Multi-scale variations of hydro-mechanical conditions at the base of the surge-type glacier Kongsvegen, Svalbard
Fast glacier flow and dynamic instabilities, such as surges, are primarily caused by changes at the ice-bed interface, where basal slip and sediment deformation drive basal glacier motion. Determining subglacial conditions and their responses to hydraulic forcing (e.g. rainfall, surface melt) remain...
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ftcopernicus:oai:publications.copernicus.org:egusphere110528 2023-06-06T11:51:30+02:00 Multi-scale variations of hydro-mechanical conditions at the base of the surge-type glacier Kongsvegen, Svalbard Bouchayer, Coline Nanni, Ugo Lefeuvre, Pierre-Marie Hulth, John Steffensen Schmidt, Louise Kohler, Jack Renard, François Schuler, Thomas V. 2023-04-12 application/pdf https://doi.org/10.5194/egusphere-2023-618 https://egusphere.copernicus.org/preprints/2023/egusphere-2023-618/ eng eng doi:10.5194/egusphere-2023-618 https://egusphere.copernicus.org/preprints/2023/egusphere-2023-618/ eISSN: Text 2023 ftcopernicus https://doi.org/10.5194/egusphere-2023-618 2023-04-17T16:23:12Z Fast glacier flow and dynamic instabilities, such as surges, are primarily caused by changes at the ice-bed interface, where basal slip and sediment deformation drive basal glacier motion. Determining subglacial conditions and their responses to hydraulic forcing (e.g. rainfall, surface melt) remains challenging due to the difficulty of accessing the glacier bed. In this study, we monitor the interplay between surface runoff and hydro-mechanical conditions at the base of the Arctic surge-type glacier Kongsvegen, in Svalbard, over two contrasting melt seasons. Kongsvegen last surged in 1948, after which it entered a prolonged quiescent phase. Around 2014, flow speeds began to increase, sign of an imminent new fast-flow event. In 2021 we instrumented a borehole to assess subglacial conditions at the local scale and deployed seismometers to monitor the subglacial conditions at the kilometer scale. We measure both subglacial water pressure within the borehole with a water pressure sensor and till rheology with a ploughmeter inserted into the sediments at the bottom of the borehole. We use channel-flow-induced tremors recorded by a seismometer to characterize hydraulic conditions over a kilometre scale at the base of the glacier. The records cover the period from spring 2021 until summer 2022. To characterize the variations in the subglacial conditions caused by changes in surface runoff, we investigate the phase relationship (i.e. how two variables evolve in time) of the following hydro-mechanical condition proxies: water pressure, hydraulic gradient, hydraulic radius, and sediment ploughing forces. We analyse these proxies versus modelled runoff analyzed over seasonal, multi-day and diurnal time-scales. We compare our results with existing theories in terms of subglacial drainage system evolution and sediment shear strength to describe various aspects of subglacial conditions. We find apparent ambiguities in the interpretation of different variables recorded by individual sensors, thus demonstrating the importance ... Text Arctic glacier Svalbard Copernicus Publications: E-Journals Arctic Kongsvegen ENVELOPE(12.657,12.657,78.854,78.854) Svalbard |
institution |
Open Polar |
collection |
Copernicus Publications: E-Journals |
op_collection_id |
ftcopernicus |
language |
English |
description |
Fast glacier flow and dynamic instabilities, such as surges, are primarily caused by changes at the ice-bed interface, where basal slip and sediment deformation drive basal glacier motion. Determining subglacial conditions and their responses to hydraulic forcing (e.g. rainfall, surface melt) remains challenging due to the difficulty of accessing the glacier bed. In this study, we monitor the interplay between surface runoff and hydro-mechanical conditions at the base of the Arctic surge-type glacier Kongsvegen, in Svalbard, over two contrasting melt seasons. Kongsvegen last surged in 1948, after which it entered a prolonged quiescent phase. Around 2014, flow speeds began to increase, sign of an imminent new fast-flow event. In 2021 we instrumented a borehole to assess subglacial conditions at the local scale and deployed seismometers to monitor the subglacial conditions at the kilometer scale. We measure both subglacial water pressure within the borehole with a water pressure sensor and till rheology with a ploughmeter inserted into the sediments at the bottom of the borehole. We use channel-flow-induced tremors recorded by a seismometer to characterize hydraulic conditions over a kilometre scale at the base of the glacier. The records cover the period from spring 2021 until summer 2022. To characterize the variations in the subglacial conditions caused by changes in surface runoff, we investigate the phase relationship (i.e. how two variables evolve in time) of the following hydro-mechanical condition proxies: water pressure, hydraulic gradient, hydraulic radius, and sediment ploughing forces. We analyse these proxies versus modelled runoff analyzed over seasonal, multi-day and diurnal time-scales. We compare our results with existing theories in terms of subglacial drainage system evolution and sediment shear strength to describe various aspects of subglacial conditions. We find apparent ambiguities in the interpretation of different variables recorded by individual sensors, thus demonstrating the importance ... |
format |
Text |
author |
Bouchayer, Coline Nanni, Ugo Lefeuvre, Pierre-Marie Hulth, John Steffensen Schmidt, Louise Kohler, Jack Renard, François Schuler, Thomas V. |
spellingShingle |
Bouchayer, Coline Nanni, Ugo Lefeuvre, Pierre-Marie Hulth, John Steffensen Schmidt, Louise Kohler, Jack Renard, François Schuler, Thomas V. Multi-scale variations of hydro-mechanical conditions at the base of the surge-type glacier Kongsvegen, Svalbard |
author_facet |
Bouchayer, Coline Nanni, Ugo Lefeuvre, Pierre-Marie Hulth, John Steffensen Schmidt, Louise Kohler, Jack Renard, François Schuler, Thomas V. |
author_sort |
Bouchayer, Coline |
title |
Multi-scale variations of hydro-mechanical conditions at the base of the surge-type glacier Kongsvegen, Svalbard |
title_short |
Multi-scale variations of hydro-mechanical conditions at the base of the surge-type glacier Kongsvegen, Svalbard |
title_full |
Multi-scale variations of hydro-mechanical conditions at the base of the surge-type glacier Kongsvegen, Svalbard |
title_fullStr |
Multi-scale variations of hydro-mechanical conditions at the base of the surge-type glacier Kongsvegen, Svalbard |
title_full_unstemmed |
Multi-scale variations of hydro-mechanical conditions at the base of the surge-type glacier Kongsvegen, Svalbard |
title_sort |
multi-scale variations of hydro-mechanical conditions at the base of the surge-type glacier kongsvegen, svalbard |
publishDate |
2023 |
url |
https://doi.org/10.5194/egusphere-2023-618 https://egusphere.copernicus.org/preprints/2023/egusphere-2023-618/ |
long_lat |
ENVELOPE(12.657,12.657,78.854,78.854) |
geographic |
Arctic Kongsvegen Svalbard |
geographic_facet |
Arctic Kongsvegen Svalbard |
genre |
Arctic glacier Svalbard |
genre_facet |
Arctic glacier Svalbard |
op_source |
eISSN: |
op_relation |
doi:10.5194/egusphere-2023-618 https://egusphere.copernicus.org/preprints/2023/egusphere-2023-618/ |
op_doi |
https://doi.org/10.5194/egusphere-2023-618 |
_version_ |
1767957194115907584 |