Holocene variability in the North sub-Polar Gyre

• Main Authors: Pellichero, Violaine, Sicre, Marie-Alexandrine
• 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)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-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)-École polytechnique (X)-Centre National d'Études Spatiales Toulouse (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-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)-École polytechnique (X)-Centre National d'Études Spatiales Toulouse (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)
• Format: Conference Object
• Language: English
• Published: HAL CCSD 2015
• Subjects: [SDU.STU]Sciences of the Universe [physics]/Earth Sciences; [SDU.STU.CL]Sciences of the Universe [physics]/Earth Sciences/Climatology; Reykjanes; Ice Sheet; Iceland; Labrador Sea; North Atlantic
• Online Access: https://hal.science/hal-03503501

International audience The distribution of heat and moisture between low and high latitudes is for a large part controlled by the NorthAtlantic Ocean circulation and the dynamics of the sub-tropical (STG) and sub-polar gyre (SPG). Here, we present a new high-resolution (∼25 yrs) sea surface temperature (SST) reconstruction over the Holocene (last 10,000 years) in the subpolar North Atlantic. This time series was obtained by alkenone thermometry from the marine sediment core MD95-2015 located South of Iceland, on the eastern flank of the Reykjanes Ridge. Our data reveal three distinct time intervals corresponding to different sub-polar gyre circulation modes. A first period, in the Early Holocene, when the Laurentide ice sheet melting supplied fresh water in the Labrador Sea which contributed to stabilize vertical mixing; a second time period, ranging from ∼ 6500 yr BP to ∼3000 yr BP, during which the SPG was more active and vertical mixing more intense; a third one,encompassing the last millennia of the Late Holocene, when the gyre appeared to have narrowed and weakened. We compare our data with previous paleo-observations and discuss possible causes for these dynamical patterns of the SPG.