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-P09] Bipolar-seesaw oscillations and deglaciation with MIROC AOGCM

*Ayako Abe-Ouchi1,2,3, Sam Sherriff-Tadano1, Takashi Obase1, Wing-Le Chan1, Akira Oka1, Masakazu Yoshimori4, Kenji Kawamura3 (1.Atmosphere and Ocean Research Institute, The University of Tokyo, 2.JAMSTEC, 3.NIPR, 4.Hokkaido University)

Keywords:climate model, deglaciation, ice sheet

During the last termination of ice age cycle (deglaciation), Heinrich event 1 as well as B/A, Antarctic Cold Reversal (ACR) and Younger Dryas occurred as millennial scale climate changes. Here we ran several deglaciation experiments as well as sensitivity experiments using a coupled atmosphere and ocean GCM (MIROC4m AOGCM) developed in Japan and analyzed the stability of AMOC and climate. The model was also run for 10000 years under many different conditions with constant Greenhouse Gas levels with glacial ice sheet and with and without freshwater flux into North Atlantic region. The results show large oscillation of AMOC and high latitude temperature change similar to B/A and D-O cycles, comparable with ice core data and deep-sea data for some cases. We show that the D-O like oscillation and B/A type change occur under limited range of CO2 and freshwater forcing. The conventional hysteresis curve of stability diagram of AMOC is also analyzed by changing gradually the freshwater flux in the North Atlantic. Implication on the mechanism of the millennial scale climate changes is discussed.