Hydraulic suppression of basal glacier melt in sill fjords
We examine how hydraulically-controlled exchange flows in silled fjords affect the relationship between basal glacier melt and features of warm intermediate Atlantic Water (AW) outside the fjords. Using theory and an ocean-circulation model, we show that an exchange flow can be forced to transit int...
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2023
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ftgfzpotsdam:oai:gfzpublic.gfz-potsdam.de:item_5020483 2023-07-30T04:03:37+02:00 Hydraulic suppression of basal glacier melt in sill fjords Nilsson, J. 2023-07-11 https://gfzpublic.gfz-potsdam.de/pubman/item/item_5020483 eng eng info:eu-repo/semantics/altIdentifier/doi/10.57757/IUGG23-3027 https://gfzpublic.gfz-potsdam.de/pubman/item/item_5020483 XXVIII General Assembly of the International Union of Geodesy and Geophysics (IUGG) info:eu-repo/semantics/conferenceObject 2023 ftgfzpotsdam https://doi.org/10.57757/IUGG23-3027 2023-07-09T23:40:17Z We examine how hydraulically-controlled exchange flows in silled fjords affect the relationship between basal glacier melt and features of warm intermediate Atlantic Water (AW) outside the fjords. Using theory and an ocean-circulation model, we show that an exchange flow can be forced to transit into a hydraulic regime if the AW interface height decreases, the AW temperature increases, or the production of glacially modified water is boosted by subglacial discharge. In the hydraulic regime, the heat transport across the sill becomes a rate limiting factor for the basal melt, which is suppressed. An interplay between processes near the ice--ocean boundary and the hydraulically-controlled exchange flow determines the melt dynamics, and the sensitivity of the basal melt to changes of the AW temperature is reduced. The model results are discussed in relation to observations from Ryder, Petermann, and 79$^{\circ}$N glaciers in North Greenland. We also outline how hydraulic suppression of basal melt can be represented in ice sheet modelling. Conference Object glacier Greenland Ice Sheet North Greenland GFZpublic (German Research Centre for Geosciences, Helmholtz-Zentrum Potsdam) Greenland Ryder ENVELOPE(-68.333,-68.333,-67.566,-67.566) |
institution |
Open Polar |
collection |
GFZpublic (German Research Centre for Geosciences, Helmholtz-Zentrum Potsdam) |
op_collection_id |
ftgfzpotsdam |
language |
English |
description |
We examine how hydraulically-controlled exchange flows in silled fjords affect the relationship between basal glacier melt and features of warm intermediate Atlantic Water (AW) outside the fjords. Using theory and an ocean-circulation model, we show that an exchange flow can be forced to transit into a hydraulic regime if the AW interface height decreases, the AW temperature increases, or the production of glacially modified water is boosted by subglacial discharge. In the hydraulic regime, the heat transport across the sill becomes a rate limiting factor for the basal melt, which is suppressed. An interplay between processes near the ice--ocean boundary and the hydraulically-controlled exchange flow determines the melt dynamics, and the sensitivity of the basal melt to changes of the AW temperature is reduced. The model results are discussed in relation to observations from Ryder, Petermann, and 79$^{\circ}$N glaciers in North Greenland. We also outline how hydraulic suppression of basal melt can be represented in ice sheet modelling. |
format |
Conference Object |
author |
Nilsson, J. |
spellingShingle |
Nilsson, J. Hydraulic suppression of basal glacier melt in sill fjords |
author_facet |
Nilsson, J. |
author_sort |
Nilsson, J. |
title |
Hydraulic suppression of basal glacier melt in sill fjords |
title_short |
Hydraulic suppression of basal glacier melt in sill fjords |
title_full |
Hydraulic suppression of basal glacier melt in sill fjords |
title_fullStr |
Hydraulic suppression of basal glacier melt in sill fjords |
title_full_unstemmed |
Hydraulic suppression of basal glacier melt in sill fjords |
title_sort |
hydraulic suppression of basal glacier melt in sill fjords |
publishDate |
2023 |
url |
https://gfzpublic.gfz-potsdam.de/pubman/item/item_5020483 |
long_lat |
ENVELOPE(-68.333,-68.333,-67.566,-67.566) |
geographic |
Greenland Ryder |
geographic_facet |
Greenland Ryder |
genre |
glacier Greenland Ice Sheet North Greenland |
genre_facet |
glacier Greenland Ice Sheet North Greenland |
op_source |
XXVIII General Assembly of the International Union of Geodesy and Geophysics (IUGG) |
op_relation |
info:eu-repo/semantics/altIdentifier/doi/10.57757/IUGG23-3027 https://gfzpublic.gfz-potsdam.de/pubman/item/item_5020483 |
op_doi |
https://doi.org/10.57757/IUGG23-3027 |
_version_ |
1772814654686363648 |