Asynchrony between Antarctic temperature and CO$_2$ associated with obliquity over the past 720,000 years

• Published in: Nature Communications
• Main Authors: Uemura, Ryu, Motoyama, Hideaki, Masson-Delmotte, Valérie, Jouzel, Jean, Kawamura, Kenji, Goto-Azuma, Kumiko, Fujita, Shuji, Kuramoto, Takayuki, Hirabayashi, Motohiro, Miyake, Takayuki, Ohno, Hiroshi, Fujita, Koji, Abe-Ouchi, Ayako, Iizuka, Yoshinori, Horikawa, Shinichiro, Igarashi, Makoto, Suzuki, Keisuke, Suzuki, Toshitaka, Fujii, Yoshiyuki
• Other Authors: University of the Ryukyus Okinawa, National Institute of Polar Research Tokyo (NiPR), 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), Glaces et Continents, Climats et Isotopes Stables (GLACCIOS), 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)), Graduate University for Advanced Studies Hayama (SOKENDAI), Graduate School of Engineering, Kyoto University, Katsura, Nishikyo-ku, Kyoto 615-8510, Japan, Center for Climate System Research Kashiwa (CCSR), The University of Tokyo (UTokyo), Institute of Low Temperature Science Sapporo, Hokkaido University Sapporo, Japan, Shinshu University Nagano, Graduate School of Science and Engineering Yamagata, Yamagata University, ANR-07-BLAN-0125,DOME A,Dome A : Observation et Modélisation d'un Environnement extrême en Antarctique(2007), ANR-14-CE01-0001,ASUMA,Amélioration de la précision de l'estimation de bilan de masse de surface en Antarctique(2014)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2018
• Subjects: [SDE]Environmental Sciences; [SDE.MCG]Environmental Sciences/Global Changes; Antarctic; Southern Ocean; The Antarctic; Antarc*; ice core
• Online Access: https://cea.hal.science/cea-01875223; https://cea.hal.science/cea-01875223/document; https://cea.hal.science/cea-01875223/file/s41467-018-03328-3.pdf; https://doi.org/10.1038/s41467-018-03328-3

International audience The δD temperature proxy in Antarctic ice cores varies in parallel with CO$_2$ through glacial cycles. However, these variables display a puzzling asynchrony. Well-dated records of Southern Ocean temperature will provide crucial information because the Southern Ocean is likely key in regulating CO$_2$ variations. Here, we perform multiple isotopic analyses on an Antarctic ice core and estimate temperature variations at this site and in the oceanic moisture source over the past 720,000 years, which extend the longest records by 300,000 years. Antarctic temperature is affected by large variations in local insolation that are induced by obliquity. At the obliquity periodicity, the Antarctic and ocean temperatures lag annual mean insolation. Further, the magnitude of the phase lag is minimal during low eccentricity periods, suggesting that secular changes in the global carbon cycle and the ocean circulation modulate the phase relationship among temperatures, CO$_2$ and insolation in the obliquity frequency band.