Coupled atmosphere–ocean observations of a cold-air outbreak and its impact on the Iceland Sea
Marine cold-air outbreaks (CAO) 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 t...
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ftgfzpotsdam:oai:gfzpublic.gfz-potsdam.de:item_5016501 2023-10-09T21:52:39+02:00 Coupled atmosphere–ocean observations of a cold-air outbreak and its impact on the Iceland Sea Renfrew, I. Huang, J. Semper, S. Barrell, C. Terpstra, A. Pickart, R. Vage, K. Elvidge, A. Spengler, T. Strehl, A. Weiss, A. 2023 https://gfzpublic.gfz-potsdam.de/pubman/item/item_5016501 eng eng info:eu-repo/semantics/altIdentifier/doi/10.57757/IUGG23-0965 https://gfzpublic.gfz-potsdam.de/pubman/item/item_5016501 XXVIII General Assembly of the International Union of Geodesy and Geophysics (IUGG) info:eu-repo/semantics/conferenceObject 2023 ftgfzpotsdam https://doi.org/10.57757/IUGG23-0965 2023-09-10T23:43:22Z Marine cold-air outbreaks (CAO) 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 iswell 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 200m 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 itwarms. 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. Timeseries 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. Conference Object Iceland North Atlantic Sea ice GFZpublic (German Research Centre for Geosciences, Helmholtz-Zentrum Potsdam) |
institution |
Open Polar |
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GFZpublic (German Research Centre for Geosciences, Helmholtz-Zentrum Potsdam) |
op_collection_id |
ftgfzpotsdam |
language |
English |
description |
Marine cold-air outbreaks (CAO) 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 iswell 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 200m 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 itwarms. 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. Timeseries 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. |
format |
Conference Object |
author |
Renfrew, I. Huang, J. Semper, S. Barrell, C. Terpstra, A. Pickart, R. Vage, K. Elvidge, A. Spengler, T. Strehl, A. Weiss, A. |
spellingShingle |
Renfrew, I. Huang, J. Semper, S. Barrell, C. Terpstra, A. Pickart, R. Vage, K. Elvidge, A. Spengler, T. Strehl, A. Weiss, A. Coupled atmosphere–ocean observations of a cold-air outbreak and its impact on the Iceland Sea |
author_facet |
Renfrew, I. Huang, J. Semper, S. Barrell, C. Terpstra, A. Pickart, R. Vage, K. Elvidge, A. Spengler, T. Strehl, A. Weiss, A. |
author_sort |
Renfrew, I. |
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 |
publishDate |
2023 |
url |
https://gfzpublic.gfz-potsdam.de/pubman/item/item_5016501 |
genre |
Iceland North Atlantic Sea ice |
genre_facet |
Iceland North Atlantic Sea ice |
op_source |
XXVIII General Assembly of the International Union of Geodesy and Geophysics (IUGG) |
op_relation |
info:eu-repo/semantics/altIdentifier/doi/10.57757/IUGG23-0965 https://gfzpublic.gfz-potsdam.de/pubman/item/item_5016501 |
op_doi |
https://doi.org/10.57757/IUGG23-0965 |
_version_ |
1779315815140556800 |