Mechanisms and pathways of ocean heat anomalies in the Arctic-Atlantic region
Along the Atlantic water pathway, from the Gulf Stream in the south to the Arctic Ocean in the north, variability in ocean heat content is pronounced on interannual to decadal time scales. Ocean heat anomalies in this Arctic-Atlantic sector are known to affect Arctic sea ice extent, marine ecosystem...
Published in: | Geophysical Research Letters |
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Format: | Doctoral or Postdoctoral Thesis |
Language: | English |
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The University of Bergen
2020
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Online Access: | https://hdl.handle.net/11250/2712025 |
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ftunivbergen:oai:bora.uib.no:11250/2712025 2023-05-15T14:28:05+02:00 Mechanisms and pathways of ocean heat anomalies in the Arctic-Atlantic region Asbjørnsen, Helene 2020-11-20T09:54:53Z application/pdf https://hdl.handle.net/11250/2712025 eng eng The University of Bergen Paper I: Asbjørnsen, H., Johnson, H., Årthun, M., Linking variable Nordic Seas inflow to upstream circulation anomalies. The article is not available in BORA. Paper II: Asbjørnsen, H., Årthun, M., Skagseth, Ø. Eldevik, T., (2019) Mechanisms of ocean heat anomalies in the Norwegian Sea, Journal of Geophysical Research: Oceans, 124(4), 2908-2923. The article is available at: https://hdl.handle.net/1956/20665 Paper III: Asbjørnsen, H., Årthun, M., Skagseth, Ø. Eldevik, T., (2020) Mechanisms underlying recent Arctic Atlantification, Geophysical Research Letters, 47(15), 1-9. The article is available in the main thesis. The article is also available at: https://doi.org/10.1029/2020GL088036 container/ff/79/61/78/ff796178-1095-44a2-bcea-943e73cf728e urn:isbn:9788230866177 urn:isbn:9788230843482 https://hdl.handle.net/11250/2712025 In copyright http://rightsstatements.org/page/InC/1.0/ Copyright the Author. All rights reserved Doctoral thesis 2020 ftunivbergen https://doi.org/10.1029/2020GL088036 2023-03-14T17:44:11Z Along the Atlantic water pathway, from the Gulf Stream in the south to the Arctic Ocean in the north, variability in ocean heat content is pronounced on interannual to decadal time scales. Ocean heat anomalies in this Arctic-Atlantic sector are known to affect Arctic sea ice extent, marine ecosystems, and continental climate. However, there is at present neither consensus nor any complete understanding of the mechanisms causing such heat anomalies. This dissertation obtains a more robust understanding of regional ocean heat content variability by assessing the mechanisms and pathways of ocean heat anomalies in the Arctic-Atlantic region. The results are presented in three papers. The first paper investigates the link between a variable Nordic Seas inflow and large- scale ocean circulation changes upstream. Using a global, eddy-permitting ocean hind- cast together with a Lagrangian analysis tool, numerical particles are seeded at the Iceland-Scotland Ridge and tracked backward in time. Water from the subtropics sup- plied by the North Atlantic Current (NAC) is found to be the main component of the Nordic Seas inflow (64%), while 26% of the inflow has a subpolar or Arctic origin. Different atmospheric patterns are seen to affect the circulation strength along the ad- vective pathways, as well as the supply of subtropical and Arctic-origin water to the ridge through shifts in the NAC and the subpolar front. A robust link between a high transport of Arctic-origin water and a cold and fresh inflow is furthermore established, while a high transport of subtropical water leads to higher inflow salinities. The second paper investigates the mechanisms of interannual heat content variability in the Nor- wegian Sea downstream of the Iceland-Scotland Ridge, using a state-of-the-art ocean state estimate and closed heat budget diagnostics. Ocean advection is found to be the primary contributor to heat content variability in the Atlantic domain of the Norwegian Sea, although local surface fluxes also play an active role. ... Doctoral or Postdoctoral Thesis Arctic Arctic Arctic Ocean Iceland Nordic Seas north atlantic current North Atlantic Norwegian Sea Sea ice University of Bergen: Bergen Open Research Archive (BORA-UiB) Arctic Arctic Ocean Norwegian Sea Geophysical Research Letters 47 15 |
institution |
Open Polar |
collection |
University of Bergen: Bergen Open Research Archive (BORA-UiB) |
op_collection_id |
