Japan Geoscience Union Meeting 2022

Presentation information

[J] Oral

M (Multidisciplinary and Interdisciplinary) » M-IS Intersection

[M-IS18] Paleoclimatology and paleoceanography

Thu. May 26, 2022 3:30 PM - 5:00 PM 304 (International Conference Hall, Makuhari Messe)

convener:Hitoshi Hasegawa(Faculty of Science and Technology, Kochi University), convener:Yusuke Okazaki(Department of Earth and Planetary Sciences, Graduate School of Science, Kyushu University), Akitomo Yamamoto(Japan Agency for Marine-Earth Science and TechnologyAtmosphere and Ocean Research Institute), convener:Atsuko Yamazaki(Faculty of Science, Kyushu University), Chairperson:Akitomo Yamamoto(Japan Agency for Marine-Earth Science and TechnologyAtmosphere and Ocean Research Institute)

4:15 PM - 4:30 PM

[MIS18-08] Effect of Climatic Precession on Dansgaard-Oeschger-like oscillations

*Yuta Kuniyoshi1, Ayako Abe-Ouchi1, Sam Sherriff-Tadano1, Wing-Le Chan1, Fuyuki SAITO2 (1.The University of Tokyo, 2.JAMSTEC)


Keywords:paleoclimate, climate variability, AMOC, sea-ice, AOGCM, glacial period

Using the climate model MIROC4m, we simulate self-sustained oscillations of millennial-scale periodicity in the climate and Atlantic meridional overturning circulation under glacial conditions. We show two cases of extreme climatic precession and examine the mechanism of these oscillations. When the climatic precession corresponds to strong (weak) boreal seasonality, the period of the oscillation is about 1,500 (3,000) years. During the stadial, hot (cool) summer conditions in the Northern Hemisphere contribute to thin (thick) sea ice, which covers the deep convection sites, triggering early (late) abrupt climate change. During the interstadial, as sea ice is thin (thick), cold deep-water forms and cools the subsurface quickly (slowly), which influences the stratification of the North Atlantic Ocean. We show that the oscillations are explained by the internal feedbacks of the atmosphere-sea ice-ocean system, especially subsurface ocean temperature change and salt advection feedback with a positive feedback between the subpolar gyre and deep convection.