Atmospheric conditions associated with Labrador Sea deep convection: New insights from a case study of the 2006/07 and 2007/08 winters
Deep convection in the Labrador Sea (LS) resumed in the winter of 2007/08 under a moderately positive North Atlantic Oscillation (NAO) state. This is in sharp contrast with the previous winter with weak convection, despite a similar positive NAO state. This disparity is explored here by analyzing re...
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ftncar:oai:drupal-site.org:articles_18604 2023-09-05T13:20:54+02:00 Atmospheric conditions associated with Labrador Sea deep convection: New insights from a case study of the 2006/07 and 2007/08 winters Kim, Who (author) Yeager, Stephen (author) Chang, Ping (author) Danabasoglu, Gokhan (author) 2016-07-15 application/pdf http://nldr.library.ucar.edu/repository/collections/OSGC-000-000-023-062 https://doi.org/10.1175/JCLI-D-15-0527.1 en eng American Meteorological Society Journal of Climate articles:18604 ark:/85065/d7h996tj http://nldr.library.ucar.edu/repository/collections/OSGC-000-000-023-062 doi:10.1175/JCLI-D-15-0527.1 Copyright 2016 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 2016 ftncar https://doi.org/10.1175/JCLI-D-15-0527.1 2023-08-14T18:43:50Z Deep convection in the Labrador Sea (LS) resumed in the winter of 2007/08 under a moderately positive North Atlantic Oscillation (NAO) state. This is in sharp contrast with the previous winter with weak convection, despite a similar positive NAO state. This disparity is explored here by analyzing reanalysis data and forced-ocean simulations. It is found that the difference in deep convection is primarily due to differences in large-scale atmospheric conditions that are not accounted for by the conventional NAO definition. Specifically, the 2007/08 winter was characterized by an atmospheric circulation anomaly centered in the western North Atlantic, rather than the eastern North Atlantic that the conventional NAO emphasizes. This anomalous circulation was also accompanied by anomalously cold conditions over northern North America. The controlling influence of these atmospheric conditions on LS deep convection in the 2008 winter is confirmed by sensitivity experiments where surface forcing and/or initial conditions are modified. An extended analysis for the 1949-2009 period shows that about half of the winters with strong heat losses in the LS are associated with such a west-centered circulation anomaly and cold conditions over northern North America. These are found to be accompanied by La Niña-like conditions in the tropical Pacific, suggesting that the atmospheric response to La Niña may have a strong influence on LS deep convection. OCE1243015 Article in Journal/Newspaper Labrador Sea North Atlantic North Atlantic oscillation OpenSky (NCAR/UCAR - National Center for Atmospheric Research/University Corporation for Atmospheric Research) Pacific Journal of Climate 29 14 5281 5297 |
institution |
Open Polar |
collection |
OpenSky (NCAR/UCAR - National Center for Atmospheric Research/University Corporation for Atmospheric Research) |
op_collection_id |
ftncar |
language |
English |
description |
Deep convection in the Labrador Sea (LS) resumed in the winter of 2007/08 under a moderately positive North Atlantic Oscillation (NAO) state. This is in sharp contrast with the previous winter with weak convection, despite a similar positive NAO state. This disparity is explored here by analyzing reanalysis data and forced-ocean simulations. It is found that the difference in deep convection is primarily due to differences in large-scale atmospheric conditions that are not accounted for by the conventional NAO definition. Specifically, the 2007/08 winter was characterized by an atmospheric circulation anomaly centered in the western North Atlantic, rather than the eastern North Atlantic that the conventional NAO emphasizes. This anomalous circulation was also accompanied by anomalously cold conditions over northern North America. The controlling influence of these atmospheric conditions on LS deep convection in the 2008 winter is confirmed by sensitivity experiments where surface forcing and/or initial conditions are modified. An extended analysis for the 1949-2009 period shows that about half of the winters with strong heat losses in the LS are associated with such a west-centered circulation anomaly and cold conditions over northern North America. These are found to be accompanied by La Niña-like conditions in the tropical Pacific, suggesting that the atmospheric response to La Niña may have a strong influence on LS deep convection. OCE1243015 |
author2 |
Kim, Who (author) Yeager, Stephen (author) Chang, Ping (author) Danabasoglu, Gokhan (author) |
format |
Article in Journal/Newspaper |
title |
Atmospheric conditions associated with Labrador Sea deep convection: New insights from a case study of the 2006/07 and 2007/08 winters |
spellingShingle |
Atmospheric conditions associated with Labrador Sea deep convection: New insights from a case study of the 2006/07 and 2007/08 winters |
title_short |
Atmospheric conditions associated with Labrador Sea deep convection: New insights from a case study of the 2006/07 and 2007/08 winters |
title_full |
Atmospheric conditions associated with Labrador Sea deep convection: New insights from a case study of the 2006/07 and 2007/08 winters |
title_fullStr |
Atmospheric conditions associated with Labrador Sea deep convection: New insights from a case study of the 2006/07 and 2007/08 winters |
title_full_unstemmed |
Atmospheric conditions associated with Labrador Sea deep convection: New insights from a case study of the 2006/07 and 2007/08 winters |
title_sort |
atmospheric conditions associated with labrador sea deep convection: new insights from a case study of the 2006/07 and 2007/08 winters |
publisher |
American Meteorological Society |
publishDate |
2016 |
url |
http://nldr.library.ucar.edu/repository/collections/OSGC-000-000-023-062 https://doi.org/10.1175/JCLI-D-15-0527.1 |
geographic |
Pacific |
geographic_facet |
Pacific |
genre |
Labrador Sea North Atlantic North Atlantic oscillation |
genre_facet |
Labrador Sea North Atlantic North Atlantic oscillation |
op_relation |
Journal of Climate articles:18604 ark:/85065/d7h996tj http://nldr.library.ucar.edu/repository/collections/OSGC-000-000-023-062 doi:10.1175/JCLI-D-15-0527.1 |
op_rights |
Copyright 2016 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-15-0527.1 |
container_title |
Journal of Climate |
container_volume |
29 |
container_issue |
14 |
container_start_page |
5281 |
op_container_end_page |
5297 |
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1776201514185916416 |