Variability of the Atlantic meridional overturning circulation in CCSM4
Atlantic meridional overturning circulation (AMOC) variability is documented in the Community Climate System Model, version 4 (CCSM4) preindustrial control simulation that uses nominal 1° horizontal resolution in all its components. AMOC shows a broad spectrum of low-frequency variability covering t...
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American Meteorological Society
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ftncar:oai:drupal-site.org:articles_12191 2023-09-05T13:20:54+02:00 Variability of the Atlantic meridional overturning circulation in CCSM4 Danabasoglu, Gokhan (author) Yeager, Stephen (author) Kwon, Young-Oh (author) Tribbia, Joseph (author) Phillips, Adam (author) Hurrell, James (author) 2012-08 application/pdf http://nldr.library.ucar.edu/repository/collections/OSGC-000-000-011-052 https://doi.org/10.1175/JCLI-D-11-00463.1 en eng American Meteorological Society Journal of Climate http://nldr.library.ucar.edu/repository/collections/OSGC-000-000-011-052 doi:10.1175/JCLI-D-11-00463.1 ark:/85065/d7bg2pqh Copyright 2012 American Meteorological Society (AMS). Permission to use figures, tables, and brief excerpts from this work in scientific and educational works is hereby granted provided that the source is acknowledged. Any use of material in this work that is determined to be "fair use" under Section 107 or that satisfies the conditions specified in Section 108 of the U.S. Copyright Law (17 USC, as revised by P.L. 94-553) does not require the Society's permission. Republication, systematic reproduction, posting in electronic form on servers, or other uses of this material, except as exempted by the above statements, requires written permission or license from the AMS. Additional details are provided in the AMS Copyright Policies, available from the AMS at 617-227-2425 or amspubs@ametsoc.org. Permission to place a copy of this work on this server has been provided by the AMS. The AMS does not guarantee that the copy provided here is an accurate copy of the published work. Text article 2012 ftncar https://doi.org/10.1175/JCLI-D-11-00463.1 2023-08-14T18:40:36Z Atlantic meridional overturning circulation (AMOC) variability is documented in the Community Climate System Model, version 4 (CCSM4) preindustrial control simulation that uses nominal 1° horizontal resolution in all its components. AMOC shows a broad spectrum of low-frequency variability covering the 50-200-yr range, contrasting sharply with the multidecadal variability seen in the T85 × 1 resolution CCSM3 present-day control simulation. Furthermore, the amplitude of variability is much reduced in CCSM4 compared to that of CCSM3. Similarities as well as differences in AMOC variability mechanisms between CCSM3 and CCSM4 are discussed. As in CCSM3, the CCSM4 AMOC variability is primarily driven by the positive density anomalies at the Labrador Sea (LS) deep-water formation site, peaking 2 yr prior to an AMOC maximum. All processes, including parameterized mesoscale and submesoscale eddies, play a role in the creation of salinity anomalies that dominate these density anomalies. High Nordic Sea densities do not necessarily lead to increased overflow transports because the overflow physics is governed by source and interior region density differences. Increased overflow transports do not lead to a higher AMOC either but instead appear to be a precursor to lower AMOC transports through enhanced stratification in LS. This has important implications for decadal prediction studies. The North Atlantic Oscillation (NAO) is significantly correlated with the positive boundary layer depth and density anomalies prior to an AMOC maximum. This suggests a role for NAO through setting the surface flux anomalies in LS and affecting the subpolar gyre circulation strength. Article in Journal/Newspaper Labrador Sea Nordic Sea North Atlantic North Atlantic oscillation OpenSky (NCAR/UCAR - National Center for Atmospheric Research/University Corporation for Atmospheric Research) Journal of Climate 25 15 5153 5172 |
institution |
Open Polar |
collection |
OpenSky (NCAR/UCAR - National Center for Atmospheric Research/University Corporation for Atmospheric Research) |
op_collection_id |
ftncar |
language |
