An event-based approach to understanding decadal fluctuations in the Atlantic meridional overturning circulation

Verfasser / Beitragende:
[Lesley Allison, Ed Hawkins, Tim Woollings]
Ort, Verlag, Jahr:
2015
Enthalten in:
Climate Dynamics, 44/1-2(2015-01-01), 163-190
Format:
Artikel (online)
ID: 605474257
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024 7 0 |a 10.1007/s00382-014-2271-9  |2 doi 
035 |a (NATIONALLICENCE)springer-10.1007/s00382-014-2271-9 
245 0 3 |a An event-based approach to understanding decadal fluctuations in the Atlantic meridional overturning circulation  |h [Elektronische Daten]  |c [Lesley Allison, Ed Hawkins, Tim Woollings] 
520 3 |a Many previous studies have shown that unforced climate model simulations exhibit decadal-scale fluctuations in the Atlantic meridional overturning circulation (AMOC), and that this variability can have impacts on surface climate fields. However, the robustness of these surface fingerprints across different models is less clear. Furthermore, with the potential for coupled feedbacks that may amplify or damp the response, it is not known whether the associated climate signals are linearly related to the strength of the AMOC changes, or if the fluctuation events exhibit nonlinear behaviour with respect to their strength or polarity. To explore these questions, we introduce an objective and flexible method for identifying the largest natural AMOC fluctuation events in multicentennial/multimillennial simulations of a variety of coupled climate models. The characteristics of the events are explored, including their magnitude, meridional coherence and spatial structure, as well as links with ocean heat transport and the horizontal circulation. The surface fingerprints in ocean temperature and salinity are examined, and compared with the results of linear regression analysis. It is found that the regressions generally provide a good indication of the surface changes associated with the largest AMOC events. However, there are some exceptions, including a nonlinear change in the atmospheric pressure signal, particularly at high latitudes, in HadCM3. Some asymmetries are also found between the changes associated with positive and negative AMOC events in the same model. Composite analysis suggests that there are signals that are robust across the largest AMOC events in each model, which provides reassurance that the surface changes associated with one particular event will be similar to those expected from regression analysis. However, large differences are found between the AMOC fingerprints in different models, which may hinder the prediction and attribution of such events in reality. 
540 |a Springer-Verlag Berlin Heidelberg, 2014 
690 7 |a Atlantic meridional overturning circulation  |2 nationallicence 
690 7 |a Thermohaline circulation  |2 nationallicence 
690 7 |a Decadal variability  |2 nationallicence 
690 7 |a Events  |2 nationallicence 
690 7 |a Nonlinear response  |2 nationallicence 
700 1 |a Allison  |D Lesley  |u NCAS-Climate, Department of Meteorology, University of Reading, Reading, UK  |4 aut 
700 1 |a Hawkins  |D Ed  |u NCAS-Climate, Department of Meteorology, University of Reading, Reading, UK  |4 aut 
700 1 |a Woollings  |D Tim  |u NCAS-Climate, Department of Meteorology, University of Reading, Reading, UK  |4 aut 
773 0 |t Climate Dynamics  |d Springer Berlin Heidelberg  |g 44/1-2(2015-01-01), 163-190  |x 0930-7575  |q 44:1-2<163  |1 2015  |2 44  |o 382 
856 4 0 |u https://doi.org/10.1007/s00382-014-2271-9  |q text/html  |z Onlinezugriff via DOI 
898 |a BK010053  |b XK010053  |c XK010000 
900 7 |a Metadata rights reserved  |b Springer special CC-BY-NC licence  |2 nationallicence 
908 |D 1  |a research-article  |2 jats 
949 |B NATIONALLICENCE  |F NATIONALLICENCE  |b NL-springer 
950 |B NATIONALLICENCE  |P 856  |E 40  |u https://doi.org/10.1007/s00382-014-2271-9  |q text/html  |z Onlinezugriff via DOI 
950 |B NATIONALLICENCE  |P 700  |E 1-  |a Allison  |D Lesley  |u NCAS-Climate, Department of Meteorology, University of Reading, Reading, UK  |4 aut 
950 |B NATIONALLICENCE  |P 700  |E 1-  |a Hawkins  |D Ed  |u NCAS-Climate, Department of Meteorology, University of Reading, Reading, UK  |4 aut 
950 |B NATIONALLICENCE  |P 700  |E 1-  |a Woollings  |D Tim  |u NCAS-Climate, Department of Meteorology, University of Reading, Reading, UK  |4 aut 
950 |B NATIONALLICENCE  |P 773  |E 0-  |t Climate Dynamics  |d Springer Berlin Heidelberg  |g 44/1-2(2015-01-01), 163-190  |x 0930-7575  |q 44:1-2<163  |1 2015  |2 44  |o 382