Simulated variability of the Atlantic meridional overturning circulation
To examine the multi-annual to decadal scale variability of the Atlantic Meridional Overturning Circulation (AMOC), a four-member ensemble with a daily reanalysis forced, medium-resolution global version of the isopycnic coordinate ocean model MICOM, and a 300-years integration with the fully couple...
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2004
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Online Access: | https://hdl.handle.net/1956/630 https://doi.org/10.1007/s00382-004-0397-x |
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ftunivbergen:oai:bora.uib.no:1956/630 2023-05-15T16:30:13+02:00 Simulated variability of the Atlantic meridional overturning circulation Bentsen, Mats Drange, Helge Furevik, Tore Zhou, Tianjun 2004-04-17 3022317 bytes application/pdf https://hdl.handle.net/1956/630 https://doi.org/10.1007/s00382-004-0397-x eng eng Springer Verlag urn:issn:0930-7575 https://hdl.handle.net/1956/630 https://doi.org/10.1007/s00382-004-0397-x Climate Dynamics. 2004, 22 (6/7): 701-720. Climate Dynamics 701-720 22 6/7 Journal article 2004 ftunivbergen https://doi.org/10.1007/s00382-004-0397-x 2023-03-14T17:41:44Z To examine the multi-annual to decadal scale variability of the Atlantic Meridional Overturning Circulation (AMOC), a four-member ensemble with a daily reanalysis forced, medium-resolution global version of the isopycnic coordinate ocean model MICOM, and a 300-years integration with the fully coupled Bergen Climate Model (BCM), have been conducted. The simulations of the AMOC with both model systems yield a long-term mean value of 18 Sv and decadal variability with an amplitude of 1–3 Sv. The power spectrum of the inter-annual to decadal scale variability of the AMOC in BCM generally follows the theoretical red noise spectrum, with indications of increased power near the 20-years period. Comparison with observational proxy indices for the AMOC, e.g. the thickness of the Labrador Sea Water, the strength of the baroclinic gyre circulation in the North Atlantic Ocean, and the surface temperature anomalies along the mean path of the Gulf Stream, shows similar trends and phasing of the variability, indicating that the simulated AMOC variability is robust and real. Mixing indices have been constructed for the Labrador, the Irminger and the Greenland-Iceland-Norwegian (GIN) Seas. While convective mixing in the Labrador and the GIN Seas are in opposite phase, and linked to the NAO as observations suggest, the convective mixing in the Irminger Sea is in phase with or leads the Labrador Sea. Newly formed deep water is seen as a slow, anomalous cold and fresh, plume flowing southward along the western continental slope of the Atlantic Ocean, with a return flow of warm and saline water in the surface. In addition, fasttravelling topographically-trapped waves propagate southward along the continental slope towards equator, where they go east and continue along the eastern rim of the Atlantic. For both types of experiments, the Northern Hemisphere sea level pressure and 2 m temperature anomaly patterns computed based on the difference between climate states with strong and weak AMOC yields a NAO-like pattern with intensified ... Article in Journal/Newspaper Greenland Iceland Labrador Sea North Atlantic University of Bergen: Bergen Open Research Archive (BORA-UiB) Bergen Greenland Irminger Sea ENVELOPE(-34.041,-34.041,63.054,63.054) Climate Dynamics 22 6-7 701 720 |
institution |
Open Polar |
collection |
University of Bergen: Bergen Open Research Archive (BORA-UiB) |
op_collection_id |
ftunivbergen |
language |
English |
description |
To examine the multi-annual to decadal scale variability of the Atlantic Meridional Overturning Circulation (AMOC), a four-member ensemble with a daily reanalysis forced, medium-resolution global version of the isopycnic coordinate ocean model MICOM, and a 300-years integration with the fully coupled Bergen Climate Model (BCM), have been conducted. The simulations of the AMOC with both model systems yield a long-term mean value of 18 Sv and decadal variability with an amplitude of 1–3 Sv. The power spectrum of the inter-annual to decadal scale variability of the AMOC in BCM generally follows the theoretical red noise spectrum, with indications of increased power near the 20-years period. Comparison with observational proxy indices for the AMOC, e.g. the thickness of the Labrador Sea Water, the strength of the baroclinic gyre circulation in the North Atlantic Ocean, and the surface temperature anomalies along the mean path of the Gulf Stream, shows similar trends and phasing of the variability, indicating that the simulated AMOC variability is robust and real. Mixing indices have been constructed for the Labrador, the Irminger and the Greenland-Iceland-Norwegian (GIN) Seas. While convective mixing in the Labrador and the GIN Seas are in opposite phase, and linked to the NAO as observations suggest, the convective mixing in the Irminger Sea is in phase with or leads the Labrador Sea. Newly formed deep water is seen as a slow, anomalous cold and fresh, plume flowing southward along the western continental slope of the Atlantic Ocean, with a return flow of warm and saline water in the surface. In addition, fasttravelling topographically-trapped waves propagate southward along the continental slope towards equator, where they go east and continue along the eastern rim of the Atlantic. For both types of experiments, the Northern Hemisphere sea level pressure and 2 m temperature anomaly patterns computed based on the difference between climate states with strong and weak AMOC yields a NAO-like pattern with intensified ... |
format |
Article in Journal/Newspaper |
author |
Bentsen, Mats Drange, Helge Furevik, Tore Zhou, Tianjun |
spellingShingle |
Bentsen, Mats Drange, Helge Furevik, Tore Zhou, Tianjun Simulated variability of the Atlantic meridional overturning circulation |
author_facet |
Bentsen, Mats Drange, Helge Furevik, Tore Zhou, Tianjun |
author_sort |
Bentsen, Mats |
title |
Simulated variability of the Atlantic meridional overturning circulation |
title_short |
Simulated variability of the Atlantic meridional overturning circulation |
title_full |
Simulated variability of the Atlantic meridional overturning circulation |
title_fullStr |
Simulated variability of the Atlantic meridional overturning circulation |
title_full_unstemmed |
Simulated variability of the Atlantic meridional overturning circulation |
title_sort |
simulated variability of the atlantic meridional overturning circulation |
publisher |
Springer Verlag |
publishDate |
2004 |
url |
https://hdl.handle.net/1956/630 https://doi.org/10.1007/s00382-004-0397-x |
long_lat |
ENVELOPE(-34.041,-34.041,63.054,63.054) |
geographic |
Bergen Greenland Irminger Sea |
geographic_facet |
Bergen Greenland Irminger Sea |
genre |
Greenland Iceland Labrador Sea North Atlantic |
genre_facet |
Greenland Iceland Labrador Sea North Atlantic |
op_source |
Climate Dynamics 701-720 22 6/7 |
op_relation |
urn:issn:0930-7575 https://hdl.handle.net/1956/630 https://doi.org/10.1007/s00382-004-0397-x Climate Dynamics. 2004, 22 (6/7): 701-720. |
op_doi |
https://doi.org/10.1007/s00382-004-0397-x |
container_title |
Climate Dynamics |
container_volume |
22 |
container_issue |
6-7 |
container_start_page |
701 |
op_container_end_page |
720 |
_version_ |
1766019927931617280 |