グリーンランドの氷床の消去地帯で,溶融によって引き起こされた大規模で急速な速度の変化
R S W van de Wal1, W Boot, M R van den Broeke
1Institute for Marine and Atmospheric research Utrecht, Utrecht University, Netherlands. r.s.w.vandewal@uu.nl
Science (New York, N.Y.)
|July 5, 2008
まとめ
グリーンランドの氷の速度は,融水によって劇的に増加しますが,システム調整により,全体的な氷の流れは安定しています. この季節的なフィードバックは,氷床への長期的な気候変動の影響を制限する可能性があります.
科学分野:
- 氷河学 氷河学とは
- 気候科学 気候科学
- 地球観測 地球観測
背景:
- グリーンランドの氷床が気候変動に与える影響は,重要な研究分野です.
- 氷のダイナミクス,特に速度の変化を理解することは,海面上昇を予測する鍵です.
研究 の 目的:
- グリーンランドの氷床の消去地帯における氷の速度の急速な変動を調査するために.
- 融水生成と氷の速度との関係を定量化するために.
- 氷床の安定性に対するこれらの動態の長期的な影響を評価する.
主な方法:
- 継続的なグローバルポジショニングシステム (GPS) の観測が利用されました.
- 分析は,グリーンランド氷床の西側アブレーションゾーンに焦点を当てた.
- データには短期 (日) と長期 (17年) の期間が含まれる.
主要な成果:
- 氷の速度は,溶けた水の増加に反応して数日以内に4倍に増加した.
- この迅速な対応は,以前に記録されたものよりもはるかに強力で迅速です.
- 短期的な変動にもかかわらず,年間氷の速度は17年間でわずかに減少し,システムの調整を示しています.
- 融解率と氷の速度との間の季節的なポジティブフィードバックメカニズムが特定されました.
結論:
- 氷床の水力システムは,溶融水量の変動に常に調整され,比較的安定した氷の流れを維持しています.
- 確認されたフィードバックメカニズムは,主に季節的であり,長期の温暖化に対する氷床の反応に限られた影響を与える可能性がある.
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