西南極から海面上昇が加速している
R Thomas1, E Rignot, G Casassa
1EG&G Inc., NASA Goddard Space Flight Center (GSFC)/Wallops Flight Facility (WFF), Building N-159, Wallops Island, VA 23337, USA. thomas@osb.wff.nasa.gov
Science (New York, N.Y.)
|September 25, 2004
まとめ
西南極の氷河は,蓄積するよりも早く氷を失い,年間250立方キロメートルの氷を排出しています. この大きな氷の減少は,世界の海面上昇に寄与し,氷床の潜在的不安定性を示しています.
科学分野:
- 氷河学 氷河学とは
- 気候科学 気候科学
- 海洋学 海洋学 海洋学
背景:
- 最近の調査によると,西南極の氷河からアムンセン海への氷の放出が加速していることが明らかになった.
- 氷河の希薄化率は1990年代から2002-2003年の間に大幅に増加しました.
研究 の 目的:
- アムンセン海の氷河からの氷の排出量を定量化するために.
- この排水が世界の海面上昇に与える影響を評価する.
- 氷河の流れに影響を与える地質学的構造を調査する.
主な方法:
- 航空機と衛星によるレーザー高度測定調査.
- 氷河流域の流域蓄積率の分析.
- 標高計データを用いて床岩の深さの推定.
主要な成果:
- 氷河は年間約250立方キロメートルの氷を放出しています.
- 氷の排出量は蓄積量をほぼ60%上回り,純損失を示しています.
- この排水は,世界の海面上昇に年間0.2ミリメートル以上貢献しています.
- 氷河の希薄化率は,2000年代初頭に著しく増加した.
- アイスシェルフの下の床岩は,以前に推定されたより深いので,さらなる氷の流れを促進する可能性があります.
結論:
- アムンドセン海域は,蓄積を上回る氷の損失を大幅に経験しています.
- 氷河の放出の加速は,世界の海面に重大な脅威をもたらしています.
- より深い岩床は,内陸からの氷の流れを継続させ,氷床の不安定性を示唆する可能性がある.
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