[A-CC26] Ice cores and paleoenvironmental modeling

[ACC26-06] Comparative analysis of interglacial (MIS1, 5e, 11) climate responses to orbital elements and internal feedbacks

*Lynn Hirose¹, Ayako Abe-Ouchi¹, Wing-Le Chan¹ (1.the University of Tokyo)

Keywords:interglacial, internal feedback, North American Ice Sheet

It is generally believed that the glacial ice volume variations that define the glacial-interglacial cycle are driven by changes in summer insolation at Northern hemisphere high latitudes due to periodic changes in the Earth's orbital elements. However, MIS11, which is known to be one of the warmest interglacials with the highest sea levels, cannot be easily explained by orbital elements and greenhouse gases (GHGs) alone, pointing to the need to consider amplifying feedbacks and broader-scale effects. In this study, we compare the climate simulations of MIS11 with that of MIS1 and MIS5e using a coupled atmosphere-ocean vegetation model (MIROC 4m AOVGCM), focusing on the presence or absence of ice sheets in order to examine the effects of different internal feedbacks on temperature in the Northern Hemisphere high latitudes. The orbital elements, land cover, including ice sheet distribution, and GHGs were fixed every 5000 years as boundary conditions and the experiments were run for more than 3000 years each with appropriate initial conditions. The preliminary results of surface air temperature, sea ice distribution, and albedo at Northern Hemisphere high latitudes and the role of the North American Ice Sheet as well as vegetation change will be discussed.