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A Rapid Method for Modeling a Variable Cycle Engine
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北緯25度における大西洋南極転覆循環の減速
Harry L Bryden1, Hannah R Longworth, Stuart A Cunningham
1National Oceanography Centre, Empress Dock, Southampton SO14 3ZH, UK. h.bryden@noc.soton.ac.uk
Nature
|December 2, 2005
まとめ
大西洋南極の転覆循環は1957年以来30%減速している. この著しい減速は熱伝送に影響を与え,気候変動と欧州の気象パターンに影響を及ぼします.
科学分野:
- 海洋学 海洋学 海洋学
- 気候科学 気候科学
- 地球システム科学 地球システム科学
背景:
- 大西洋南極反転循環 (AMOC) は,地球温暖化分布にとって極めて重要です.
- AMOCの熱伝達は,欧州の気候を大幅に緩和する.
- AMOCの変化は,気候変動に重大な影響を及ぼします.
研究 の 目的:
- 大西洋南極逆転循環 (AMOC) の変化を評価する.
- AMOCの熱伝送の変化を5十年で定量化するために.
- AMOCの減速の原因を分析する.
主な方法:
- 北緯25度にある新しい大西洋横断海洋学断面の分析.
- 1957年から2004年までの4つの歴史的なトランスアトランティックセクションとの比較.
- 様々な深さでの水質輸送の定量化.
主要な成果:
- 大西洋南極転覆循環 (AMOC) は,1957年から2004年の間に約30%減速した.
- 湾岸流による北向きの熱輸送は,北緯25度で比較的一定であった.
- 熱クラインの水の南向き再循環の増加と深水の南向き輸送の減少が観察されました.
結論:
- 観測されたAMOCの減速は,亜熱帯圏内の循環パターンの変化に起因する.
- 浅い水が南へ戻っており,循環の深部が弱まっていることを示している.
- これらの変化は,将来の気候予測に重大な影響を及ぼします.
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