[A-CC21] アイスコアと古環境変動

[ACC21-07] 氷期中のミレニアムスケールの急激な気候変動のMIROC大気海洋結合モデルによる再現

*阿部 彩子^1,2,3、陳 永利¹、大垣内 るみ²、川村 賢二³、吉森 正和⁴、岡 顕¹、シェリフ多田野 サム¹ (1.東京大学大気海洋研究所、2.海洋研究開発機構、3.国立極地研究所、4.北海道大学)

キーワード：古気候、気候モデル

Millennial climate change such as D-O cycles and AIM recorded in ice cores in both Hemispheres is knownto show a relatively higher amplitude in the middle-level of a glacial cycle than in the interglacial state or severeglacial state. Here we ran several sensitivity experiments using a coupled atmosphere and ocean GCM (MIROC4m,renamed from MIROC3.2.2) and show that the response to fresh water release to the ocean and bipolar responseis highly dependent on the background climate. The experiments were conducted with 500 years water hosingof 0.05 to 0.1 Sv (where 1 Sv is equivalent to the water flux of 10m sea level rise in 100 years) in the NorthAtlantic 50-70N under different basic states; modern climate state with the pre-industrial condition, middle glacialclimate state and full glacial condition, mainly differing in the ice sheet configuration and atmospheric amount ofGreenhouse Gases. The results under middle glacial condition show largest cooling/warming response in NorthAtlantic and a reasonable bipolar warming/cooling signal revealed in the ice core data of the both hemisphere. Wediscuss the responses under different background climates which involve the strong coupling between atmosphere,ocean and sea ice and their dependence on the configuration of ice sheet.