大気圏の遮断と,大西洋の数十年にわたる海洋の変動
Sirpa Häkkinen1, Peter B Rhines, Denise L Worthen
1National Aeronautics and Space Administration (NASA) Goddard Space Flight Center, Code 615, Greenbelt, MD 20771, USA. sirpa.hakkinen@nasa.gov
まとめ
北大西洋における大気阻害現象は,海洋循環に影響を与え,温暖で塩分が高い亜極海の形成につながります. この関連は,過去の温暖化傾向を含む,長期の海洋変動を説明する.
科学分野:
- 気候学と海洋学
- 大気科学 大気科学
- 海洋-大気相互作用
背景:
- 大気遮断は,大気圏の広い地域を,長期間 (≥5日) にわたって風力から隔離します.
- これらのブロックイベントは,北大西洋の風のパターンに大きく影響し,その結果,海洋の循環と性質に影響します.
研究 の 目的:
- 北大西洋における大気遮断と海洋循環と特性の関係を調査する.
- 大気圏の遮断が観測された海洋温暖化と塩分パターンの説明であるかどうかを決定し,その中には10年単位および複数十年単位での変動性が含まれています.
主な方法:
- 北大西洋北部の大気遮断周波数と位置の分析.
- ブロックイベントと海洋学的データとの相関関係,亜極海の温度と塩分度に焦点を当てた.
- 遮断されたシステムに関連した風力強制の検討と,海洋の回転と熱交換への影響.
主要な成果:
- グリーンランドと西欧の間の頻繁な大気遮断クラスターは,より暖かく,より塩分のある亜極海条件に対応します.
- この相関は,最近の10年期 (例えば,1996-2010年) とより長い時間スケールで明らかです.
- 遮断された状態から強風が押し寄せてくるので,海洋の回転と熱交換が弱まり,大西洋多年周期変動 (AMV) の温暖化期に寄与する.
結論:
- 大気阻害は北大西洋の変動の主要な要因であり,短期的および長期的気候パターンの両方に影響を与えます.
- この研究は,遮断された風と暖かい海洋状態の間の関連性を確認し,20世紀半ばの温室効果ガスの温暖化以前の現象のような現象を説明しています.
- これらの海洋と大気間の相互作用を理解することは,将来の気候変動と海洋の行動を予測するために極めて重要です.
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