ftunivbergen |
language |
English |
description |
Along the Atlantic water pathway, from the Gulf Stream in the south to the Arctic Ocean in the north, variability in ocean heat content is pronounced on interannual to decadal time scales. Ocean heat anomalies in this Arctic-Atlantic sector are known to affect Arctic sea ice extent, marine ecosystems, and continental climate. However, there is at present neither consensus nor any complete understanding of the mechanisms causing such heat anomalies. This dissertation obtains a more robust understanding of regional ocean heat content variability by assessing the mechanisms and pathways of ocean heat anomalies in the Arctic-Atlantic region. The results are presented in three papers. The first paper investigates the link between a variable Nordic Seas inflow and large- scale ocean circulation changes upstream. Using a global, eddy-permitting ocean hind- cast together with a Lagrangian analysis tool, numerical particles are seeded at the Iceland-Scotland Ridge and tracked backward in time. Water from the subtropics sup- plied by the North Atlantic Current (NAC) is found to be the main component of the Nordic Seas inflow (64%), while 26% of the inflow has a subpolar or Arctic origin. Different atmospheric patterns are seen to affect the circulation strength along the ad- vective pathways, as well as the supply of subtropical and Arctic-origin water to the ridge through shifts in the NAC and the subpolar front. A robust link between a high transport of Arctic-origin water and a cold and fresh inflow is furthermore established, while a high transport of subtropical water leads to higher inflow salinities. The second paper investigates the mechanisms of interannual heat content variability in the Nor- wegian Sea downstream of the Iceland-Scotland Ridge, using a state-of-the-art ocean state estimate and closed heat budget diagnostics. Ocean advection is found to be the primary contributor to heat content variability in the Atlantic domain of the Norwegian Sea, although local surface fluxes also play an active role. ... |
format |
Doctoral or Postdoctoral Thesis |
author |
Asbjørnsen, Helene |
spellingShingle |
Asbjørnsen, Helene Mechanisms and pathways of ocean heat anomalies in the Arctic-Atlantic region |
author_facet |
Asbjørnsen, Helene |
author_sort |
Asbjørnsen, Helene |
title |
Mechanisms and pathways of ocean heat anomalies in the Arctic-Atlantic region |
title_short |
Mechanisms and pathways of ocean heat anomalies in the Arctic-Atlantic region |
title_full |
Mechanisms and pathways of ocean heat anomalies in the Arctic-Atlantic region |
title_fullStr |
Mechanisms and pathways of ocean heat anomalies in the Arctic-Atlantic region |
title_full_unstemmed |
Mechanisms and pathways of ocean heat anomalies in the Arctic-Atlantic region |
title_sort |
mechanisms and pathways of ocean heat anomalies in the arctic-atlantic region |
publisher |
The University of Bergen |
publishDate |
2020 |
url |
https://hdl.handle.net/11250/2712025 |
geographic |
Arctic Arctic Ocean Norwegian Sea |
geographic_facet |
Arctic Arctic Ocean Norwegian Sea |
genre |
Arctic Arctic Arctic Ocean Iceland Nordic Seas north atlantic current North Atlantic Norwegian Sea Sea ice |
genre_facet |
Arctic Arctic Arctic Ocean Iceland Nordic Seas north atlantic current North Atlantic Norwegian Sea Sea ice |
op_relation |
Paper I: Asbjørnsen, H., Johnson, H., Årthun, M., Linking variable Nordic Seas inflow to upstream circulation anomalies. The article is not available in BORA. Paper II: Asbjørnsen, H., Årthun, M., Skagseth, Ø. Eldevik, T., (2019) Mechanisms of ocean heat anomalies in the Norwegian Sea, Journal of Geophysical Research: Oceans, 124(4), 2908-2923. The article is available at: https://hdl.handle.net/1956/20665 Paper III: Asbjørnsen, H., Årthun, M., Skagseth, Ø. Eldevik, T., (2020) Mechanisms underlying recent Arctic Atlantification, Geophysical Research Letters, 47(15), 1-9. The article is available in the main thesis. The article is also available at: https://doi.org/10.1029/2020GL088036 container/ff/79/61/78/ff796178-1095-44a2-bcea-943e73cf728e urn:isbn:9788230866177 urn:isbn:9788230843482 https://hdl.handle.net/11250/2712025 |
op_rights |
In copyright http://rightsstatements.org/page/InC/1.0/ Copyright the Author. All rights reserved |
op_doi |
https://doi.org/10.1029/2020GL088036 |
container_title |
Geophysical Research Letters |
container_volume |
47 |
container_issue |
15 |
_version_ |
1766302227316604928 |