Multimodel analysis on the response of the AMOC under an increase of radiative forcing and its symmetrical reversal

Verfasser / Beitragende:
[Giovanni Sgubin, Didier Swingedouw, Sybren Drijfhout, Stefan Hagemann, Eddy Robertson]
Ort, Verlag, Jahr:
2015
Enthalten in:
Climate Dynamics, 45/5-6(2015-09-01), 1429-1450
Format:
Artikel (online)
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024 7 0 |a 10.1007/s00382-014-2391-2  |2 doi 
035 |a (NATIONALLICENCE)springer-10.1007/s00382-014-2391-2 
245 0 0 |a Multimodel analysis on the response of the AMOC under an increase of radiative forcing and its symmetrical reversal  |h [Elektronische Daten]  |c [Giovanni Sgubin, Didier Swingedouw, Sybren Drijfhout, Stefan Hagemann, Eddy Robertson] 
520 3 |a The response of the Atlantic meridional overturning circulation (AMOC) to an increase of radiative forcing (ramp-up) and a subsequent reversal of radiative forcing (ramp-down) is analyzed for four different global climate models. Due to changes in ocean temperature and hydrological cycle, all models show a weakening of the AMOC during the ramp-up phase. Once the external forcing is reversed, the results become model dependent. For IPSL-CM5A-LR, the AMOC continues its weakening trend for most of the ramp-down experiment. For HadGEM2-ES, the AMOC trend reverses once the external forcing also reverses, without recovering its initial value. For EC-EARTH and MPI-ESM-LR the recovery is anomalously strong yielding an AMOC overshoot. A robust linear dependency can be established between AMOC and density difference between North Atlantic (NA) deep water formation region and South Atlantic (SA). In particular, AMOC evolution is primarily controlled by a meridional salinity contrast between these regions. During the warming scenario, the subtropical Atlantic becomes saltier while the NA experiences a net freshening which favours an AMOC weakening. The different behaviour in the models during the ramp-down is dependent on the response of the ocean at the boundaries of NA and SA. The way in which the positive salinity anomaly stored in the subtropical Atlantic during the ramp-up is subsequently released elsewhere, characterizes the recovery. An out-of-phase response of the salinity transport at $$48^{\circ }\hbox {N}$$ 48 ∘ N and $$34^{\circ }\hbox {S}$$ 34 ∘ S boundaries is able to control the meridional density contrast between NA and SA during the transient experiments. Such a non-synchronized response is mainly controlled by changes in gyre salinity transport rather than by changes in overturning transport, thus suggesting a small role of the salt advection feedback in the evolution of the AMOC. 
540 |a Springer-Verlag Berlin Heidelberg, 2014 
690 7 |a Climate modelling  |2 nationallicence 
690 7 |a Global warming  |2 nationallicence 
690 7 |a Atlantic meridional overturning circulation  |2 nationallicence 
690 7 |a AMOC stability  |2 nationallicence 
690 7 |a Salt advection feedback  |2 nationallicence 
690 7 |a Reversibility  |2 nationallicence 
700 1 |a Sgubin  |D Giovanni  |u Environnements et Paléoenvironnements Océaniques et Continentaux (EPOC), Bordeaux, France  |4 aut 
700 1 |a Swingedouw  |D Didier  |u Environnements et Paléoenvironnements Océaniques et Continentaux (EPOC), Bordeaux, France  |4 aut 
700 1 |a Drijfhout  |D Sybren  |u Royal Netherlands Meteorological Institute (KNMI), De Bilt, The Netherlands  |4 aut 
700 1 |a Hagemann  |D Stefan  |u Max Planck Institute for Meteorology (MPI-M), Hamburg, Germany  |4 aut 
700 1 |a Robertson  |D Eddy  |u Met Office Hadley Centre, Exeter, UK  |4 aut 
773 0 |t Climate Dynamics  |d Springer Berlin Heidelberg  |g 45/5-6(2015-09-01), 1429-1450  |x 0930-7575  |q 45:5-6<1429  |1 2015  |2 45  |o 382 
856 4 0 |u https://doi.org/10.1007/s00382-014-2391-2  |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/s00382-014-2391-2  |q text/html  |z Onlinezugriff via DOI 
950 |B NATIONALLICENCE  |P 700  |E 1-  |a Sgubin  |D Giovanni  |u Environnements et Paléoenvironnements Océaniques et Continentaux (EPOC), Bordeaux, France  |4 aut 
950 |B NATIONALLICENCE  |P 700  |E 1-  |a Swingedouw  |D Didier  |u Environnements et Paléoenvironnements Océaniques et Continentaux (EPOC), Bordeaux, France  |4 aut 
950 |B NATIONALLICENCE  |P 700  |E 1-  |a Drijfhout  |D Sybren  |u Royal Netherlands Meteorological Institute (KNMI), De Bilt, The Netherlands  |4 aut 
950 |B NATIONALLICENCE  |P 700  |E 1-  |a Hagemann  |D Stefan  |u Max Planck Institute for Meteorology (MPI-M), Hamburg, Germany  |4 aut 
950 |B NATIONALLICENCE  |P 700  |E 1-  |a Robertson  |D Eddy  |u Met Office Hadley Centre, Exeter, UK  |4 aut 
950 |B NATIONALLICENCE  |P 773  |E 0-  |t Climate Dynamics  |d Springer Berlin Heidelberg  |g 45/5-6(2015-09-01), 1429-1450  |x 0930-7575  |q 45:5-6<1429  |1 2015  |2 45  |o 382