Interannual variability in tropical Pacific temperatures during Heinrich stadial 1

• Main Authors: Felis, T., Merkel, U., Asami, R., Deschamps, Pierre, Hathorne, E., Koelling, M., Bard, Edouard, Cabioch, Guy, Durand, N., Prange, M., Schulz, M., Cahyarini, S., Pfeiffer, M.
• Other Authors: Center for Marine Environmental Sciences Bremen (MARUM), Universität Bremen, University of the Ryukyus Okinawa, Centre européen de recherche et d'enseignement des géosciences de l'environnement (CEREGE), Institut de Recherche pour le Développement (IRD)-Institut National de la Recherche Agronomique (INRA)-Aix Marseille Université (AMU)-Collège de France (CdF (institution))-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), 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), Leibniz Institute of Marine Science at the University of Kiel (IFM-GEOMAR), Christian-Albrechts-Universität zu Kiel = Christian-Albrechts University of Kiel = Université Christian-Albrechts de Kiel (CAU)
• Format: Conference Object
• Language: English
• Published: HAL CCSD 2009
• Subjects: 4916 PALEOCEANOGRAPHY / Corals; 4922 PALEOCEANOGRAPHY / El Nino; 4926 PALEOCEANOGRAPHY / Glacial; 4928 PALEOCEANOGRAPHY / Global climate models; [SDU]Sciences of the Universe [physics]; North Atlantic
• Online Access: https://hal.science/hal-04113496

International audience Assessing the response of interannual climate variability in the tropical Pacific Ocean to future greenhouse warming is of paramount importance. However, the dominant mode of Pacific atmosphere-ocean variability on interannual timescales, the El Niño-Southern Oscillation (ENSO), is poorly understood with respect to its behaviour under boundary conditions different from today. For last glacial conditions, model simulations and rare proxy records of interannual climate variability in the Pacific are contradictory. Here we present a monthly resolved reconstruction of tropical South Pacific climate from 15,000 years ago at the end of the last glacial. This period was characterised by substantial cooling in the North Atlantic Ocean and a reduction in the strength of the Atlantic Meridional Overturning Circulation (AMOC) in response to massive iceberg discharge associated with Heinrich stadial 1 (H1). Our Sr/Ca palaeotemperature record constructed from a fossil coral recovered by Integrated Ocean Drilling Program (IODP) Expedition 310 to Tahiti indicates pronounced interannual ENSO variability, even though the site is only weakly influenced by ENSO today. From our coral record and simulations with a comprehensive climate model (CCSM3) we conclude that interannual ENSO variability in the tropical Pacific was strong during H1. Our results suggest that enhanced interannual variability in tropical Pacific temperatures is the ENSO response to a reduced AMOC under glacial boundary conditions.