Export of Ice Sheet Meltwater from Upernavik Fjord, West Greenland
Meltwater from Greenland is an important freshwater source for the North Atlantic Ocean, released into the ocean at the head of fjords in the form of runoff, submarine melt, and icebergs. The meltwater release gives rise to complex in-fjord transformations that result in its dilution through mixing...
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ftosti:oai:osti.gov:1854351 2023-07-30T04:03:48+02:00 Export of Ice Sheet Meltwater from Upernavik Fjord, West Greenland Muilwijk, Morven Straneo, Fiamma Slater, Donald A. Smedsrud, Lars H. Holte, James Wood, Michael Andresen, Camilla S. Harden, Ben 2022-03-16 application/pdf http://www.osti.gov/servlets/purl/1854351 https://www.osti.gov/biblio/1854351 https://doi.org/10.1175/jpo-d-21-0084.1 unknown http://www.osti.gov/servlets/purl/1854351 https://www.osti.gov/biblio/1854351 https://doi.org/10.1175/jpo-d-21-0084.1 doi:10.1175/jpo-d-21-0084.1 58 GEOSCIENCES 2022 ftosti https://doi.org/10.1175/jpo-d-21-0084.1 2023-07-11T10:11:03Z Meltwater from Greenland is an important freshwater source for the North Atlantic Ocean, released into the ocean at the head of fjords in the form of runoff, submarine melt, and icebergs. The meltwater release gives rise to complex in-fjord transformations that result in its dilution through mixing with other water masses. The transformed waters, which contain the meltwater, are exported from the fjords as a new water mass Glacially Modified Water (GMW). Here we use summer hydrographic data collected from 2013 to 2019 in Upernavik, a major glacial fjord in northwest Greenland, to describe the water masses that flow into the fjord from the shelf and the exported GMWs. Using an optimum multi-parameter technique across multiple years we then show that GMW is composed of 57.8% ± 8.1% Atlantic Water (AW), 41.0% ± 8.3% Polar Water (PW), 1.0% ± 0.1% subglacial discharge, and 0.2% ± 0.2% submarine meltwater. We show that the GMW fractional composition cannot be described by buoyant plume theory alone since it includes lateral mixing within the upper layers of the fjord not accounted for by buoyant plume dynamics. Consistent with its composition, we find that changes in GMW properties reflect changes in the AW and PW source waters. Using the obtained dilution ratios, this study suggests that the exchange across the fjord mouth during summer is on the order of 50 mSv (1 Sv ≡ 10 6 m 3 s –1 ) (compared to a freshwater input of 0.5 mSv). This study provides a first-order parameterization for the exchange at the mouth of glacial fjords for large-scale ocean models. Other/Unknown Material Greenland Ice Sheet North Atlantic Upernavik SciTec Connect (Office of Scientific and Technical Information - OSTI, U.S. Department of Energy) Greenland Journal of Physical Oceanography 52 3 363 382 |
institution |
Open Polar |
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SciTec Connect (Office of Scientific and Technical Information - OSTI, U.S. Department of Energy) |
op_collection_id |
ftosti |
language |
unknown |
topic |
58 GEOSCIENCES |
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58 GEOSCIENCES Muilwijk, Morven Straneo, Fiamma Slater, Donald A. Smedsrud, Lars H. Holte, James Wood, Michael Andresen, Camilla S. Harden, Ben Export of Ice Sheet Meltwater from Upernavik Fjord, West Greenland |
topic_facet |
58 GEOSCIENCES |
description |
Meltwater from Greenland is an important freshwater source for the North Atlantic Ocean, released into the ocean at the head of fjords in the form of runoff, submarine melt, and icebergs. The meltwater release gives rise to complex in-fjord transformations that result in its dilution through mixing with other water masses. The transformed waters, which contain the meltwater, are exported from the fjords as a new water mass Glacially Modified Water (GMW). Here we use summer hydrographic data collected from 2013 to 2019 in Upernavik, a major glacial fjord in northwest Greenland, to describe the water masses that flow into the fjord from the shelf and the exported GMWs. Using an optimum multi-parameter technique across multiple years we then show that GMW is composed of 57.8% ± 8.1% Atlantic Water (AW), 41.0% ± 8.3% Polar Water (PW), 1.0% ± 0.1% subglacial discharge, and 0.2% ± 0.2% submarine meltwater. We show that the GMW fractional composition cannot be described by buoyant plume theory alone since it includes lateral mixing within the upper layers of the fjord not accounted for by buoyant plume dynamics. Consistent with its composition, we find that changes in GMW properties reflect changes in the AW and PW source waters. Using the obtained dilution ratios, this study suggests that the exchange across the fjord mouth during summer is on the order of 50 mSv (1 Sv ≡ 10 6 m 3 s –1 ) (compared to a freshwater input of 0.5 mSv). This study provides a first-order parameterization for the exchange at the mouth of glacial fjords for large-scale ocean models. |
author |
Muilwijk, Morven Straneo, Fiamma Slater, Donald A. Smedsrud, Lars H. Holte, James Wood, Michael Andresen, Camilla S. Harden, Ben |
author_facet |
Muilwijk, Morven Straneo, Fiamma Slater, Donald A. Smedsrud, Lars H. Holte, James Wood, Michael Andresen, Camilla S. Harden, Ben |
author_sort |
Muilwijk, Morven |
title |
Export of Ice Sheet Meltwater from Upernavik Fjord, West Greenland |
title_short |
Export of Ice Sheet Meltwater from Upernavik Fjord, West Greenland |
title_full |
Export of Ice Sheet Meltwater from Upernavik Fjord, West Greenland |
title_fullStr |
Export of Ice Sheet Meltwater from Upernavik Fjord, West Greenland |
title_full_unstemmed |
Export of Ice Sheet Meltwater from Upernavik Fjord, West Greenland |
title_sort |
export of ice sheet meltwater from upernavik fjord, west greenland |
publishDate |
2022 |
url |
http://www.osti.gov/servlets/purl/1854351 https://www.osti.gov/biblio/1854351 https://doi.org/10.1175/jpo-d-21-0084.1 |
geographic |
Greenland |
geographic_facet |
Greenland |
genre |
Greenland Ice Sheet North Atlantic Upernavik |
genre_facet |
Greenland Ice Sheet North Atlantic Upernavik |
op_relation |
http://www.osti.gov/servlets/purl/1854351 https://www.osti.gov/biblio/1854351 https://doi.org/10.1175/jpo-d-21-0084.1 doi:10.1175/jpo-d-21-0084.1 |
op_doi |
https://doi.org/10.1175/jpo-d-21-0084.1 |
container_title |
Journal of Physical Oceanography |
container_volume |
52 |
container_issue |
3 |
container_start_page |
363 |
op_container_end_page |
382 |
_version_ |
1772814911461654528 |