Tidal pressurization of the ocean cavity near an Antarctic ice shelf grounding line
Mass loss from the Antarctic ice sheet is sensitive to conditions in ice shelf grounding zones, the transition between grounded and floating ice. To observe tidal dynamics in the grounding zone, we moored an ocean pressure sensor to Ross Ice Shelf, recording data for 54days. In this region the ice s...
Published in: | Journal of Geophysical Research: Oceans |
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2020
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Online Access: | https://doi.org/10.1029/2019JC015562 http://ecite.utas.edu.au/138280 |
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ftunivtasecite:oai:ecite.utas.edu.au:138280 2023-05-15T13:42:40+02:00 Tidal pressurization of the ocean cavity near an Antarctic ice shelf grounding line Begeman, CB Tulaczyk, S Padman, L King, M Siegfried, MR Hodson, TO Fricker, HA 2020 https://doi.org/10.1029/2019JC015562 http://ecite.utas.edu.au/138280 en eng Wiley-Blackwell Publishing Ltd http://dx.doi.org/10.1029/2019JC015562 Begeman, CB and Tulaczyk, S and Padman, L and King, M and Siegfried, MR and Hodson, TO and Fricker, HA, Tidal pressurization of the ocean cavity near an Antarctic ice shelf grounding line, Journal of Geophysical Research: Oceans, 125, (4) Article e2019JC015562. ISSN 2169-9291 (2020) [Refereed Article] http://ecite.utas.edu.au/138280 Earth Sciences Physical geography and environmental geoscience Glaciology Refereed Article PeerReviewed 2020 ftunivtasecite https://doi.org/10.1029/2019JC015562 2022-08-29T22:17:53Z Mass loss from the Antarctic ice sheet is sensitive to conditions in ice shelf grounding zones, the transition between grounded and floating ice. To observe tidal dynamics in the grounding zone, we moored an ocean pressure sensor to Ross Ice Shelf, recording data for 54days. In this region the ice shelf is brought out of hydrostatic equilibrium by the flexural rigidity of ice, yet we found that tidal pressure variations at a constant geopotential surface were similar within and outside of the grounding zone. This implies that the grounding zone ocean cavity was overpressurized at high tide and underpressurized at low tide by up to 10kPa with respect to glaciostatic pressure at the ice shelf base. Phase lags between ocean pressure and vertical ice shelf motion were tens of minutes for diurnal and semidiurnal tides, an effect that has not been incorporated into ocean models of tidal currents below ice shelves. These tidal pressure variations may affect the production and export of meltwater in the subglacial environment and may increase basal crevasse heights in the grounding zone by several meters, according to linear elastic fracture mechanics. We find anomalously high tidal energy loss at the K 1 constituent in the grounding zone and hypothesize that this could be explained by seawater injection into the subglacial environment at high tide or internal tide generation through interactions with topography. These observations lay the foundation for improved representation of the grounding zone and its tidal dynamics in ocean circulation models of subice shelf cavities. Article in Journal/Newspaper Antarc* Antarctic Ice Sheet Ice Shelf Ice Shelves Ross Ice Shelf eCite UTAS (University of Tasmania) Antarctic Ross Ice Shelf The Antarctic Journal of Geophysical Research: Oceans 125 4 |
institution |
Open Polar |
collection |
eCite UTAS (University of Tasmania) |
op_collection_id |
ftunivtasecite |
language |
English |
topic |
Earth Sciences Physical geography and environmental geoscience Glaciology |
spellingShingle |
Earth Sciences Physical geography and environmental geoscience Glaciology Begeman, CB Tulaczyk, S Padman, L King, M Siegfried, MR Hodson, TO Fricker, HA Tidal pressurization of the ocean cavity near an Antarctic ice shelf grounding line |
topic_facet |
Earth Sciences Physical geography and environmental geoscience Glaciology |
description |
Mass loss from the Antarctic ice sheet is sensitive to conditions in ice shelf grounding zones, the transition between grounded and floating ice. To observe tidal dynamics in the grounding zone, we moored an ocean pressure sensor to Ross Ice Shelf, recording data for 54days. In this region the ice shelf is brought out of hydrostatic equilibrium by the flexural rigidity of ice, yet we found that tidal pressure variations at a constant geopotential surface were similar within and outside of the grounding zone. This implies that the grounding zone ocean cavity was overpressurized at high tide and underpressurized at low tide by up to 10kPa with respect to glaciostatic pressure at the ice shelf base. Phase lags between ocean pressure and vertical ice shelf motion were tens of minutes for diurnal and semidiurnal tides, an effect that has not been incorporated into ocean models of tidal currents below ice shelves. These tidal pressure variations may affect the production and export of meltwater in the subglacial environment and may increase basal crevasse heights in the grounding zone by several meters, according to linear elastic fracture mechanics. We find anomalously high tidal energy loss at the K 1 constituent in the grounding zone and hypothesize that this could be explained by seawater injection into the subglacial environment at high tide or internal tide generation through interactions with topography. These observations lay the foundation for improved representation of the grounding zone and its tidal dynamics in ocean circulation models of subice shelf cavities. |
format |
Article in Journal/Newspaper |
author |
Begeman, CB Tulaczyk, S Padman, L King, M Siegfried, MR Hodson, TO Fricker, HA |
author_facet |
Begeman, CB Tulaczyk, S Padman, L King, M Siegfried, MR Hodson, TO Fricker, HA |
author_sort |
Begeman, CB |
title |
Tidal pressurization of the ocean cavity near an Antarctic ice shelf grounding line |
title_short |
Tidal pressurization of the ocean cavity near an Antarctic ice shelf grounding line |
title_full |
Tidal pressurization of the ocean cavity near an Antarctic ice shelf grounding line |
title_fullStr |
Tidal pressurization of the ocean cavity near an Antarctic ice shelf grounding line |
title_full_unstemmed |
Tidal pressurization of the ocean cavity near an Antarctic ice shelf grounding line |
title_sort |
tidal pressurization of the ocean cavity near an antarctic ice shelf grounding line |
publisher |
Wiley-Blackwell Publishing Ltd |
publishDate |
2020 |
url |
https://doi.org/10.1029/2019JC015562 http://ecite.utas.edu.au/138280 |
geographic |
Antarctic Ross Ice Shelf The Antarctic |
geographic_facet |
Antarctic Ross Ice Shelf The Antarctic |
genre |
Antarc* Antarctic Ice Sheet Ice Shelf Ice Shelves Ross Ice Shelf |
genre_facet |
Antarc* Antarctic Ice Sheet Ice Shelf Ice Shelves Ross Ice Shelf |
op_relation |
http://dx.doi.org/10.1029/2019JC015562 Begeman, CB and Tulaczyk, S and Padman, L and King, M and Siegfried, MR and Hodson, TO and Fricker, HA, Tidal pressurization of the ocean cavity near an Antarctic ice shelf grounding line, Journal of Geophysical Research: Oceans, 125, (4) Article e2019JC015562. ISSN 2169-9291 (2020) [Refereed Article] http://ecite.utas.edu.au/138280 |
op_doi |
https://doi.org/10.1029/2019JC015562 |
container_title |
Journal of Geophysical Research: Oceans |
container_volume |
125 |
container_issue |
4 |
_version_ |
1766171124454916096 |