Wintertime atmospheric response to Atlantic multidecadal variability: effect of stratospheric representation and ocean–atmosphere coupling
The impact of the Atlantic multidecadal variability (AMV) on the wintertime atmosphere circulation is investigated using three different configurations of the Community Atmospheric Model version 5 (CAM5). Realistic SST and sea ice anomalies associated with the AMV in observations are prescribed in C...
Published in: | Climate Dynamics |
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2016
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Online Access: | https://escholarship.org/uc/item/445409r9 https://escholarship.org/content/qt445409r9/qt445409r9.pdf https://doi.org/10.1007/s00382-015-2887-4 |
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ftcdlib:oai:escholarship.org:ark:/13030/qt445409r9 2024-09-09T19:56:00+00:00 Wintertime atmospheric response to Atlantic multidecadal variability: effect of stratospheric representation and ocean–atmosphere coupling Peings, Yannick Magnusdottir, Gudrun 1029 - 1047 2016-08-01 application/pdf https://escholarship.org/uc/item/445409r9 https://escholarship.org/content/qt445409r9/qt445409r9.pdf https://doi.org/10.1007/s00382-015-2887-4 unknown eScholarship, University of California qt445409r9 https://escholarship.org/uc/item/445409r9 https://escholarship.org/content/qt445409r9/qt445409r9.pdf doi:10.1007/s00382-015-2887-4 CC-BY Climate Dynamics, vol 47, iss 3-4 Climate Action Atlantic multidecadal variability North Atlantic Oscillation Teleconnection Cold extremes Decadal forecasting Jet stream Rossby waves Stratosphere-troposphere coupling Ocean-atmosphere feedback Atmospheric Sciences Oceanography Physical Geography and Environmental Geoscience Meteorology & Atmospheric Sciences article 2016 ftcdlib https://doi.org/10.1007/s00382-015-2887-4 2024-06-28T06:28:19Z The impact of the Atlantic multidecadal variability (AMV) on the wintertime atmosphere circulation is investigated using three different configurations of the Community Atmospheric Model version 5 (CAM5). Realistic SST and sea ice anomalies associated with the AMV in observations are prescribed in CAM5 (low-top model) and WACCM5 (high-top model) to assess the dependence of the results on the representation of the stratosphere. In a third experiment, the role of ocean–atmosphere feedback is investigated by coupling CAM5 to a slab-ocean model in which the AMV forcing is prescribed through oceanic heat flux anomalies. The three experiments give consistent results concerning the response of the NAO in winter, with a negative NAO signal in response to a warming of the North Atlantic ocean. This response is found in early winter when the high-top model is used, and in late winter with the low-top model. With the slab-ocean, the negative NAO response is more persistent in winter and shifted eastward over the continent due to the damping of the atmospheric response over the North Atlantic ocean. Additional experiments suggest that both tropical and extratropical SST anomalies are needed to obtain a significant modulation of the NAO, with small influence of sea ice anomalies. Warm tropical SST anomalies induce a northward shift of the ITCZ and a Rossby-wave response that is reinforced in the mid-latitudes by the extratropical SST anomalies through eddy–mean flow interactions. This modeling study supports that the positive phase of the AMV promotes the negative NAO in winter, while illustrating the impacts of the stratosphere and of the ocean–atmosphere feedbacks in the spatial pattern and timing of this response. Article in Journal/Newspaper North Atlantic North Atlantic oscillation Sea ice University of California: eScholarship Climate Dynamics 47 3-4 1029 1047 |
institution |
Open Polar |
collection |
University of California: eScholarship |
op_collection_id |
ftcdlib |
language |
unknown |
topic |
Climate Action Atlantic multidecadal variability North Atlantic Oscillation Teleconnection Cold extremes Decadal forecasting Jet stream Rossby waves Stratosphere-troposphere coupling Ocean-atmosphere feedback Atmospheric Sciences Oceanography Physical Geography and Environmental Geoscience Meteorology & Atmospheric Sciences |
spellingShingle |
