Coupled atmosphere–ocean observations of a cold‐air outbreak and its impact on the Iceland Sea
Abstract Marine cold‐air outbreaks (CAOs) are vigorous equatorward excursions of cold air over the ocean, responsible for the majority of wintertime oceanic heat loss from the subpolar seas of the North Atlantic. However, the impact of individual CAO events on the ocean is poorly understood. Here we...
Published in: | Quarterly Journal of the Royal Meteorological Society |
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crwiley:10.1002/qj.4418 2024-06-02T08:09:00+00:00 Coupled atmosphere–ocean observations of a cold‐air outbreak and its impact on the Iceland Sea Renfrew, Ian A. Huang, Jie Semper, Stefanie Barrell, Christopher Terpstra, Annick Pickart, Robert S. Våge, Kjetil Elvidge, Andrew D. Spengler, Thomas Strehl, Anna‐Marie Weiss, Alexandra National Science Foundation of Sri Lanka Natural Environment Research Council Norges Forskningsråd Sixth Framework Programme Trond Mohn stiftelse Research Council of Norway 2023 http://dx.doi.org/10.1002/qj.4418 https://onlinelibrary.wiley.com/doi/pdf/10.1002/qj.4418 https://onlinelibrary.wiley.com/doi/full-xml/10.1002/qj.4418 https://rmets.onlinelibrary.wiley.com/doi/pdf/10.1002/qj.4418 en eng Wiley http://creativecommons.org/licenses/by/4.0/ Quarterly Journal of the Royal Meteorological Society volume 149, issue 751, page 472-493 ISSN 0035-9009 1477-870X journal-article 2023 crwiley https://doi.org/10.1002/qj.4418 2024-05-03T11:19:38Z Abstract Marine cold‐air outbreaks (CAOs) are vigorous equatorward excursions of cold air over the ocean, responsible for the majority of wintertime oceanic heat loss from the subpolar seas of the North Atlantic. However, the impact of individual CAO events on the ocean is poorly understood. Here we present the first coupled observations of the atmosphere and ocean during a wintertime CAO event, between 28 February and 13 March 2018, in the subpolar North Atlantic region. Comprehensive observations are presented from five aircraft flights, a research vessel, a meteorological buoy, a subsurface mooring, an ocean glider, and an Argo float. The CAO event starts abruptly with substantial changes in temperature, humidity and wind throughout the atmospheric boundary layer. The CAO is well mixed vertically and, away from the sea‐ice edge, relatively homogeneous spatially. During the CAO peak, higher sensible heat fluxes occupy at least the lowest 200 m of the atmospheric boundary layer, while higher latent heat fluxes are confined to the surface layer. The response of the ocean to the CAO is spatially dependent. In the interior of the Iceland Sea the mixed layer cools, while in the boundary current region it warms. In both locations, the mixed layer deepens and becomes more saline. Combining our observations with one‐dimensional mixed‐layer modelling, we show that in the interior of the Iceland Sea, atmospheric forcing dominates the ocean response. In contrast, in the boundary current region lateral advection and mixing counteract the short‐term impact of the atmospheric forcing. Time series observations of the late‐winter period illustrate a highly variable ocean mixed layer, with lateral advection and mixing often masking the ocean's general cooling and deepening response to individual CAO events. Article in Journal/Newspaper Iceland North Atlantic Sea ice Wiley Online Library Quarterly Journal of the Royal Meteorological Society 149 751 472 493 |
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Open Polar |
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Wiley Online Library |
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crwiley |
language |
English |
description |
