湾岸流の密度構造と過去千年における輸送
David C Lund1, Jean Lynch-Stieglitz, William B Curry
1Massachusetts Institute of Technology/Woods Hole Oceanographic Institution Joint Program in Oceanography, Woods Hole, Massachusetts 02543, USA. dlund@gps.caltech.edu
Nature
|December 1, 2006
まとめ
小さな氷河期の間,湾岸流は弱まり,北大西洋の冷却に潜在的に貢献しました. この研究では,過去の海洋条件と気候を再構築するために堆積物核を使用しました.
科学分野:
- 海洋学 海洋学とは
- 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,古代気候学 (paleoclimatology) とは,古代気候学 (paleoclimatology) とは
- 気候科学 気候科学
背景:
- 湾岸流は,熱と水を北大西洋に運ぶ主要な海流です.
- 長期にわたる湾岸流の変動を理解することは,気候変動の予測に不可欠です.
- 楽器の記録は,何世紀にもわたる気候の変動を捉えるには短すぎる.
研究 の 目的:
- 地質学的アーカイブを使用して,過去の湾流の行動を再構築する.
- 小さな氷河期のような過去の気候現象における湾岸流の役割を調査する.
- 大西洋の循環と水循環の関連性を評価する.
主な方法:
- フロリダ海峡の高解像度堆積物コアからのフォラミニフェラの分析.
- 交差電流密度グラデーションと垂直電流切断の再構築.
- 過去の輸送量と表面塩分量の推定.
主要な成果:
- 湾岸流は,小氷河期 (大約1800年) の間,系統的に低い交流密度グラデーションと垂直流切断を示した. 紀元前1200年~1850年).
- 推定小氷河期の輸送量は,現在の値より約10%弱かった.
- 流量の減少は,気温の最小値と異常な高表面塩分と一致し,水循環とのつながりを示した.
結論:
- 湾岸流による海洋熱伝達の減少は,北大西洋の小さな氷河期の冷却に寄与した可能性がある.
- この研究は,大西洋の循環と過去千年の水循環との密接な関連性を強調しています.
- パレオセアノグラフィのデータは,長期的な気候動態と海洋の現在の行動に関する重要な洞察を提供します.
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