North Atlantic Ocean Internal Decadal Variability: Role of the Mean State and Ocean-Atmosphere Coupling
The origin of the decadal variability in the North Atlantic Ocean is investigated in a series of coupled and ocean-only numerical experiments. Two versions of the IPSL-CM5A model are considered, differing only by their atmospheric horizontal resolution (3.75 degrees x1.87 degrees and 2.5 degrees x1....
Published in: | Journal of Geophysical Research: Oceans |
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Language: | English |
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Amer Geophysical Union
2018
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Online Access: | https://archimer.ifremer.fr/doc/00462/57374/59434.pdf https://archimer.ifremer.fr/doc/00462/57374/59435.pdf https://doi.org/10.1029/2018JC014074 https://archimer.ifremer.fr/doc/00462/57374/ |
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ftarchimer:oai:archimer.ifremer.fr:57374 2023-05-15T17:28:35+02:00 North Atlantic Ocean Internal Decadal Variability: Role of the Mean State and Ocean-Atmosphere Coupling Gastineau, Guillaume Mignot, Juliette Arzel, Olivier Huck, Thierry 2018-08 application/pdf https://archimer.ifremer.fr/doc/00462/57374/59434.pdf https://archimer.ifremer.fr/doc/00462/57374/59435.pdf https://doi.org/10.1029/2018JC014074 https://archimer.ifremer.fr/doc/00462/57374/ eng eng Amer Geophysical Union info:eu-repo/grantAgreement/EC/FP7/312979/EU//IS-ENES2 https://archimer.ifremer.fr/doc/00462/57374/59434.pdf https://archimer.ifremer.fr/doc/00462/57374/59435.pdf doi:10.1029/2018JC014074 https://archimer.ifremer.fr/doc/00462/57374/ info:eu-repo/semantics/openAccess restricted use Journal Of Geophysical Research-oceans (2169-9275) (Amer Geophysical Union), 2018-08 , Vol. 123 , N. 8 , P. 5949-5970 climate variability Atlantic Ocean atmosphere-ocean general circulation models air-sea interactions Atlantic subpolar gyre Atlantic Meridional Overturning Circulation text Publication info:eu-repo/semantics/article 2018 ftarchimer https://doi.org/10.1029/2018JC014074 2021-09-23T20:31:38Z The origin of the decadal variability in the North Atlantic Ocean is investigated in a series of coupled and ocean-only numerical experiments. Two versions of the IPSL-CM5A model are considered, differing only by their atmospheric horizontal resolution (3.75 degrees x1.87 degrees and 2.5 degrees x1.25 degrees). When the ocean model is forced by the climatological surface fluxes from the low atmospheric resolution coupled model version, a 20-year variability emerges, similar to the variability found in the coupled simulation. Such decadal variability is consistent with a large-scale baroclinic instability of the mean flow in the west European basin. Increasing the atmospheric resolution leads to a more intense Icelandic low, which intensifies the western subpolar gyre, and warms the eastern North Atlantic subpolar gyre region. The mean state changes nearly vanish the associated internal oceanic variability under the corresponding climatological surface fluxes. Increasing the atmospheric resolution also produces a slightly weaker atmospheric stochastic forcing. Both the mean state and atmospheric variability changes are consistent with the decreasing amplitude of the variability in the coupled model. For both model versions, the amplitude of the internal oceanic variability is strongly enhanced in the presence of atmospheric stochastic forcing. Air-sea coupling on the other hand has a moderate influence on the amplitude of the variability only in the low-resolution model version, where the North Atlantic oceanic variability at 20years increases by 23% due to coupling. The coupling effect is therefore modest and sensitive to the atmospheric horizontal resolution. Article in Journal/Newspaper North Atlantic Archimer (Archive Institutionnelle de l'Ifremer - Institut français de recherche pour l'exploitation de la mer) West European Basin ENVELOPE(-28.000,-28.000,52.750,52.750) Journal of Geophysical Research: Oceans 123 8 5949 5970 |
institution |
Open Polar |
collection |
Archimer (Archive Institutionnelle de l'Ifremer - Institut français de recherche pour l'exploitation de la mer) |
op_collection_id |
ftarchimer |
language |
English |
topic |
climate variability Atlantic Ocean atmosphere-ocean general circulation models air-sea interactions Atlantic subpolar gyre Atlantic Meridional Overturning Circulation |
