大西洋南東部の氷河の表面温度
J P Sachs1, R F Anderson, S J Lehman
1Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Room E34-254, Cambridge, MA 02139, USA. jsachs@mit.edu
Science (New York, N.Y.)
|September 15, 2001
まとめ
ケープ盆地からの海洋気候記録は,最後の氷河期中に予想外の海洋温暖化を明らかにしています. 4万1千年前から2万5千年前までのこの温帯の海洋温暖化は,典型的な冷却傾向と対照的です.
科学分野:
- パレオセアノグラフィー
- 気候科学 気候科学
- 海洋地質学 海洋地質学
背景:
- 海洋沈殿物の記録は,過去の海面温度を再構築するための重要なデータを提供します.
- 最後の氷河期は,地球規模の気候変動と氷の量の変化が顕著である.
- 過去の海洋学的な変動を理解することは,将来の気候変動を予測する鍵です.
研究 の 目的:
- 最後の氷河期間の亜熱帯南大西洋の海洋気候変化を記録し,分析する.
- 海洋表面温度変動の記録されていない進行を調査する.
- 地域海洋学的変化を,地球的な気候パターンと軌道強制力と比較する.
主な方法:
- ケープ盆地における深海の沈殿体コアからの海面温度プロキシの分析.
- 堆積層の年代測定は,気候現象の正確なタイムラインを確立するために行われます.
- ケープ盆地の気温記録を,既知の古気候アーカイブと太陽照射データと比較.
主要な成果:
- ケープ盆地からの詳細な海面温度記録は,現在より41~1万8千年前を網羅しています.
- 現在より4万1千年から2万5千年前までの,気温の高い海洋温暖化の重要な間隔を特定した.
- 観測された温暖化パターンは,地球の軌道の変化による予想される太陽照射の変化と相関しています.
結論:
- ケープ盆地記録は,最後の氷河期における明確な地域的な海洋温暖化イベントを明らかにし,典型的な冷却解釈に挑戦しています.
- この温暖化段階は,地球規模の氷の量,海洋循環,軌道強制の複雑な相互作用を示唆しています.
- このこれまで文書化されていない海洋気候の進行を駆動するメカニズムを完全に理解するためには,さらなる研究が必要である.
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