南極の氷河川の流れ方向の切り替え
H Conway1, G Catania, C F Raymond
1Earth and Space Sciences, University of Washington, Seattle, Washington 98195, USA. conway@ess.washington.edu
Nature
|October 9, 2002
まとめ
西南極の氷河流は非常にダイナミックで,氷の流れは急速に再編成されます. この研究は,ロス排水システムにおける重要な流れスイッチを明らかにし,氷床の質量バランスに影響を与えています.
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:
- 南極西部の急流の氷河流は,氷床の質量バランスにとって極めて重要です.
- 以前の研究では,主に氷河流Cの減速が原因で,ロス海セクターで質量バランスが正であることを示した.
研究 の 目的:
- ロス排水システムのダイナミックな振る舞いを調査するために.
- 変化する氷の流れパターンの背後にある理由を理解するために.
主な方法:
- 表面測定とリモートセンシングデータを活用した.
- 氷河の流れの活動と構成の変化を分析した.
主要な成果:
- ロス排水システムの高度なダイナミック性を実証した.
- 氷河流の方向転換を記録した. 氷河流Cからウィランズ氷河流 (旧氷河流B) へ.
- このスイッチは,ウィランス氷河の進行中の薄めと,最近の氷河の厚み増加に起因する.
結論:
- 西南極の氷河の流れは,急速に再編成することができます.
- 将来の急激な氷河の再構成は,内部ダイナミクスと気候変動のために予想されます.
- 短期的な質量変化の観測は,大規模な氷床質量バランスを評価するために慎重に解釈する必要があります.
関連する概念動画
Steady Flow of a Fluid Stream
972
Consider a control volume, such as a pipe with solid boundaries, through which fluid flows and changes direction due to the impulse exerted by the resulting force from the pipe walls. In steady flow, the mass of fluid entering the control volume at a given time, t, with velocity v1, is equal to the mass leaving after infinitesimal time dt, with velocity v2.
During this process, the momentum of the fluid within the control volume remains constant over the time interval dt. By applying the...
During this process, the momentum of the fluid within the control volume remains constant over the time interval dt. By applying the...
972
Irrotational Flow
1.3K
Irrotational flow is characterized by fluid motion where particles do not rotate around their axes, resulting in zero vorticity. For a flow to be irrotational, the curl of the velocity field must be zero. This imposes specific conditions on velocity gradients. For instance, to maintain zero rotation about the z-axis, the gradient condition:
1.3K
Rapidly Varying Flow
731
Rapidly varying flow (RVF) in open channels is characterized by abrupt changes in flow depth over a short distance, with the rate of depth change relative to distance often approaching unity. These flows are inherently complex due to their transient and multi-dimensional nature, making exact analysis difficult. However, approximate solutions using simplified models provide valuable insights into their behavior.Key Features of Rapidly Varying FlowRVF is commonly observed in scenarios involving...
731
Underflow Gates
558
Underflow gates are vital for controlling water flow in irrigation canals. The three main types of underflow gates — vertical, radial, and drum gates — serve different purposes while ensuring effective flow management. Vertical gates move up and down, generating a free-flowing water jet; radial gates pivot to regulate the flow; and drum gates rotate for precise adjustments. The flow through these gates is influenced by downstream conditions, resulting in free or drowned outflow.Free and...
558
Surface Appendages of Archaea
873
Archaeal surface appendages are highly specialized structures essential for environmental adaptation, encompassing roles in adhesion, biofilm formation, and motility. Among these appendages, pili and archaella stand out for their distinct morphologies and functionalities, enabling archaea to thrive in diverse and often extreme environments.Pili: Adhesion and Biofilm FormationPili are filamentous structures assembled from pilin protein subunits, primarily contributing to adhesion and biofilm...
873
Net Change Theorem
220
The Net Change Theorem is a fundamental principle in calculus that establishes a direct relationship between a function’s rate of change and its accumulated change over an interval. Mathematically, it states that the definite integral of a function's derivative over a given interval [a,b] yields the net change in the original function:This theorem has significant applications in various real-world scenarios, including physics, economics, and engineering. A particularly useful application...
220


