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赤道水域における内部波の破裂による混合の減少
Michael C Gregg1, Thomas B Sanford, David P Winkel
1Applied Physics Laboratory, College of Fishery and Ocean Sciences, University of Washington, Seattle, Washington 98105, USA. gregg@apl.washington.edu
Nature
|April 4, 2003
まとめ
海洋の混合は,赤道付近では効率が悪くなります. 内部波の分散率と,その結果生じる交差密度の混合は,中緯度と比較して赤道地域では著しく低い.
科学分野:
- 海洋学 海洋学 海洋学
- 流体力学 流体力学
- 気候科学 気候科学
背景:
- 海洋の熱,塩,栄養素の輸送は,主として均一密度の水質の中で起こります.
- 密度の高い表面の混合は,地球の気候と生物の分布にとって極めて重要です.
- 内部波折は,密度面の渦巻混合の主要な要因である.
研究 の 目的:
- 内部波の分散と混合の緯度依存を調査する.
- 消散速度に関する以前の中緯度調査を,赤道地域にまで拡大する.
- 太平洋と大西洋の密度面の混合を定量化するために.
主な方法:
- 太平洋と大西洋の気温と速度変動データを収集する.
- 北緯42度から南緯2度までの海域を観測する.
- 消散速度と密度面の混合を分析する.
主要な成果:
- 散布率は,理論的な予測と整合して,強い緯度依存を示している.
- 赤道付近では,同等な内部波の背景の分散率は,中緯度の10%未満である.
- 密度の高い表面の混合は,赤道水域では大幅に減少しています.
結論:
- 密度の高い表面の間の海洋の混合は,赤道付近では著しく効率的ではない.
- 減少した赤道混合は,数値的な海洋ダイナミクスモデルに組み込まれなければなりません.
- これらの発見は,気候変動のモデリングと海洋生物ジオケミカルサイクルの理解に影響を及ぼします.
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