English |
description |
Atlantic meridional overturning circulation (AMOC) variability is documented in the Community Climate System Model, version 4 (CCSM4) preindustrial control simulation that uses nominal 1° horizontal resolution in all its components. AMOC shows a broad spectrum of low-frequency variability covering the 50-200-yr range, contrasting sharply with the multidecadal variability seen in the T85 × 1 resolution CCSM3 present-day control simulation. Furthermore, the amplitude of variability is much reduced in CCSM4 compared to that of CCSM3. Similarities as well as differences in AMOC variability mechanisms between CCSM3 and CCSM4 are discussed. As in CCSM3, the CCSM4 AMOC variability is primarily driven by the positive density anomalies at the Labrador Sea (LS) deep-water formation site, peaking 2 yr prior to an AMOC maximum. All processes, including parameterized mesoscale and submesoscale eddies, play a role in the creation of salinity anomalies that dominate these density anomalies. High Nordic Sea densities do not necessarily lead to increased overflow transports because the overflow physics is governed by source and interior region density differences. Increased overflow transports do not lead to a higher AMOC either but instead appear to be a precursor to lower AMOC transports through enhanced stratification in LS. This has important implications for decadal prediction studies. The North Atlantic Oscillation (NAO) is significantly correlated with the positive boundary layer depth and density anomalies prior to an AMOC maximum. This suggests a role for NAO through setting the surface flux anomalies in LS and affecting the subpolar gyre circulation strength. |
author2 |
Danabasoglu, Gokhan (author) Yeager, Stephen (author) Kwon, Young-Oh (author) Tribbia, Joseph (author) Phillips, Adam (author) Hurrell, James (author) |
format |
Article in Journal/Newspaper |
title |
Variability of the Atlantic meridional overturning circulation in CCSM4 |
spellingShingle |
Variability of the Atlantic meridional overturning circulation in CCSM4 |
title_short |
Variability of the Atlantic meridional overturning circulation in CCSM4 |
title_full |
Variability of the Atlantic meridional overturning circulation in CCSM4 |
title_fullStr |
Variability of the Atlantic meridional overturning circulation in CCSM4 |
title_full_unstemmed |
Variability of the Atlantic meridional overturning circulation in CCSM4 |
title_sort |
variability of the atlantic meridional overturning circulation in ccsm4 |
publisher |
American Meteorological Society |
publishDate |
2012 |
url |
http://nldr.library.ucar.edu/repository/collections/OSGC-000-000-011-052 https://doi.org/10.1175/JCLI-D-11-00463.1 |
genre |
Labrador Sea Nordic Sea North Atlantic North Atlantic oscillation |
genre_facet |
Labrador Sea Nordic Sea North Atlantic North Atlantic oscillation |
op_relation |
Journal of Climate http://nldr.library.ucar.edu/repository/collections/OSGC-000-000-011-052 doi:10.1175/JCLI-D-11-00463.1 ark:/85065/d7bg2pqh |
op_rights |
Copyright 2012 American Meteorological Society (AMS). Permission to use figures, tables, and brief excerpts from this work in scientific and educational works is hereby granted provided that the source is acknowledged. Any use of material in this work that is determined to be "fair use" under Section 107 or that satisfies the conditions specified in Section 108 of the U.S. Copyright Law (17 USC, as revised by P.L. 94-553) does not require the Society's permission. Republication, systematic reproduction, posting in electronic form on servers, or other uses of this material, except as exempted by the above statements, requires written permission or license from the AMS. Additional details are provided in the AMS Copyright Policies, available from the AMS at 617-227-2425 or amspubs@ametsoc.org. Permission to place a copy of this work on this server has been provided by the AMS. The AMS does not guarantee that the copy provided here is an accurate copy of the published work. |
op_doi |
https://doi.org/10.1175/JCLI-D-11-00463.1 |
container_title |
Journal of Climate |
container_volume |
25 |
container_issue |
15 |
container_start_page |
5153 |
op_container_end_page |
5172 |
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1776201516505366528 |