Multiple Equilibria as a Possible Mechanism for Decadal Variability in the North Atlantic Ocean
Decadal climate variability in the North Atlantic has received increased attention in recent years, because modeling results suggest predictability of heat content and circulation indices several years ahead. However, determining the applicability of these results in the real world is challenging be...
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ftunivbern:oai:boris.unibe.ch:73874 2023-08-20T04:08:17+02:00 Multiple Equilibria as a Possible Mechanism for Decadal Variability in the North Atlantic Ocean Born, Andreas Mignot, Juliette Stocker, Thomas F. 2015 application/pdf https://boris.unibe.ch/73874/1/jcli-d-14-00813.1.pdf https://boris.unibe.ch/73874/ eng eng American Meteorological Society https://boris.unibe.ch/73874/ info:eu-repo/semantics/openAccess Born, Andreas; Mignot, Juliette; Stocker, Thomas F. (2015). Multiple Equilibria as a Possible Mechanism for Decadal Variability in the North Atlantic Ocean. Journal of Climate, 28(22), pp. 8907-8922. American Meteorological Society 10.1175/JCLI-D-14-00813.1 <http://dx.doi.org/10.1175/JCLI-D-14-00813.1> 530 Physics info:eu-repo/semantics/article info:eu-repo/semantics/publishedVersion PeerReviewed 2015 ftunivbern https://doi.org/10.1175/JCLI-D-14-00813.1 2023-07-31T21:21:15Z Decadal climate variability in the North Atlantic has received increased attention in recent years, because modeling results suggest predictability of heat content and circulation indices several years ahead. However, determining the applicability of these results in the real world is challenging because of an incomplete understanding of the underlying mechanisms. Here, the authors show that recent attempts to reconstruct the decadal variations in one of the dominant circulation systems of the region, the subpolar gyre (SPG), are not always consistent. A coherent picture is partly recovered by a simple conceptual model solely forced by reanalyzed surface air temperatures. This confirms that surface heat flux indeed plays a leading role for this type of variability, as has been suggested in previous studies. The results further suggest that large variations in the SPG correspond to the crossing of a bifurcation point that is predicted from idealized experiments and an analytical solution of the model used herein. Performance of this conceptual model is tested against a statistical stochastic model. Hysteresis and the existence of two stable modes of the SPG circulation shape its response to forcing by atmospheric temperatures. The identification of the essential dynamics and the reduction to a minimal model of SPG variability provide a quantifiable basis and a framework for future studies on decadal climate variability and predictability. Article in Journal/Newspaper North Atlantic BORIS (Bern Open Repository and Information System, University of Bern) Journal of Climate 28 22 8907 8922 |
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Open Polar |
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BORIS (Bern Open Repository and Information System, University of Bern) |
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ftunivbern |
language |
English |
topic |
530 Physics |
spellingShingle |
530 Physics Born, Andreas Mignot, Juliette Stocker, Thomas F. Multiple Equilibria as a Possible Mechanism for Decadal Variability in the North Atlantic Ocean |
topic_facet |
530 Physics |
description |
Decadal climate variability in the North Atlantic has received increased attention in recent years, because modeling results suggest predictability of heat content and circulation indices several years ahead. However, determining the applicability of these results in the real world is challenging because of an incomplete understanding of the underlying mechanisms. Here, the authors show that recent attempts to reconstruct the decadal variations in one of the dominant circulation systems of the region, the subpolar gyre (SPG), are not always consistent. A coherent picture is partly recovered by a simple conceptual model solely forced by reanalyzed surface air temperatures. This confirms that surface heat flux indeed plays a leading role for this type of variability, as has been suggested in previous studies. The results further suggest that large variations in the SPG correspond to the crossing of a bifurcation point that is predicted from idealized experiments and an analytical solution of the model used herein. Performance of this conceptual model is tested against a statistical stochastic model. Hysteresis and the existence of two stable modes of the SPG circulation shape its response to forcing by atmospheric temperatures. The identification of the essential dynamics and the reduction to a minimal model of SPG variability provide a quantifiable basis and a framework for future studies on decadal climate variability and predictability. |
format |
Article in Journal/Newspaper |
author |
Born, Andreas Mignot, Juliette Stocker, Thomas F. |
author_facet |
Born, Andreas Mignot, Juliette Stocker, Thomas F. |
author_sort |
Born, Andreas |
title |
Multiple Equilibria as a Possible Mechanism for Decadal Variability in the North Atlantic Ocean |
title_short |
Multiple Equilibria as a Possible Mechanism for Decadal Variability in the North Atlantic Ocean |
title_full |
Multiple Equilibria as a Possible Mechanism for Decadal Variability in the North Atlantic Ocean |
title_fullStr |
Multiple Equilibria as a Possible Mechanism for Decadal Variability in the North Atlantic Ocean |
title_full_unstemmed |
Multiple Equilibria as a Possible Mechanism for Decadal Variability in the North Atlantic Ocean |
title_sort |
multiple equilibria as a possible mechanism for decadal variability in the north atlantic ocean |
publisher |
American Meteorological Society |
publishDate |
2015 |
url |
https://boris.unibe.ch/73874/1/jcli-d-14-00813.1.pdf https://boris.unibe.ch/73874/ |
genre |
North Atlantic |
genre_facet |
North Atlantic |
op_source |
Born, Andreas; Mignot, Juliette; Stocker, Thomas F. (2015). Multiple Equilibria as a Possible Mechanism for Decadal Variability in the North Atlantic Ocean. Journal of Climate, 28(22), pp. 8907-8922. American Meteorological Society 10.1175/JCLI-D-14-00813.1 <http://dx.doi.org/10.1175/JCLI-D-14-00813.1> |
op_relation |
https://boris.unibe.ch/73874/ |
op_rights |
info:eu-repo/semantics/openAccess |
op_doi |
https://doi.org/10.1175/JCLI-D-14-00813.1 |
container_title |
Journal of Climate |
container_volume |
28 |
container_issue |
22 |
container_start_page |
8907 |
op_container_end_page |
8922 |
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1774720468652130304 |