Trends and centennial-scale variability of surface water temperatures in the North Atlantic during the Holocene

• Published in: Quaternary Science Reviews
• Main Authors: Sicre, Marie-Alexandrine, Jalali, Bassem, Eiríksson, Jón, Knudsen, Karen-Luise, Klein, Vincent, Pellichero, Violaine
• Other Authors: Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques (LOCEAN), Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS Paris), 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 de Paris (UP)-École normale supérieure - Paris (ENS Paris), 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 de Paris (UP)-Institut de Recherche pour le Développement (IRD)-Muséum national d'Histoire naturelle (MNHN)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2021
• Subjects: Holocene; Sea Surface Temperature; subpolar gyre; North Atlantic Alkenones; SST; North Atlantic; subpolar gyre circulation; [SDE.MCG]Environmental Sciences/Global Changes; [SDU.STU.CL]Sciences of the Universe [physics]/Earth Sciences/Climatology; [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography; Dee; Reykjanes; Iceland; Nordic Seas
• Online Access: https://hal.archives-ouvertes.fr/hal-03414570; https://hal.archives-ouvertes.fr/hal-03414570/document; https://hal.archives-ouvertes.fr/hal-03414570/file/Sicre%20et%20al.%20accepted.pdf; https://doi.org/10.1016/j.quascirev.2021.107033

International audience Two sediment cores retrieved off North Iceland (western Nordic Seas) and on the eastern flank of Reykjanes Ridge (Iceland Basin) were analyzed to generate high-resolution alkenone-derived sea surface temperature (SST) records to investigate North Atlantic Ocean circulation changes during the Holocene. Early Holocene SSTs off North Iceland were unstable (10+1°C) and 3°C warmer than today reflecting active northward heat transport of the Atlantic Meridional Overturning Circulation (AMOC) interrupted by intermittent Polar Waters incursions onto the North Icelandic shelf. The Holocene thermal optimum occurred synchronously East of Reykjanes Ridge, with a mean value of 11.5°C (+0.5°C) similar to today, consistent with a sustained influence of AMOC. Both records indicate that the circulation across the North Atlantic intensified between 8000 and 7000 yr BP. Thereafter, SSTs in the two basin sites broadly depict opposing trends and centennial-scale oscillations and a notable cooling at ~5300 yr BP that coincides with Bond 4 event and the temporary collapse of the dee-water circulation. From 2500 yr BP onwards, SSTs in the Iceland basin and the western Nordic Seas diverge leading to a marked cooling/warming dipole resulting in a temperature difference today of 4.5°C. We show that SST trends and centennial-scale variability reflect variations of the subpolar gyre (SPG) circulation linked to drifting ice events and convection changes in the Labrador and Nordic Seas.