Abstract Marine cold‐air outbreaks (CAOs) are vigorous equatorward excursions of cold air over the ocean, responsible for the majority of wintertime oceanic heat loss from the subpolar seas of the North Atlantic. However, the impact of individual CAO events on the ocean is poorly understood. Here we present the first coupled observations of the atmosphere and ocean during a wintertime CAO event, between 28 February and 13 March 2018, in the subpolar North Atlantic region. Comprehensive observations are presented from five aircraft flights, a research vessel, a meteorological buoy, a subsurface mooring, an ocean glider, and an Argo float. The CAO event starts abruptly with substantial changes in temperature, humidity and wind throughout the atmospheric boundary layer. The CAO is well mixed vertically and, away from the sea‐ice edge, relatively homogeneous spatially. During the CAO peak, higher sensible heat fluxes occupy at least the lowest 200 m of the atmospheric boundary layer, while higher latent heat fluxes are confined to the surface layer. The response of the ocean to the CAO is spatially dependent. In the interior of the Iceland Sea the mixed layer cools, while in the boundary current region it warms. In both locations, the mixed layer deepens and becomes more saline. Combining our observations with one‐dimensional mixed‐layer modelling, we show that in the interior of the Iceland Sea, atmospheric forcing dominates the ocean response. In contrast, in the boundary current region lateral advection and mixing counteract the short‐term impact of the atmospheric forcing. Time series observations of the late‐winter period illustrate a highly variable ocean mixed layer, with lateral advection and mixing often masking the ocean's general cooling and deepening response to individual CAO events. |
author2 |
National Science Foundation of Sri Lanka Natural Environment Research Council Norges Forskningsråd Sixth Framework Programme Trond Mohn stiftelse Research Council of Norway |
format |
Article in Journal/Newspaper |
author |
Renfrew, Ian A. Huang, Jie Semper, Stefanie Barrell, Christopher Terpstra, Annick Pickart, Robert S. Våge, Kjetil Elvidge, Andrew D. Spengler, Thomas Strehl, Anna‐Marie Weiss, Alexandra |
spellingShingle |
Renfrew, Ian A. Huang, Jie Semper, Stefanie Barrell, Christopher Terpstra, Annick Pickart, Robert S. Våge, Kjetil Elvidge, Andrew D. Spengler, Thomas Strehl, Anna‐Marie Weiss, Alexandra Coupled atmosphere–ocean observations of a cold‐air outbreak and its impact on the Iceland Sea |
author_facet |
Renfrew, Ian A. Huang, Jie Semper, Stefanie Barrell, Christopher Terpstra, Annick Pickart, Robert S. Våge, Kjetil Elvidge, Andrew D. Spengler, Thomas Strehl, Anna‐Marie Weiss, Alexandra |
author_sort |
Renfrew, Ian A. |
title |
Coupled atmosphere–ocean observations of a cold‐air outbreak and its impact on the Iceland Sea |
title_short |
Coupled atmosphere–ocean observations of a cold‐air outbreak and its impact on the Iceland Sea |
title_full |
Coupled atmosphere–ocean observations of a cold‐air outbreak and its impact on the Iceland Sea |
title_fullStr |
Coupled atmosphere–ocean observations of a cold‐air outbreak and its impact on the Iceland Sea |
title_full_unstemmed |
Coupled atmosphere–ocean observations of a cold‐air outbreak and its impact on the Iceland Sea |
title_sort |
coupled atmosphere–ocean observations of a cold‐air outbreak and its impact on the iceland sea |
publisher |
Wiley |
publishDate |
2023 |
url |
http://dx.doi.org/10.1002/qj.4418 https://onlinelibrary.wiley.com/doi/pdf/10.1002/qj.4418 https://onlinelibrary.wiley.com/doi/full-xml/10.1002/qj.4418 https://rmets.onlinelibrary.wiley.com/doi/pdf/10.1002/qj.4418 |
genre |
Iceland North Atlantic Sea ice |
genre_facet |
Iceland North Atlantic Sea ice |
op_source |
Quarterly Journal of the Royal Meteorological Society volume 149, issue 751, page 472-493 ISSN 0035-9009 1477-870X |
op_rights |
http://creativecommons.org/licenses/by/4.0/ |
op_doi |
https://doi.org/10.1002/qj.4418 |
container_title |
Quarterly Journal of the Royal Meteorological Society |
container_volume |
149 |
container_issue |
751 |
container_start_page |
472 |
op_container_end_page |
493 |
_version_ |
1800754589918560256 |