南洋の深水形成の20世紀の減速の可能性
1Lamont-Doherty Earth Observatory of Columbia University, Palisades, NY 10964, USA. Ocean Chemistry Division, Atlantic Oceanographic and Meteorological Laboratory, National Oceanic and Atmospheric Administration, Miami, FL 33149-1026, USA.
Science (New York, N.Y.)
|November 5, 1999
まとめ
南大洋の深水産量は,過去より低いため,海洋学データにおける不一致が説明される可能性がある. これは北大西洋の深水形成とアイスラフティングのサイクルに関連している可能性があります.
科学分野:
- 海洋学 海洋学とは
- 気候科学 気候科学
- 地質化学 地質化学
背景:
- 南大洋の現在の深水産量の推定値と過去のデータには相違がある.
- 以前の研究では,過去800年間に南大洋の深海換気率が著しく高かったことが示唆されています.
研究 の 目的:
- 南洋の深水産量の相反する見積もりを調和させるため.
- 気候サイクルにおける深水の生産率の変化の潜在的な役割を調査する.
主な方法:
- 南極海の深海におけるクロロフルオロカーボン11 (CFC-11) の在庫の分析.
- CFC-11データと物理海洋学および地球化学のプロクシーの比較 (例えば,炭素14/炭素比,PO4)).
主要な成果:
- 現在のCFC-11の在庫は,約5×10^6 m^3 /sの深水生産率を示唆しています.
- この割合は,炭素14とPOのデータから得られた過去の推定値 (約15 x 10^6 m^3/s) よりも低い.
- 20世紀中に南大洋の深水生産を大幅に削減することが提案されています.
結論:
- 観測された深水産量の減少は,現在の推定値と過去の推定値の差異を説明する可能性がある.
- 北大西洋と南大洋の間の潜在的なシーソーメカニズムによる深海生産は,1500年の氷河ラフティングサイクルを駆動することができます.
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