Response of the eastern North Atlantic subpolar gyre to the North Atlantic Oscillation

International audience The salinity changes in the subpolar gyre (SPG) in response to the North Atlantic Oscillation (NAO) are studied in idealized numerical experiments. In the eastern SPG, anomalies of similar amplitude as those observed during the 1995-1996 shift of the NAO are mainly driven by t...

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Bibliographic Details
Published in:Geophysical Research Letters
Main Authors: Herbaut, Christophe, Houssais, Marie-Noëlle
Other Authors: Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques (LOCEAN), Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS-PSL), Université Paris Sciences et Lettres (PSL)-Université Paris Sciences et Lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales Toulouse (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL), Université Paris Sciences et Lettres (PSL)-Université Paris Sciences et Lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales Toulouse (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)
Format: Article in Journal/Newspaper
Language:English
Published: HAL CCSD 2009
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Online Access:https://hal.science/hal-00760166
https://hal.science/hal-00760166/document
https://hal.science/hal-00760166/file/2009GL039090.pdf
https://doi.org/10.1029/2009GL039090
Description
Summary:International audience The salinity changes in the subpolar gyre (SPG) in response to the North Atlantic Oscillation (NAO) are studied in idealized numerical experiments. In the eastern SPG, anomalies of similar amplitude as those observed during the 1995-1996 shift of the NAO are mainly driven by the local response to the wind stress, through the set-up of an anticyclonic "intergyre" anomaly. In positive NAO, this anomalous circulation advects altogether (i) fresh, cold water from the western to the eastern SPG, contributing there to the formation of negative salinity anomalies, and (ii) warm, saline subtropical water to the south of Newfoundland, forming positive anomalies there. The latter are subsequently transported with the North Atlantic Current to the eastern SPG where they could act to weaken the low-salinity signal. The occurrence of this signal is concomitant with the acceleration of the gyre but, in contrast to earlier findings, is not subject to it.