地下水中の貴重ガスから古気温を再構築し,閉じ込められた空気との均衡を考慮する
Aeschbach-Hertig1, Peeters, Beyerle
1Department of Water Resources and Drinking Water, Swiss Federal Institute of Environmental Science and Technology (EAWAG), Dubendorf, Switzerland. aeschbach@eawag.ch
Nature
|July 13, 2000
まとめ
地下水中の高貴なガスは,過去の気温を推定することができますが,
科学分野:
- 地質化学 地質化学
- 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
- 水文地質学 水文地質学は,水文地質学である.
背景:
- 地下水の貴気ガス濃度は,過去の気温のプロキシとして使用されます.
- 温度に依存しない成分である"余分な空気"の存在は,精度を制限します.
- 余分な空気の起源と構成は依然として十分に理解されていないため,過去の気候再構築に疑問を投げかけています.
研究 の 目的:
- 地下水に溶けたガスの新しいモデルを提案する.
- 捕まえた土壌空気との地下水の均衡による余分な空気の形成を説明するために.
- 過去の温度を再構築するために貴重ガスの使用を再評価する.
主な方法:
- 地下水に溶けたガスのモデルを開発した.
- このモデルは,準飽和土壌における空気の捕らわれ方による地下水の均衡による余分な空気形成を記述しています.
- このモデルを,これまで説明されていない貴重ガスデータセットとヘリウム同位体データに適用した.
主要な成果:
- このモデルは,大気中のヘリウムを含む貴重ガス濃度をうまく予測しています.
- これは,地下水の年代測定に使用される大気圏外のヘリウム同位体に対して一貫した結果を提供します.
- ノーブルガスを用いた過去の気温の再構築は再評価される.
結論:
- 提案されたモデルは,余分な空気の形成と影響を明確にします.
- この研究は,最後の氷河期最大期の間,熱帯アメリカにおける著しい冷却を裏付けている.
- 証拠によると,同じ期間に中緯度でさらに大きな冷却が起こったことが示唆されています.
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