床の摩擦は,氷河の急速な流れを制御しない

L A Stearns^1,2, C J van der Veen³

¹Department of Geology, University of Kansas, Lawrence, KS 66045, USA. stearns@ku.edu.

Science (New York, N.Y.)

|June 9, 2018

まとめ

現在の氷床モデルでは海面上昇を正確に予測できないのは氷河の基礎滑動を誤って解釈しているからです新しい分析により滑り速度は摩擦力ではなく氷床の表面圧力の関係にあることが分かりました

科学分野:

氷河学
気候科学
地球システム科学

背景:

海面上昇の予測には氷床モデルが不可欠です
氷床との接点の基礎滑動は氷の流れを制御する重要な要因です
現在のモデルでは,ハードベッドから派生した時代遅れのスライディングパラメータを使用しています.

研究の目的:

氷床モデルで使用されている現在の基礎滑りパラメータの有効性を調査する.
グリーンランドの氷河の氷床界面における基礎滑りとストレスとの関係を分析する.
発見を既存の理論と山の氷河の観測と比較する.

主な方法:

グリーンランドの140の氷河からの基礎滑りデータを分析した.
スライド速度と摩擦の緊張の関係に関する研究.
氷河床での滑り速度と純圧の相関を調査する.

主要な成果:

硬層の理論的滑り関係は,分析されたグリーンランドの氷河には適用されません.
基礎滑りと摩擦のストレスとの間に有意な関係が見つかりませんでした.
氷河床の滑り速度と圧力の強い相関関係がある.

結論:

既存の氷床モデルでは基礎滑走の仮定が誤っているため将来の海面上昇を過大評価したり過小評価したりすることがあります
滑動速度と純圧の関係は,基礎滑動のより正確なパラメータ化を提供します.
海面上昇の予測を改善するために,基礎過程に関するさらなる研究が不可欠です.

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