日本地球惑星科学連合2018年大会

講演情報

[EJ] Eveningポスター発表

セッション記号 M (領域外・複数領域) » M-IS ジョイント

[M-IS06] 南大洋・南極氷床が駆動する全球気候変動

2018年5月21日(月) 17:15 〜 18:30 ポスター会場 (幕張メッセ国際展示場 7ホール)

コンビーナ:関 宰(北海道大学低温科学研究所)、岡 顕(東京大学大気海洋研究所)、真壁 竜介(国立極地研究所、共同)、植村 立(琉球大学 理学部)

[MIS06-P01] Argoが捉えたオーストラリア-南極海盆における亜寒帯循環の構造

*山崎 開平1,2青木 茂1小林 大洋3嶋田 啓資4北出 裕二郎4 (1.北海道大学 低温科学研究所、2.北海道大学 環境科学院、3.国立研究開発法人海洋研究開発機構、4.東京海洋大学)

キーワード:南大洋、Argoフロート、海洋物理学

Revealing a physics of the Antarctic subpolar gyre is substantial to understand the exchange processes of heat and materials in the Antarctic continental margin. Here we show autonomous profiling float (Argo) data over the past decade revealed the structure of the circulation in the seasonal ice zone off East Antarctica. A new method is introduced to utilize Argo under ice whose position is not well-determined. We devised automated position interpolation algorithm so as to follow isobaths, which is consistent with the contour of ambient potential vorticity. Estimation error by this interpolation was evaluated using the data whose coordinate are well-determined. The new scheme recovered as much as 40% of profiles in the seasonal ice zone. Their trajectories at 1000dbar clarified the horizontal velocity field of the continental margin(see Figure 1). The subpolar gyres off Wilkes Land and possibly off Mac Robertson Land (Prydz Bay Gyre) seem to be bounded by the westward ASF to the south and the eastward velocity maximum along 62-64S to the north in the Australian-Antarctic Basin. The eastward velocity maximum along 60-62S very likely corresponds to the southern ACC front (Kim and Orsi, 2014). The velocity maximum along 62-64S probably corresponds to the climatological position of Southern Boundary of ACC (or SB, based on Orsi et al. 1995; red curve in Figure 1), although the latitude is found systematically to the north of SB. Additionally, CTD data provided by Argo inferred a characteristic structure of isopycnals. The result provides a detailed structure of subpolar gyres broadly consistent with Wakatsuchi et al., 1994, indicating a strong control of coastal bathymetry.