-4217-2020 https://tc.copernicus.org/articles/14/4217/2020/tc-14-4217-2020.pdf https://doaj.org/article/8f4a63597a80448d9556f2781bf5eefd en eng Copernicus Publications doi:10.5194/tc-14-4217-2020 1994-0416 1994-0424 https://tc.copernicus.org/articles/14/4217/2020/tc-14-4217-2020.pdf https://doaj.org/article/8f4a63597a80448d9556f2781bf5eefd undefined The Cryosphere, Vol 14, Pp 4217-4231 (2020) geo envir Journal Article https://vocabularies.coar-repositories.org/resource_types/c_6501/ 2020 fttriple https://doi.org/10.5194/tc-14-4217-2020 2023-01-22T17:53:07Z Cold glacier beds, i.e., where the ice is frozen to its base, are widespread in polar regions. Common theories state that stable permafrost should exist under glacier beds on shorter timescales, varying from years to decades. Presently, only a few direct measurements of both subglacial permafrost and the processes influencing its thermal regime exist. Here, we present subglacial permafrost and active layer measurements obtained from within the basal drainage systems of two cold-based glaciers on Svalbard during the summer melt season. Temperature observations were obtained from subglacial sediment that was accessed through the drainage systems of the two glaciers in the previous winters. The temperature records cover the periods from spring to autumn in 2016 and 2019 at the glaciers Larsbreen and Tellbreen in central Svalbard. The ground temperature below Larsbreen indicates colder ground conditions, whereas the temperatures of the Tellbreen drainage system show considerably warmer conditions, close to the freezing point. We suggest the latter is due to the presence of liquid water all year round inside the Tellbreen drainage system. Both drainage systems investigated show an increase in subglacial sediment temperatures after the disappearance of snow bridges and the subsequent connection to surface meltwater supply at the start of the summer melt season. Temperature records show influence of sudden summer water supply events, when heavy melt and rain left their signatures on the thermal regime and the erosion of the glacier bed. Observed vertical erosion can reach up to 0.9 m d−1 at the base of basal drainage channels during summer. We also show that the thermal regime under the subglacial drainage systems is not stable during summer but experiences several freeze–thaw cycles driven by weather events. Our results show the direct importance of heavy melt events and rain on the thermal regime of subglacial permafrost and the erosion of the glacier bed in the vicinity of subglacial drainage channels. Increased ... Article in Journal/Newspaper glacier Ice permafrost Svalbard The Cryosphere Unknown Larsbreen ENVELOPE(15.567,15.567,78.183,78.183) Svalbard Tellbreen ENVELOPE(16.217,16.217,78.250,78.250) The Cryosphere 14 11 4217 4231
institution Open Polar
collection Unknown
op_collection_id fttriple
language English
topic geo
envir
spellingShingle geo
envir
A. Alexander
J. Obu
T. V. Schuler
A. Kääb
H. H. Christiansen
Subglacial permafrost dynamics and erosion inside subglacial channels driven by surface events in Svalbard
topic_facet geo
envir
description Cold glacier beds, i.e., where the ice is frozen to its base, are widespread in polar regions. Common theories state that stable permafrost should exist under glacier beds on shorter timescales, varying from years to decades. Presently, only a few direct measurements of both subglacial permafrost and the processes influencing its thermal regime exist. Here, we present subglacial permafrost and active layer measurements obtained from within the basal drainage systems of two cold-based glaciers on Svalbard during the summer melt season. Temperature observations were obtained from subglacial sediment that was accessed through the drainage systems of the two glaciers in the previous winters. The temperature records cover the periods from spring to autumn in 2016 and 2019 at the glaciers Larsbreen and Tellbreen in central Svalbard. The ground temperature below Larsbreen indicates colder ground conditions, whereas the temperatures of the Tellbreen drainage system show considerably warmer conditions, close to the freezing point. We suggest the latter is due to the presence of liquid water all year round inside the Tellbreen drainage system. Both drainage systems investigated show an increase in subglacial sediment temperatures after the disappearance of snow bridges and the subsequent connection to surface meltwater supply at the start of the summer melt season. Temperature records show influence of sudden summer water supply events, when heavy melt and rain left their signatures on the thermal regime and the erosion of the glacier bed. Observed vertical erosion can reach up to 0.9 m d−1 at the base of basal drainage channels during summer. We also show that the thermal regime under the subglacial drainage systems is not stable during summer but experiences several freeze–thaw cycles driven by weather events. Our results show the direct importance of heavy melt events and rain on the thermal regime of subglacial permafrost and the erosion of the glacier bed in the vicinity of subglacial drainage channels. Increased ...
format Article in Journal/Newspaper
author A. Alexander
J. Obu
T. V. Schuler
A. Kääb
H. H. Christiansen
author_facet A. Alexander
J. Obu
T. V. Schuler
A. Kääb
H. H. Christiansen
author_sort A. Alexander
title Subglacial permafrost dynamics and erosion inside subglacial channels driven by surface events in Svalbard
title_short Subglacial permafrost dynamics and erosion inside subglacial channels driven by surface events in Svalbard
title_full Subglacial permafrost dynamics and erosion inside subglacial channels driven by surface events in Svalbard
title_fullStr Subglacial permafrost dynamics and erosion inside subglacial channels driven by surface events in Svalbard
title_full_unstemmed Subglacial permafrost dynamics and erosion inside subglacial channels driven by surface events in Svalbard
title_sort subglacial permafrost dynamics and erosion inside subglacial channels driven by surface events in svalbard
publisher Copernicus Publications
publishDate 2020
url https://doi.org/10.5194/tc-14-4217-2020
https://tc.copernicus.org/articles/14/4217/2020/tc-14-4217-2020.pdf
https://doaj.org/article/8f4a63597a80448d9556f2781bf5eefd
long_lat ENVELOPE(15.567,15.567,78.183,78.183)
ENVELOPE(16.217,16.217,78.250,78.250)
geographic Larsbreen
Svalbard
Tellbreen
geographic_facet Larsbreen
Svalbard
Tellbreen
genre glacier
Ice
permafrost
Svalbard
The Cryosphere
genre_facet glacier
Ice
permafrost
Svalbard
The Cryosphere
op_source The Cryosphere, Vol 14, Pp 4217-4231 (2020)
op_relation doi:10.5194/tc-14-4217-2020
1994-0416
1994-0424
https://tc.copernicus.org/articles/14/4217/2020/tc-14-4217-2020.pdf
https://doaj.org/article/8f4a63597a80448d9556f2781bf5eefd
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op_doi https://doi.org/10.5194/tc-14-4217-2020
container_title The Cryosphere
container_volume 14
container_issue 11
container_start_page 4217
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