GRACEの重力データは,古代の氷の幾何学とローレンシア上の大陸の動態を制限しています
M E Tamisiea1, J X Mitrovica, J L Davis
1Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Mail Stop 42, Cambridge, MA 02143, USA. mtamisiea@cfa.harvard.edu
Science (New York, N.Y.)
|May 15, 2007
まとめ
重力回復と気候実験 (GRACE) の衛星データは,カナダの氷河の静止調整 (GIA) と氷床の構造を明らかにしています. このGIAモデルは,大陸のテクトスフィアの浮力に関する重要なデータを提供します.
科学分野:
- 地質物理学 地質物理学とは地質物理学です.
- 衛星ジオデシは,衛星によるジオデシ.
- 氷河学 氷河学とは
背景:
- 氷河の静止調整 (GIA) を理解することは,地球の重力場を解釈する上で極めて重要です.
- 以前のローレンシア氷河複合体の再構築では,決定的な証拠が欠けていた.
- 大陸のテクトスフィアに対するGIAの影響は,正確なモデリングを必要とします.
研究 の 目的:
- GRACE衛星データを用いて,カナダ上空のGIAの重力信号を分離し分析する.
- 古代ローレンシア氷の複合体の構造を決定するために.
- マントルのコンベクションと大陸のテキトスフィアの浮力性のモデルを制約するために.
主な方法:
- GRACE衛星ミッションデータから得られた空間の重力の動向の分析.
- 観測された重力場と氷河の静止調整 (GIA) モデルの比較.
- 観測された静的重力場とピークGIA率の調和.
主要な成果:
- GRACEのデータは,マントルのコンベクションからGIAの重力信号をしっかりと分離した.
- 証拠は,ハドソン湾の西と東に2つの大きなドームを持つローレンシアン氷の複合体を支持しています.
- GIAモデルは,観測された静的重力場の25〜45%を占めています.
結論:
- GRACEのデータは,GIAとローレンツの氷床の構成の明確なイメージを提供します.
- この発見は,大陸のテキトスフィアの浮力を理解するための重要な境界条件を提供する.
- この研究は,氷河期後の反発とマントルのダイナミクスの地球物理モデルを精錬する.
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