熱ハリン循環における短路:北半球氷河化の原因?
1N. W. Driscoll, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA. G. H. Haug, GEOMAR, Forschungszentrum fur Marine Geowissenschaften, Universitat Kiel, Wischhofstrasse 1-3, D-24148 Kiel, Germany.
まとめ
北半球の氷河化の原因は不明である. 北極へのシベリア川の淡水供給の強化は,アルベドを増加させ,海洋の熱伝搬を減少させることで氷の形成を促進した可能性がある.
科学分野:
- 地球科学 地球科学 地球科学
- 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
背景:
- プレオセーン-プレイストセーン移行期 (約300万年前) は北半球氷河期の始まりであり,主要な気候変化をもたらしました.
- パナマ領峡の閉鎖は,海洋循環と高緯度の水分を向上させるが,熱輸送の増加のために氷の成長を潜在的に抑制する,提案されたドライバーである.
研究 の 目的:
- 北半球氷河化の潜在的なメカニズムを調査し,湿度と熱伝達の増加の影響を調和させる.
主な方法:
- この研究は,既存の古海洋学および気候モデルに基づいた仮説を提唱しています.
- 北極海への淡水排出の役割に焦点を当てています.
主要な成果:
- 大気循環の強化によってユーラシアへの水分輸送が強化されれば,シベリアの川を通って北極海に淡水流出が増加する可能性があります.
- この淡水流入は,海氷の形成を促進し,それによって惑星のアルベドを増加させる可能性があります.
- 海氷の覆いが増加すると,海が隔離され,大気への熱伝達は減り,温暖化効果は和らげる.
結論:
- シベリアの川を経由して北極に淡水の供給は,北半球の氷河化を開始するための合理的なメカニズムを提供します.
- このプロセスは,氷の覆いが増加すると,海洋と大気間の熱交換が減少し,さらに冷却と氷の成長を促進する負のフィードバックループを伴う.
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