Comparing observed and modelled components of the Atlantic Meridional Overturning Circulation at 26°N
The Coupled Model Intercomparison Project (CMIP) allows assessment of the representation of the Atlantic Meridional Overturning Circulation (AMOC) in climate models. While CMIP Phase 6 models display a large spread in AMOC strength by a factor of three, the multi-model mean strength agrees reasonabl...
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Copernicus Publications
2023
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ftnonlinearchiv:oai:noa.gwlb.de:cop_mods_00069911 2023-12-17T10:20:29+01:00 Comparing observed and modelled components of the Atlantic Meridional Overturning Circulation at 26°N Bryden, Harry Drijfhout, Sybren Mecking, Jennifer Hazeleger, Wilco 2023-11 electronic https://doi.org/10.5194/egusphere-2023-2688 https://noa.gwlb.de/receive/cop_mods_00069911 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00068279/egusphere-2023-2688.pdf https://egusphere.copernicus.org/preprints/2023/egusphere-2023-2688/egusphere-2023-2688.pdf eng eng Copernicus Publications https://doi.org/10.5194/egusphere-2023-2688 https://noa.gwlb.de/receive/cop_mods_00069911 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00068279/egusphere-2023-2688.pdf https://egusphere.copernicus.org/preprints/2023/egusphere-2023-2688/egusphere-2023-2688.pdf https://creativecommons.org/licenses/by/4.0/ uneingeschränkt info:eu-repo/semantics/openAccess article Verlagsveröffentlichung article Text doc-type:article 2023 ftnonlinearchiv https://doi.org/10.5194/egusphere-2023-2688 2023-11-20T00:22:45Z The Coupled Model Intercomparison Project (CMIP) allows assessment of the representation of the Atlantic Meridional Overturning Circulation (AMOC) in climate models. While CMIP Phase 6 models display a large spread in AMOC strength by a factor of three, the multi-model mean strength agrees reasonably well with observed estimates from RAPID1, but this does not hold for its various components. In CMIP6 the present-day AMOC is characterised by a lack of lower North Atlantic Deep Water (lNADW), due to the small-scale of Greenland-Iceland-Scotland Ridge overflow and too much mixing. This is compensated by increased recirculation in the subtropical gyre and more Antarctic Bottom Water (AABW). Deep-water circulation is dominated by a distinct deep western boundary current (DWBC) with minor interior recirculation compared to observations. The future decline in the AMOC to 2100 of 7 Sv under a SSP5-8.5 scenario is associated with decreased northward western boundary current transport in combination with reduced southward flow of upper North Atlantic Deep Water (uNADW). In CMIP6, wind stress curl decreases with time by 14 % so that the wind-driven thermocline recirculation in the subtropical gyre is reduced by 4 Sv (17 %) by 2100. The reduction in western boundary current transport of 11 Sv is more than the decrease in the wind-driven gyre transport suggesting a decrease over time in the component of the Gulf Stream originating in the South Atlantic. 1 RAPID is used here as shorthand for the RAPID-Meridional Overturning Circulation and Heatflux Array-Western Boundary Time Series at 26°N (Moat et al., 2022). Article in Journal/Newspaper Antarc* Antarctic Greenland Iceland North Atlantic Deep Water North Atlantic Niedersächsisches Online-Archiv NOA Antarctic Greenland Curl ENVELOPE(-63.071,-63.071,-70.797,-70.797) |
institution |
Open Polar |
collection |
Niedersächsisches Online-Archiv NOA |
op_collection_id |
ftnonlinearchiv |
language |
English |
topic |
article Verlagsveröffentlichung |
spellingShingle |
article Verlagsveröffentlichung Bryden, Harry Drijfhout, Sybren Mecking, Jennifer Hazeleger, Wilco Comparing observed and modelled components of the Atlantic Meridional Overturning Circulation at 26°N |
topic_facet |
article Verlagsveröffentlichung |
description |
The Coupled Model Intercomparison Project (CMIP) allows assessment of the representation of the Atlantic Meridional Overturning Circulation (AMOC) in climate models. While CMIP Phase 6 models display a large spread in AMOC strength by a factor of three, the multi-model mean strength agrees reasonably well with observed estimates from RAPID1, but this does not hold for its various components. In CMIP6 the present-day AMOC is characterised by a lack of lower North Atlantic Deep Water (lNADW), due to the small-scale of Greenland-Iceland-Scotland Ridge overflow and too much mixing. This is compensated by increased recirculation in the subtropical gyre and more Antarctic Bottom Water (AABW). Deep-water circulation is dominated by a distinct deep western boundary current (DWBC) with minor interior recirculation compared to observations. The future decline in the AMOC to 2100 of 7 Sv under a SSP5-8.5 scenario is associated with decreased northward western boundary current transport in combination with reduced southward flow of upper North Atlantic Deep Water (uNADW). In CMIP6, wind stress curl decreases with time by 14 % so that the wind-driven thermocline recirculation in the subtropical gyre is reduced by 4 Sv (17 %) by 2100. The reduction in western boundary current transport of 11 Sv is more than the decrease in the wind-driven gyre transport suggesting a decrease over time in the component of the Gulf Stream originating in the South Atlantic. 1 RAPID is used here as shorthand for the RAPID-Meridional Overturning Circulation and Heatflux Array-Western Boundary Time Series at 26°N (Moat et al., 2022). |
format |
Article in Journal/Newspaper |
author |
Bryden, Harry Drijfhout, Sybren Mecking, Jennifer Hazeleger, Wilco |
author_facet |
Bryden, Harry Drijfhout, Sybren Mecking, Jennifer Hazeleger, Wilco |
author_sort |
Bryden, Harry |
title |
Comparing observed and modelled components of the Atlantic Meridional Overturning Circulation at 26°N |
title_short |
Comparing observed and modelled components of the Atlantic Meridional Overturning Circulation at 26°N |
title_full |
Comparing observed and modelled components of the Atlantic Meridional Overturning Circulation at 26°N |
title_fullStr |
Comparing observed and modelled components of the Atlantic Meridional Overturning Circulation at 26°N |
title_full_unstemmed |
Comparing observed and modelled components of the Atlantic Meridional Overturning Circulation at 26°N |
title_sort |
comparing observed and modelled components of the atlantic meridional overturning circulation at 26°n |
publisher |
Copernicus Publications |
publishDate |
2023 |
url |
https://doi.org/10.5194/egusphere-2023-2688 https://noa.gwlb.de/receive/cop_mods_00069911 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00068279/egusphere-2023-2688.pdf https://egusphere.copernicus.org/preprints/2023/egusphere-2023-2688/egusphere-2023-2688.pdf |
long_lat |
ENVELOPE(-63.071,-63.071,-70.797,-70.797) |
geographic |
Antarctic Greenland Curl |
geographic_facet |
Antarctic Greenland Curl |
genre |
Antarc* Antarctic Greenland Iceland North Atlantic Deep Water North Atlantic |
genre_facet |
Antarc* Antarctic Greenland Iceland North Atlantic Deep Water North Atlantic |
op_relation |
https://doi.org/10.5194/egusphere-2023-2688 https://noa.gwlb.de/receive/cop_mods_00069911 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00068279/egusphere-2023-2688.pdf https://egusphere.copernicus.org/preprints/2023/egusphere-2023-2688/egusphere-2023-2688.pdf |
op_rights |
https://creativecommons.org/licenses/by/4.0/ uneingeschränkt info:eu-repo/semantics/openAccess |
op_doi |
https://doi.org/10.5194/egusphere-2023-2688 |
_version_ |
1785522626582544384 |