夏季,上層の海層の層化と混合層の深さの増加
Jean-Baptiste Sallée1, Violaine Pellichero2,3, Camille Akhoudas4
1Sorbonne Université, CNRS/IRD/MNHN, LOCEAN, IPSL, Paris, France. jean-baptiste.sallee@locean-ipsl.upmc.fr.
Nature
|March 25, 2021
まとめ
海洋温暖化により 上層の海洋の安定性が高まり 混合層が深くなっています この研究は50年以上に渡って 世界の上層海域に 顕著な変化が起きたことを明らかにしています
科学分野:
- 海洋学
- 気候科学
- 海洋生態系
背景:
- 熱と炭素の交換を通して 地球の気候を調節するために 海洋の表面混合層は 極めて重要です
- 海の生態系を支えて 深海の層に酸素を供給します
- 気候変動による混合層の変化は十分に理解されていません.
研究 の 目的:
- 海洋の混合層の深さと安定性の変化を調査する.
- 1970年から2018年のトレンドを海洋学的な観測を用いて分析する.
- 海洋原産物と海洋のダイナミクスの影響を理解する.
主な方法:
- 1970年から2018年までの海洋観測を活用した.
- 上海の安定性に関する物理的な定義を適用した.
- 密度の対照性と,世界の海洋システムにおける混合層の深さの傾向を分析した.
主要な成果:
- 混合層の基底の密度コントラストは著しく増加した (十年あたり8.9 ± 2.7%).
- 予想に反して,混合層は深まりました (十年あたり2.9 ± 0.5%,または10年あたり5〜10m).
- 同時に層化と深化が起こると 表面の温暖化,新鮮化,そして激しい乱れが起こります
結論:
- この研究により,以前は過小評価されていた 海洋の上層部に重大な変化が 起きていることが明らかになりました
- 層分化が増加した混合層の薄めに関する以前の仮定に異議を唱えます.
- この結果は,海洋原産物と海洋生態系に影響を与える要因を再評価することを必要としています.
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