Tidal modulation of buoyant flow and basal melt beneath Petermann Gletscher Ice Shelf, Greenland.
A set of collocated, in situ oceanographic and glaciological measurements from Petermann Gletscher Ice Shelf, Greenland, provides insights into the dynamics of under‐ice flow driving basal melting. At a site 16 km seaward of the grounding line within a longitudinal basal channel, two conductivity‐te...
Published in: | Journal of Geophysical Research: Oceans |
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American Geophysical Union
2020
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ftnerc:oai:nora.nerc.ac.uk:528633 2024-02-11T10:04:19+01:00 Tidal modulation of buoyant flow and basal melt beneath Petermann Gletscher Ice Shelf, Greenland. Washam, Peter Nicholls, Keith Muenchow, Andreas Padman, Laurie 2020-10-13 text http://nora.nerc.ac.uk/id/eprint/528633/ https://nora.nerc.ac.uk/id/eprint/528633/1/2020JC016427.pdf https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2020JC016427 en eng American Geophysical Union https://nora.nerc.ac.uk/id/eprint/528633/1/2020JC016427.pdf Washam, Peter; Nicholls, Keith orcid:0000-0002-2188-4509 Muenchow, Andreas; Padman, Laurie. 2020 Tidal modulation of buoyant flow and basal melt beneath Petermann Gletscher Ice Shelf, Greenland. Journal of Geophysical Research: Oceans, 125 (10), e2020JC016427. 19, pp. https://doi.org/10.1029/2020JC016427 <https://doi.org/10.1029/2020JC016427> cc_by_4 Publication - Article PeerReviewed 2020 ftnerc https://doi.org/10.1029/2020JC016427 2024-01-19T00:03:17Z A set of collocated, in situ oceanographic and glaciological measurements from Petermann Gletscher Ice Shelf, Greenland, provides insights into the dynamics of under‐ice flow driving basal melting. At a site 16 km seaward of the grounding line within a longitudinal basal channel, two conductivity‐temperature (CT) sensors beneath the ice base and a phase‐sensitive radar on the ice surface were used to monitor the coupled ice shelf‐ocean system. A six month time series spanning August 23, 2015 to February 12, 2016 exhibited two distinct periods of ice‐ocean interactions. Between August and December, radar‐derived basal melt rates featured fortnightly peaks of ~15 m yr‐1 which preceded the arrival of cold and fresh pulses in the ocean that had high concentrations of subglacial runoff and glacial meltwater. Estimated current speeds reached 0.20‐0.40 m s‐1 during these pulses, consistent with a strengthened meltwater plume from freshwater enrichment. Such signals did not occur between December and February, when ice‐ocean interactions instead varied at principal diurnal and semidiurnal tidal frequencies, and lower melt rates and current speeds prevailed. A combination of estimated current speeds and meltwater concentrations from the two CT sensors yields estimates of subglacial runoff and glacial meltwater volume fluxes that vary between 10 and 80 m3 s‐1 during the ocean pulses. Area‐average upstream ice shelf melt rates from these fluxes are up to 170 m yr‐1, revealing that these strengthened plumes had already driven their most intense melting before arriving at the study site. Article in Journal/Newspaper Greenland Ice Shelf Petermann gletscher Natural Environment Research Council: NERC Open Research Archive Greenland Petermann Gletscher ENVELOPE(-59.500,-59.500,80.500,80.500) Journal of Geophysical Research: Oceans 125 10 |
institution |
Open Polar |
collection |
Natural Environment Research Council: NERC Open Research Archive |
op_collection_id |
ftnerc |
language |
English |
description |
A set of collocated, in situ oceanographic and glaciological measurements from Petermann Gletscher Ice Shelf, Greenland, provides insights into the dynamics of under‐ice flow driving basal melting. At a site 16 km seaward of the grounding line within a longitudinal basal channel, two conductivity‐temperature (CT) sensors beneath the ice base and a phase‐sensitive radar on the ice surface were used to monitor the coupled ice shelf‐ocean system. A six month time series spanning August 23, 2015 to February 12, 2016 exhibited two distinct periods of ice‐ocean interactions. Between August and December, radar‐derived basal melt rates featured fortnightly peaks of ~15 m yr‐1 which preceded the arrival of cold and fresh pulses in the ocean that had high concentrations of subglacial runoff and glacial meltwater. Estimated current speeds reached 0.20‐0.40 m s‐1 during these pulses, consistent with a strengthened meltwater plume from freshwater enrichment. Such signals did not occur between December and February, when ice‐ocean interactions instead varied at principal diurnal and semidiurnal tidal frequencies, and lower melt rates and current speeds prevailed. A combination of estimated current speeds and meltwater concentrations from the two CT sensors yields estimates of subglacial runoff and glacial meltwater volume fluxes that vary between 10 and 80 m3 s‐1 during the ocean pulses. Area‐average upstream ice shelf melt rates from these fluxes are up to 170 m yr‐1, revealing that these strengthened plumes had already driven their most intense melting before arriving at the study site. |
format |
Article in Journal/Newspaper |
author |
Washam, Peter Nicholls, Keith Muenchow, Andreas Padman, Laurie |
spellingShingle |
Washam, Peter Nicholls, Keith Muenchow, Andreas Padman, Laurie Tidal modulation of buoyant flow and basal melt beneath Petermann Gletscher Ice Shelf, Greenland. |
author_facet |
Washam, Peter Nicholls, Keith Muenchow, Andreas Padman, Laurie |
author_sort |
Washam, Peter |
title |
Tidal modulation of buoyant flow and basal melt beneath Petermann Gletscher Ice Shelf, Greenland. |
title_short |
Tidal modulation of buoyant flow and basal melt beneath Petermann Gletscher Ice Shelf, Greenland. |
title_full |
Tidal modulation of buoyant flow and basal melt beneath Petermann Gletscher Ice Shelf, Greenland. |
title_fullStr |
Tidal modulation of buoyant flow and basal melt beneath Petermann Gletscher Ice Shelf, Greenland. |
title_full_unstemmed |
Tidal modulation of buoyant flow and basal melt beneath Petermann Gletscher Ice Shelf, Greenland. |
title_sort |
tidal modulation of buoyant flow and basal melt beneath petermann gletscher ice shelf, greenland. |
publisher |
American Geophysical Union |
publishDate |
2020 |
url |
http://nora.nerc.ac.uk/id/eprint/528633/ https://nora.nerc.ac.uk/id/eprint/528633/1/2020JC016427.pdf https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2020JC016427 |
long_lat |
ENVELOPE(-59.500,-59.500,80.500,80.500) |
geographic |
Greenland Petermann Gletscher |
geographic_facet |
Greenland Petermann Gletscher |
genre |
Greenland Ice Shelf Petermann gletscher |
genre_facet |
Greenland Ice Shelf Petermann gletscher |
op_relation |
https://nora.nerc.ac.uk/id/eprint/528633/1/2020JC016427.pdf Washam, Peter; Nicholls, Keith orcid:0000-0002-2188-4509 Muenchow, Andreas; Padman, Laurie. 2020 Tidal modulation of buoyant flow and basal melt beneath Petermann Gletscher Ice Shelf, Greenland. Journal of Geophysical Research: Oceans, 125 (10), e2020JC016427. 19, pp. https://doi.org/10.1029/2020JC016427 <https://doi.org/10.1029/2020JC016427> |
op_rights |
cc_by_4 |
op_doi |
https://doi.org/10.1029/2020JC016427 |
container_title |
Journal of Geophysical Research: Oceans |
container_volume |
125 |
container_issue |
10 |
_version_ |
1790600891898789888 |