1990年代,北大西洋亜極循環の減少
Sirpa Häkkinen1, Peter B Rhines
1NASA Goddard Space Flight Center, Code 971, Greenbelt, MD 20771, USA. sirpa.hakkinen@nasa.gov
Science (New York, N.Y.)
|April 17, 2004
まとめ
北大西洋における海面の高さの変化は,1990年代に亜極回転循環が弱まっていることを示している. この傾向は,表面浮力強制によって引き起こされ,水柱の奥深くまで広がり,海洋のダイナミクスに影響を与えました.
科学分野:
- 海洋学 海洋学 海洋学
- 気候科学 気候科学
- 地質物理学 地質物理学とは地質物理学です.
背景:
- 北大西洋は,海面の高さ (SSH) の大きな変動を経験しています.
- 海洋循環パターンは,世界の気候規制にとって極めて重要です.
研究 の 目的:
- 北大西洋の海面の高さの変化と,過去10年にわたる亜極回転の循環を分析する.
- 表面強制と海洋循環のダイナミクスとの関係を調査する.
主な方法:
- TOPEX/ポセイドン衛星の高度計データを活用して,地質速度を導き,SSHを分析した.
- 過去の衛星データを統合して,数十年にわたる流通動向を比較する.
- ラブラドール海からの直流メーター観測と水文データを使用した.
- 地元の表面浮力を分析し,その動的効果を理解することを強制した.
主要な成果:
- 1990年代には亜極性SSHの増加が観察され,亜極性ジアの循環が弱まっていることを示した.
- 証拠によると,1990年代の亜極循環は,1970年代と1980年代よりも弱かった.
- 電流計と水文学的データは,1990年代半ばから後半にかけて,深水柱の循環が減少したことを確認しています.
- 1990年代の弱まった熱ハリン強制は,亜極性同極性構造と循環の崩壊と関連していた.
結論:
- 北大西洋の亜極回転循環は1990年代に著しく弱まった.
- 表面浮力強制は,これらの観察された循環変化を誘導する上で重要な役割を果たしました.
- これらの発見は,海洋循環が気候強制に敏感であることを強調しています.
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