Key Role of the Ocean Western Boundary currents in shaping the Northern Hemisphere climate
The individual impact of North Atlantic and Pacific Ocean Western Boundary Currents (OWBCs) on the tropospheric circulation has recently been studied in depth. However, their simultaneous role in shaping the hemisphere-scale wintertime troposphere/stratosphere-coupled circulation and its variability...
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Online Access: | https://hdl.handle.net/1956/23716 https://doi.org/10.1038/s41598-019-39392-y |
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ftunivbergen:oai:bora.uib.no:1956/23716 2023-05-15T17:30:36+02:00 Key Role of the Ocean Western Boundary currents in shaping the Northern Hemisphere climate Omrani, Nour-Eddine Ogawa, Fumiaki Nakamura, Hisashi Keenlyside, Noel Lubis, Sandro W. Matthes, Katja 2019-12-19T14:46:36Z application/pdf https://hdl.handle.net/1956/23716 https://doi.org/10.1038/s41598-019-39392-y eng eng Nature Research Notur/NorStore: NS9064K urn:issn:2045-2322 https://hdl.handle.net/1956/23716 https://doi.org/10.1038/s41598-019-39392-y cristin:1654816 Attribution CC BY http://creativecommons.org/licenses/by/4.0 Copyright 2019 The Author(s) Scientific Reports Peer reviewed Journal article 2019 ftunivbergen https://doi.org/10.1038/s41598-019-39392-y 2023-03-14T17:44:35Z The individual impact of North Atlantic and Pacific Ocean Western Boundary Currents (OWBCs) on the tropospheric circulation has recently been studied in depth. However, their simultaneous role in shaping the hemisphere-scale wintertime troposphere/stratosphere-coupled circulation and its variability have not been considered. Through semi-idealized Atmospheric General-Circulation-Model experiments, we show that the North Atlantic and Pacific OWBCs jointly maintain and shape the wintertime hemispheric circulation and its leading mode of variability Northern Annular Mode (NAM). The OWBCs energize baroclinic waves that reinforce quasi-annular hemispheric structure in the tropospheric eddy-driven jetstreams and NAM variability. Without the OWBCs, the wintertime NAM variability is much weaker and its impact on the continental and maritime surface climate is largely insignificant. Atmospheric energy redistribution caused by the OWBCs acts to damp the near-surface atmospheric baroclinicity and compensates the associated oceanic meridional energy transport. Furthermore, the OWBCs substantially weaken the wintertime stratospheric polar vortex by enhancing the upward planetary wave propagation, and thereby affecting both stratospheric and tropospheric NAM-annularity. Whereas the overall impact of the extra-tropical OWBCs on the stratosphere results mainly from the Pacific, the impact on the troposphere results from both the Pacific and Atlantic OWBCs. publishedVersion Article in Journal/Newspaper North Atlantic University of Bergen: Bergen Open Research Archive (BORA-UiB) Pacific Scientific Reports 9 1 |
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Open Polar |
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University of Bergen: Bergen Open Research Archive (BORA-UiB) |
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ftunivbergen |
language |
English |
description |
The individual impact of North Atlantic and Pacific Ocean Western Boundary Currents (OWBCs) on the tropospheric circulation has recently been studied in depth. However, their simultaneous role in shaping the hemisphere-scale wintertime troposphere/stratosphere-coupled circulation and its variability have not been considered. Through semi-idealized Atmospheric General-Circulation-Model experiments, we show that the North Atlantic and Pacific OWBCs jointly maintain and shape the wintertime hemispheric circulation and its leading mode of variability Northern Annular Mode (NAM). The OWBCs energize baroclinic waves that reinforce quasi-annular hemispheric structure in the tropospheric eddy-driven jetstreams and NAM variability. Without the OWBCs, the wintertime NAM variability is much weaker and its impact on the continental and maritime surface climate is largely insignificant. Atmospheric energy redistribution caused by the OWBCs acts to damp the near-surface atmospheric baroclinicity and compensates the associated oceanic meridional energy transport. Furthermore, the OWBCs substantially weaken the wintertime stratospheric polar vortex by enhancing the upward planetary wave propagation, and thereby affecting both stratospheric and tropospheric NAM-annularity. Whereas the overall impact of the extra-tropical OWBCs on the stratosphere results mainly from the Pacific, the impact on the troposphere results from both the Pacific and Atlantic OWBCs. publishedVersion |
format |
Article in Journal/Newspaper |
author |
Omrani, Nour-Eddine Ogawa, Fumiaki Nakamura, Hisashi Keenlyside, Noel Lubis, Sandro W. Matthes, Katja |
spellingShingle |
Omrani, Nour-Eddine Ogawa, Fumiaki Nakamura, Hisashi Keenlyside, Noel Lubis, Sandro W. Matthes, Katja Key Role of the Ocean Western Boundary currents in shaping the Northern Hemisphere climate |
author_facet |
Omrani, Nour-Eddine Ogawa, Fumiaki Nakamura, Hisashi Keenlyside, Noel Lubis, Sandro W. Matthes, Katja |
author_sort |
Omrani, Nour-Eddine |
title |
Key Role of the Ocean Western Boundary currents in shaping the Northern Hemisphere climate |
title_short |
Key Role of the Ocean Western Boundary currents in shaping the Northern Hemisphere climate |
title_full |
Key Role of the Ocean Western Boundary currents in shaping the Northern Hemisphere climate |
title_fullStr |
Key Role of the Ocean Western Boundary currents in shaping the Northern Hemisphere climate |
title_full_unstemmed |
Key Role of the Ocean Western Boundary currents in shaping the Northern Hemisphere climate |
title_sort |
key role of the ocean western boundary currents in shaping the northern hemisphere climate |
publisher |
Nature Research |
publishDate |
2019 |
url |
https://hdl.handle.net/1956/23716 https://doi.org/10.1038/s41598-019-39392-y |
geographic |
Pacific |
geographic_facet |
Pacific |
genre |
North Atlantic |
genre_facet |
North Atlantic |
op_source |
Scientific Reports |
op_relation |
Notur/NorStore: NS9064K urn:issn:2045-2322 https://hdl.handle.net/1956/23716 https://doi.org/10.1038/s41598-019-39392-y cristin:1654816 |
op_rights |
Attribution CC BY http://creativecommons.org/licenses/by/4.0 Copyright 2019 The Author(s) |
op_doi |
https://doi.org/10.1038/s41598-019-39392-y |
container_title |
Scientific Reports |
container_volume |
9 |
container_issue |
1 |
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1766127455378079744 |