パレオセアノグラフィー 古代海洋学 北半球氷河化における南極の役割
Stella C Woodard1, Yair Rosenthal2, Kenneth G Miller3
1Department of Marine and Coastal Sciences, Rutgers University, 71 Dudley Road, New Brunswick, NJ 08901, USA. woodard@marine.rutgers.edu.
まとめ
北半球の氷河期は2,730万年前から始まった. 南極の氷の増加によって引き起こされた太平洋の冷たい水域と海洋循環の変化は,この主要な気候変動の移行を容易にした.
科学分野:
- 古代気候学 (paleoclimatology) とは,古代気候学 (paleoclimatology) とは,古代気候学 (paleoclimatology) とは,古代気候学 (paleoclimatology) とは,古代気候学 (paleoclimatology) とは
- 海洋学 海洋学 海洋学
- 気候科学 気候科学
背景:
- 地球の気候は,暖かいプレオセンの状態から,約2730万年前 (Ma) に北半球の大規模な氷河期 (NHG) に変化した.
- NHG以前の北太平洋の深い水域は,北大西洋の深い水域よりもかなり冷たく新鮮でした.
研究 の 目的:
- 北半球氷河期の前およびその間における深海循環の変化を調査する.
- この大きな気候変動の移行における半球間熱と塩の輸送の役割を理解するために.
主な方法:
- 深海の温度と塩分度の古海洋学的な再構築.
- 南極氷河の範囲を推測するために,海面の変化の分析.
- 深海循環のダイナミクスのモデリング.
主要な成果:
- 北太平洋の深い水域は,NHGが激化する前に北大西洋の深い水域よりも約4°C冷たく,新鮮でした.
- 大西洋-太平洋の気温グラデーションは,約2.73万年後に<1°Cまで減少し,太平洋への熱伝達の強化を示した.
- 3.15~2.75万年前までの21±10メートルの海面低下は,南極の氷河化が増加したことを示唆している.
結論:
- 南極の氷河の増加と強い極のハロクリンは,深海の循環を根本的に変えました.
- 北半球間の熱と塩の輸送の強化は北半球氷河の発生に大きく貢献した.
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