spellingShingle |
climate variability Atlantic Ocean atmosphere-ocean general circulation models air-sea interactions Atlantic subpolar gyre Atlantic Meridional Overturning Circulation Gastineau, Guillaume Mignot, Juliette Arzel, Olivier Huck, Thierry North Atlantic Ocean Internal Decadal Variability: Role of the Mean State and Ocean-Atmosphere Coupling |
topic_facet |
climate variability Atlantic Ocean atmosphere-ocean general circulation models air-sea interactions Atlantic subpolar gyre Atlantic Meridional Overturning Circulation |
description |
The origin of the decadal variability in the North Atlantic Ocean is investigated in a series of coupled and ocean-only numerical experiments. Two versions of the IPSL-CM5A model are considered, differing only by their atmospheric horizontal resolution (3.75 degrees x1.87 degrees and 2.5 degrees x1.25 degrees). When the ocean model is forced by the climatological surface fluxes from the low atmospheric resolution coupled model version, a 20-year variability emerges, similar to the variability found in the coupled simulation. Such decadal variability is consistent with a large-scale baroclinic instability of the mean flow in the west European basin. Increasing the atmospheric resolution leads to a more intense Icelandic low, which intensifies the western subpolar gyre, and warms the eastern North Atlantic subpolar gyre region. The mean state changes nearly vanish the associated internal oceanic variability under the corresponding climatological surface fluxes. Increasing the atmospheric resolution also produces a slightly weaker atmospheric stochastic forcing. Both the mean state and atmospheric variability changes are consistent with the decreasing amplitude of the variability in the coupled model. For both model versions, the amplitude of the internal oceanic variability is strongly enhanced in the presence of atmospheric stochastic forcing. Air-sea coupling on the other hand has a moderate influence on the amplitude of the variability only in the low-resolution model version, where the North Atlantic oceanic variability at 20years increases by 23% due to coupling. The coupling effect is therefore modest and sensitive to the atmospheric horizontal resolution. |
format |
Article in Journal/Newspaper |
author |
Gastineau, Guillaume Mignot, Juliette Arzel, Olivier Huck, Thierry |
author_facet |
Gastineau, Guillaume Mignot, Juliette Arzel, Olivier Huck, Thierry |
author_sort |
Gastineau, Guillaume |
title |
North Atlantic Ocean Internal Decadal Variability: Role of the Mean State and Ocean-Atmosphere Coupling |
title_short |
North Atlantic Ocean Internal Decadal Variability: Role of the Mean State and Ocean-Atmosphere Coupling |
title_full |
North Atlantic Ocean Internal Decadal Variability: Role of the Mean State and Ocean-Atmosphere Coupling |
title_fullStr |
North Atlantic Ocean Internal Decadal Variability: Role of the Mean State and Ocean-Atmosphere Coupling |
title_full_unstemmed |
North Atlantic Ocean Internal Decadal Variability: Role of the Mean State and Ocean-Atmosphere Coupling |
title_sort |
north atlantic ocean internal decadal variability: role of the mean state and ocean-atmosphere coupling |
publisher |
Amer Geophysical Union |
publishDate |
2018 |
url |
https://archimer.ifremer.fr/doc/00462/57374/59434.pdf https://archimer.ifremer.fr/doc/00462/57374/59435.pdf https://doi.org/10.1029/2018JC014074 https://archimer.ifremer.fr/doc/00462/57374/ |
long_lat |
ENVELOPE(-28.000,-28.000,52.750,52.750) |
geographic |
West European Basin |
geographic_facet |
West European Basin |
genre |
North Atlantic |
genre_facet |
North Atlantic |
op_source |
Journal Of Geophysical Research-oceans (2169-9275) (Amer Geophysical Union), 2018-08 , Vol. 123 , N. 8 , P. 5949-5970 |
op_relation |
info:eu-repo/grantAgreement/EC/FP7/312979/EU//IS-ENES2 https://archimer.ifremer.fr/doc/00462/57374/59434.pdf https://archimer.ifremer.fr/doc/00462/57374/59435.pdf doi:10.1029/2018JC014074 https://archimer.ifremer.fr/doc/00462/57374/ |
op_rights |
info:eu-repo/semantics/openAccess restricted use |
op_doi |
https://doi.org/10.1029/2018JC014074 |
container_title |
Journal of Geophysical Research: Oceans |
container_volume |
123 |
container_issue |
8 |
container_start_page |
5949 |
op_container_end_page |
5970 |
_version_ |
1766121346021982208 |