崩壊前のグラウンドラインの境界条件,ラッセンB氷棚,南極
まとめ
2002年のラーセン-B氷棚の崩壊は,地表の温暖化によるものであって,接地ゾーンの不安定性によるものではなかった. これは,表面プロセスが氷棚の崩壊を制御し,氷の流れ規制に影響を及ぼすことを示唆しています.
科学分野:
- 氷河学 氷河学とは
- 海洋地質学 海洋地質学
- 気候科学 気候科学
背景:
- 接地ゾーンは,岩床と浮遊氷をつなぎ,氷床の流れを調節する.
- 2002年のラーセン-B氷棚の崩壊により,クレーンフィヨルドの海底が研究のために露出しました.
- 接地ゾーンのダイナミクスを理解することは,氷床の振る舞いを予測するために非常に重要です.
研究 の 目的:
- ラルセン-B氷棚の崩壊後のクレーン・フィヨルドの接地ゾーンの堆積物システムを調査するために.
- 2002年のLarsen-B氷棚の崩壊に影響を与えた要因を決定する.
- 接地ゾーンの不安定性と表面温暖化の役割を評価する.
主な方法:
- 海底の地図を作成するために2006年に海洋地質学的調査を行いました.
- モルフォロジックマッピングと沈殿体コアサンプリング.
- 沈殿体核の放射性炭素年代測定により,年代順を決定する.
主要な成果:
- クレーン・フィヨルドの氷のフロントで,複雑な弧状の接地ゾーンの堆積物系が特定されました.
- 堆積物コアのデータは,約12,000年前に床から氷の消失を示しています.
- クレーン氷河の接地ゾーンは,2002年の氷棚崩壊後までフィヨルド内で安定したままでした.
結論:
- 2002年のラーセン-B氷棚の崩壊は,主に地表温暖化への反応でした.
- 接地ゾーンの不安定性は,氷床の崩壊の主な要因ではなかった.
- 表面プロセスが,ラーセン氷床の安定性と崩壊を制御する支配的な要因であるようです.
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