古代の氷河における気候シグナルが,プレメルトと異常な拡散によって異動した可能性がある
A W Rempel1, E D Waddington, J S Wettlaufer
1Applied Physics Laboratory, University of Washington, Box 355640, Seattle, Washington 98105, USA. awrempel@apl.washington.edu
Nature
|June 1, 2001
まとめ
氷のコアでのプレメルトは,不純の異常がより暖かい地域へ移動することを引き起こします. この堆積後の移動は,気候信号を最大50cmまで分離し,古気候の再構築に影響を与える可能性があります.
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
- 氷河学 氷河学とは
- マテリアルサイエンス 材料科学
背景:
- 氷の芯は,数千年に及ぶ高解像度の気候記録を提供します.
- これらの記録の解釈は,微量成分の最小限の堆積後の移動を前提としています.
- 冷凍されていない穀物境界液に含まれる溶解性不純物は,重要な気候プロキシです.
研究 の 目的:
- 氷の組成の拡散に対するプレメルトングの影響を調査する.
- プレメルトングが不純物質の異常を空間的に大きく分離させることができるかどうかを判断する.
- この現象が,特にエエム期間の氷河期間の古気候再構築に与える影響を評価する.
主な方法:
- ポリ結晶氷の相行動,特にプレメルトングを調査した.
- プレメルトによる影響を受けた構成拡散をモデル化.
- グリーンランドのエミアン氷河間の氷に似た条件下で,不純物輸送のシミュレーション.
主要な成果:
- プレメルトングは,不純物質の異常がより暖かい地域へ移動することを促します.
- このプロセスは,輸送中の不純物異常の空間的整合性を維持します.
- エイミアンのような条件下では,不純物の変動は,同じ年齢の氷から50cmまで移動することができます.
結論:
- 融解前誘発の組成的拡散は,氷の核のプロキシ解釈に大きく影響する.
- 不純物の空間的分離は,氷の核内の気候信号の直接的な年代測定に挑戦しています.
- このメカニズムは,Eemian冷却イベントに関するものなど,古気候記録の不一致を説明する可能性があります.
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