Japan Geoscience Union Meeting 2018

Presentation information

[EJ] Evening Poster

M (Multidisciplinary and Interdisciplinary) » M-IS Intersection

[M-IS06] Global climate change driven by the Southern Ocean and the Antarctic Ice Sheet

Mon. May 21, 2018 5:15 PM - 6:30 PM Poster Hall (International Exhibition Hall7, Makuhari Messe)

convener:Osamu Seki(Institute of Low Temperature Science, Hokkaido University), Akira Oka(Atmosphere and Ocean Research Institute, The University of Tokyo), Ryosuke Makabe(国立極地研究所, 共同), Ryu Uemura(University of the Ryukyus)

[MIS06-P14] 720,000-year records of Antarctic and oceanic temperatures related to solar forcing and CO2

*Ryu Uemura1, Hideaki Motoyama2, Valerie Masson-Delmotte3, Jean Jouzel3, Kenji Kawamura2, Kumiko Goto-Azuma2, Shuji Fujita2, Takayuki KURAMOTO2,10, Motohiro Hirabayashi2, Takayuki Miyake2, Hiroshi Ohno4,2, Koji Fujita5, Ayako Abe-Ouchi6, Yoshinori Iizuka7, Shinichiro Horikawa7,5, Makoto Igarashi2, Keisuke Suzuki8, Toshitaka Suzuki9, Yoshiyuki Fujii2 (1.University of the Ryukyus, 2.National Instititute of Polar Research, 3.LSCE, CEA-CNRS, 4.Kitami Institute of Technology, 5.Nagoya University, 6.The Unviersity of Tokyo, 7.Hokkaido University, 8.Shinshu University, 9.Yamagata University, 10.Fukushima prefectual center for environmental creation)

Keywords:ice core, Antarctica, stable isotope, glacial cycle

The δD temperature proxy in Antarctic ice cores varies parallelly with CO2 through glacial cycles with a puzzling asynchrony. To understand the mechanisms responsible for this association, precise and well-dated records of Antarctic and Southern Ocean temperature are needed. Here, we performed multiple isotopic analyses on an Antarctic ice core and reconstructed the records of temperature variations at this Antarctic site and the oceanic moisture source back to 720,000 years before present, which extend the longest records by 300,000 years.We found that (1) Antarctic temperature is affected by large variations in local insolation that are induced by obliquity. At the 41-kyr obliquity periodicity, the CO2 variations display higher coherence with ocean temperature than Antarctic temperature. (2) At the obliquity periodicity band, changes in annual mean insolation were followed by changes in Antarctic temperatures, CO2, and oceanic temperatures with phase lags. (3) 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, CO2 and insolation.