Decadal variability of sea surface temperatures off North Iceland over the last 2000 years

• Published in: Earth and Planetary Science Letters
• Main Authors: Sicre, Marie Alexandrine, Jacob, Jérémy, Ezat, Ullah, Rousse, Sonia, Kissel, Catherine, Yiou, Pascal, Eiríksson, Jon, Knudsen, Karen Luise, Jansen, Eystein, Turon, Jean-Louis
• Other Authors: Paléocéanographie (PALEOCEAN), Laboratoire des Sciences du Climat et de l'Environnement Gif-sur-Yvette (LSCE), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Institut des Sciences de la Terre d'Orléans (ISTO), Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS), Climat et Magnétisme (CLIMAG), Extrèmes : Statistiques, Impacts et Régionalisation (ESTIMR), University of Iceland Reykjavik, Department of Earth Sciences Aarhus, Aarhus University Aarhus, Bjerknes Centre for Climate Research (BCCR), Department of Biological Sciences Bergen (BIO / UiB), University of Bergen (UiB)-University of Bergen (UiB), Departement de Géologie et Océanographie, Université Sciences et Technologies - Bordeaux 1 (UB), PACLIVA European Commission 5th Framework Program (Contract EVK2-2002-00143).
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2008
• Subjects: Decadal variability; Sea surface temperature; North Atlantic; Alkenones; Medieval Warm Period; Little Ice Age; Iceland; [SDU.STU.CL]Sciences of the Universe [physics]/Earth Sciences/Climatology; Denmark Strait; North Atlantic oscillation; Sea ice; NIIC
• Online Access: https://insu.hal.science/insu-00311666; https://insu.hal.science/insu-00311666/document; https://insu.hal.science/insu-00311666/file/Sicre_et_al_-_2008_-_EPSL.pdf; https://doi.org/10.1016/j.epsl.2008.01.011

International audience Ocean variability at decadal time-scales remains poorly described partly because of the scarcity of high temporal resolution marine records. Here, we present a reconstruction of Sea Surface Temperatures (SSTs) over the past twomillennia at unprecedented temporal resolution (2 to 5 years), from a marine core located off North Iceland. Alkenone paleothermometry was used to infer SST variability, and tephrochronology to build the age model. Spectral analyses of the SSTsignal indicate intermittent 20–25 year oscillations, with periods of strong and weak power, that are likely reflecting the ocean response to wind forcing, presumably the North Atlantic Oscillation (NAO). Warmer SSTs and paleo-magnetic proxy data, between 1000 and 1350 year A.D., overlapping theMedievalWarm Period (MWP), suggest enhanced heat transport across the Denmark Strait by the North Icelandic IrmingerCurrent (NIIC). This is in contrast with the subsequent period, which includes the Little IceAge (LIA), showing continuous cooling towards the 20th century.Reduced NIIC flow through theDenmark Strait likely resulting from higher freshwater and sea ice export from the Arctic would account for the observed colder conditions.