Climate Action Atlantic multidecadal variability North Atlantic Oscillation Teleconnection Cold extremes Decadal forecasting Jet stream Rossby waves Stratosphere-troposphere coupling Ocean-atmosphere feedback Atmospheric Sciences Oceanography Physical Geography and Environmental Geoscience Meteorology & Atmospheric Sciences Peings, Yannick Magnusdottir, Gudrun Wintertime atmospheric response to Atlantic multidecadal variability: effect of stratospheric representation and ocean–atmosphere coupling |
topic_facet |
Climate Action Atlantic multidecadal variability North Atlantic Oscillation Teleconnection Cold extremes Decadal forecasting Jet stream Rossby waves Stratosphere-troposphere coupling Ocean-atmosphere feedback Atmospheric Sciences Oceanography Physical Geography and Environmental Geoscience Meteorology & Atmospheric Sciences |
description |
The impact of the Atlantic multidecadal variability (AMV) on the wintertime atmosphere circulation is investigated using three different configurations of the Community Atmospheric Model version 5 (CAM5). Realistic SST and sea ice anomalies associated with the AMV in observations are prescribed in CAM5 (low-top model) and WACCM5 (high-top model) to assess the dependence of the results on the representation of the stratosphere. In a third experiment, the role of ocean–atmosphere feedback is investigated by coupling CAM5 to a slab-ocean model in which the AMV forcing is prescribed through oceanic heat flux anomalies. The three experiments give consistent results concerning the response of the NAO in winter, with a negative NAO signal in response to a warming of the North Atlantic ocean. This response is found in early winter when the high-top model is used, and in late winter with the low-top model. With the slab-ocean, the negative NAO response is more persistent in winter and shifted eastward over the continent due to the damping of the atmospheric response over the North Atlantic ocean. Additional experiments suggest that both tropical and extratropical SST anomalies are needed to obtain a significant modulation of the NAO, with small influence of sea ice anomalies. Warm tropical SST anomalies induce a northward shift of the ITCZ and a Rossby-wave response that is reinforced in the mid-latitudes by the extratropical SST anomalies through eddy–mean flow interactions. This modeling study supports that the positive phase of the AMV promotes the negative NAO in winter, while illustrating the impacts of the stratosphere and of the ocean–atmosphere feedbacks in the spatial pattern and timing of this response. |
format |
Article in Journal/Newspaper |
author |
Peings, Yannick Magnusdottir, Gudrun |
author_facet |
Peings, Yannick Magnusdottir, Gudrun |
author_sort |
Peings, Yannick |
title |
Wintertime atmospheric response to Atlantic multidecadal variability: effect of stratospheric representation and ocean–atmosphere coupling |
title_short |
Wintertime atmospheric response to Atlantic multidecadal variability: effect of stratospheric representation and ocean–atmosphere coupling |
title_full |
Wintertime atmospheric response to Atlantic multidecadal variability: effect of stratospheric representation and ocean–atmosphere coupling |
title_fullStr |
Wintertime atmospheric response to Atlantic multidecadal variability: effect of stratospheric representation and ocean–atmosphere coupling |
title_full_unstemmed |
Wintertime atmospheric response to Atlantic multidecadal variability: effect of stratospheric representation and ocean–atmosphere coupling |
title_sort |
wintertime atmospheric response to atlantic multidecadal variability: effect of stratospheric representation and ocean–atmosphere coupling |
publisher |
eScholarship, University of California |
publishDate |
2016 |
url |
https://escholarship.org/uc/item/445409r9 https://escholarship.org/content/qt445409r9/qt445409r9.pdf https://doi.org/10.1007/s00382-015-2887-4 |
op_coverage |
1029 - 1047 |
genre |
North Atlantic North Atlantic oscillation Sea ice |
genre_facet |
North Atlantic North Atlantic oscillation Sea ice |
op_source |
Climate Dynamics, vol 47, iss 3-4 |
op_relation |
qt445409r9 https://escholarship.org/uc/item/445409r9 https://escholarship.org/content/qt445409r9/qt445409r9.pdf doi:10.1007/s00382-015-2887-4 |
op_rights |
CC-BY |
op_doi |
https://doi.org/10.1007/s00382-015-2887-4 |
container_title |
Climate Dynamics |
container_volume |
47 |
container_issue |
3-4 |
container_start_page |
1029 |
op_container_end_page |
1047 |
_version_ |
1809926446089502720 |