グリーンランドの氷床の融解による加速は,効率的な氷床下排水によって相殺されます
Aud Venke Sundal1, Andrew Shepherd, Peter Nienow
1School of Earth and Environment, University of Leeds, Woodhouse Lane, Leeds, LS2 9JT, UK.
Nature
|January 29, 2011
まとめ
表面の融解はグリーンランドの氷床の流れに影響します. 温暖な年は,基底潤滑だけでなく,効率的な排水により,気候変化モデルに影響を与える夏の氷の流れが遅くなります.
科学分野:
- 氷河学 氷河学とは
- 気候科学 気候科学
- 地球システム科学 地球システム科学
背景:
- 表面の融解は,氷河と氷床の動態に影響を与えます.
- 温暖化が進むグリーンランドの氷床の流れに対する融解の増加の影響は不確実であり,これまでの研究結果は矛盾している.
研究 の 目的:
- グリーンランドの氷床の陸端部分における氷の流れが,表面の融解が変化する年にわたってどのように変化するかを調査する.
- 融水流出と氷の速度の関係を理解するため,特に暖かい年に.
主な方法:
- グリーンランドの南西部の氷の動きの衛星観測を利用した.
- 氷の流れパターンを分析し,溶解条件が著しく異なる年に渡って氷の流れパターンを分析した.
- 排水システムのダイナミクスを組み込む氷床の流れモデルを開発し,適用しました.
主要な成果:
- 氷のピークのスピードアップは融解の強度と相関しているが,夏の平均フロー率はそうではない.
- 氷河の減速は,特に暖かい年に,毎日の流水量が約1.4cmを超えると起こります.
- 暖かい年は,夏末の加速が低下し,急速な流れの期間が短く,全体的に夏の氷の流れが,より涼しい年に比べて遅くなる.
結論:
- 温暖な年のグリーンランド氷河の流れは,単なる基礎潤滑ではなく,山の氷河と似たような効率的な氷床下流水による影響を受けます.
- 洞穴と運河の流れの間の移行を含む,亜氷河水流のダイナミックな進化は,気候温暖化への氷床の反応を正確にモデル化するために不可欠です.
- 気候変動によるグリーンランドの氷床の流れの将来のシミュレーションは,信頼性の高い予測のために,これらの排水ダイナミクスを組み込む必要があります.
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