北大西洋の北部の水分は,ここ数十年にわたって稀化した
Ruth Curry1, Cecilie Mauritzen
1Woods Hole Oceanographic Institution (WHOI), Woods Hole, MA 02543, USA. rcurry@whoi.edu
Science (New York, N.Y.)
|June 18, 2005
まとめ
1960年代から北大西洋に大量の淡水が加えられ,重要な地域が新鮮化しています. この重要な淡水流入は,次世紀中に大西洋南極の転覆循環に影響を与える可能性があります.
科学分野:
- 海洋学 海洋学 海洋学
- 気候科学 気候科学
- 水文学 水文学とは,水文学の学問である.
背景:
- 海洋の塩分度は,淡水の流れの重要な指標である.
- 北大西洋は,世界の海洋循環パターンにおいて重要な役割を果たしています.
研究 の 目的:
- 北欧海と亜極域の盆地に流入する淡水の量とタイミングを定量化するために.
- 観測されたフレッシングが,大西洋南極の転覆循環に与える潜在的な影響を評価する.
主な方法:
- 1960年代半ばから1990年代半ばまでの歴史的な塩分データの分析.
- 塩分変化に基づく淡水量と入水率の推定.
主要な成果:
- 推定19,000 +/- 5000立方キロメートルの余分な淡水が1965年から1995年の間に北欧海と亜極域盆地に流入した.
- この淡水の約1万立方キロメートルは,1960年代後半に年間2000立方キロメートルの速度で流入した.
- 観測された淡水蓄積は,重要な新鮮化の値に到達するために,百年もの長い時間スケールを示唆しています.
結論:
- 20世紀半ば以来,北大西洋の北部では,著しい新鮮化が起こっています.
- 特に1960年代後半の淡水投入の割合は相当なものでした.
- これらの変化は,大西洋南極の転覆循環の安定性に対して長期的な影響を及ぼす可能性があります.
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