古代気候学:海洋同位体ステージ11の記録
Dominique Raynaud1, Jean-Marc Barnola, Roland Souchez
1Laboratoire de Glaciologie et Géophysique de l'Environnement, CNRS, 38402 Saint-Martin-d'Hères, France. raynaud@lgge.obs.ujf-grenoble.fr
Nature
|July 8, 2005
まとめ
海洋同位体ステージ11 (MIS11) は,例外的に長い氷河期間の期間であり,大気中の二酸化炭素レベルは工業化以前の時代と同等であった. 太陽エネルギーとCO2の両方が,その延長期間に貢献した可能性が高い.
科学分野:
- 古代気候学 (paleoclimatology) とは,古代気候学 (paleoclimatology) とは,古代気候学 (paleoclimatology) とは,古代気候学 (paleoclimatology) とは,古代気候学 (paleoclimatology) とは
- 地球科学 地球科学 地球科学
- 気候史 気候史
背景:
- MIS11 (Marine Isotopic Stage 11) は,約40万年前,異常に長い氷河期間の期間でした.
- MIS 11の軌道気候フォースは,現在の氷河期間の条件に似たような,弱い太陽エネルギー分布の変化を示した.
研究 の 目的:
- MIS 11 の大気中の二酸化炭素記録を再構築する.
- MIS 11の例外的な長さに寄与する要因を調査する.
- MIS 11の気候ダイナミクスを現在の氷期間の条件と比較する.
主な方法:
- Antarctic Vostokのコアからの氷のコアデータを活用しました.
- MIS 11 の完全な大気中の二酸化炭素記録を再構築しました.
- 海洋炭酸塩系における海洋沈殿物の異常を分析した.
主要な成果:
- MIS 11における大気中の二酸化炭素レベルは,工業化以前のレベルに近い水準であった.
- 太陽光エネルギー分布と二酸化炭素濃度の両方が,MIS 11の延長期間に貢献したようです.
- 海洋炭酸塩系異常は,この期間に大気中のCO2に重大な影響を及ぼさなかった.
結論:
- MIS 11の長さは,安定した太陽エネルギーと適度な大気中のCO2の組み合わせによって影響を受けた可能性が高い.
- この発見は,氷期間の気候の安定性と,現代の気候の動態との潜在的な類似性についての洞察を提供します.
- 過去の氷河期間の大気中のCO2レベルは,これまで考えられていたよりも,海洋の変化に対してより強固であったかもしれない.
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