Publications des scientifiques de l'IRD

Ba J., Keenlyside N. S., Latif M., Park W., Ding H., Lohmann K., Mignot Juliette, Menary M., Ottera O. H., Wouters B., Melia D. S. Y., Oka A., Bellucci A., Volodin E. (2014). A multi-model comparison of Atlantic multidecadal variability. Climate Dynamics, 43 (9-10), p. 2333-2348. ISSN 0930-7575.

Titre du document
A multi-model comparison of Atlantic multidecadal variability
Année de publication
2014
Type de document
Article référencé dans le Web of Science WOS:000344480100002
Auteurs
Ba J., Keenlyside N. S., Latif M., Park W., Ding H., Lohmann K., Mignot Juliette, Menary M., Ottera O. H., Wouters B., Melia D. S. Y., Oka A., Bellucci A., Volodin E.
Source
Climate Dynamics, 2014, 43 (9-10), p. 2333-2348 ISSN 0930-7575
A multi-model analysis of Atlantic multidecadal variability is performed with the following aims: to investigate the similarities to observations; to assess the strength and relative importance of the different elements of the mechanism proposed by Delworth et al. (J Clim 6: 1993-2011, 1993) (hereafter D93) among coupled general circulation models (CGCMs); and to relate model differences to mean systematic error. The analysis is performed with long control simulations from ten CGCMs, with lengths ranging between 500 and 3600 years. In most models the variations of sea surface temperature (SST) averaged over North Atlantic show considerable power on multidecadal time scales, but with different periodicity. The SST variations are largest in the mid-latitude region, consistent with the short instrumental record. Despite large differences in model configurations, we find quite some consistency among the models in terms of processes. In eight of the ten models the mid-latitude SST variations are significantly correlated with fluctuations in the Atlantic meridional overturning circulation (AMOC), suggesting a link to northward heat transport changes. Consistent with this link, the three models with the weakest AMOC have the largest cold SST bias in the North Atlantic. There is no linear relationship on decadal timescales between AMOC and North Atlantic Oscillation in the models. Analysis of the key elements of the D93 mechanisms revealed the following: Most models present strong evidence that highlatitude winter mixing precede AMOC changes. However, the regions of wintertime convection differ among models. In most models salinity-induced density anomalies in the convective region tend to lead AMOC, while temperatureinduced density anomalies lead AMOC only in one model. However, analysis shows that salinity may play an overly important role in most models, because of cold temperature biases in their relevant convective regions. In most models subpolar gyre variations tend to lead AMOC changes, and this relation is strong in more than half of the models.
Plan de classement
Sciences fondamentales / Techniques d'analyse et de recherche [020] ; Sciences du milieu [021] ; Limnologie physique / Océanographie physique [032]
Description Géographique
ATLANTIQUE
Localisation
Fonds IRD [F B010062699]
Identifiant IRD
fdi:010062699
Contact