西南極の氷床の過去と将来の接地線後退
1Geophysics Program, University of Washington, Seattle, WA 98195, USA. Institute for Quaternary Studies and Department of Geological Sciences, University of Maine, Orono, ME 04469, USA. Department of Geology and Geophysics, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA.
まとめ
西南極の氷床 (WAIS) は,ホロセンの初期から後退しています. この脱氷の歴史は,外部の気候強制なしにWAISの継続的な衰退が起こる可能性があることを示唆しています.
科学分野:
- 氷河学 氷河学とは
- 古代気候学 (paleoclimatology) とは,古代気候学 (paleoclimatology) とは,古代気候学 (paleoclimatology) とは,古代気候学 (paleoclimatology) とは,古代気候学 (paleoclimatology) とは
- 南極研究南極研究
背景:
- 西南極氷床 (WAIS) の脱氷の歴史を理解することは,その将来の安定性を予測するために極めて重要です.
- 過去の氷床の振る舞いは,環境変化への反応に関する洞察を提供します.
研究 の 目的:
- WAISの脱氷の歴史を再構築するために.
- Ross Sea Embaymentの過去の接地線撤退のドライバーを調査するために.
主な方法:
- ロス海入り口内の3箇所での南向きの接地線移動の年代付け.
- ホロセンの気候と海面記録の分析.
主要な成果:
- WAISのグラウンドラインの景気後退の大部分は,ホロセンの中期から後半にかけて起こった.
- この景気後退は,海平面や気候に重大な影響を及ぼさずに起こった.
- 現在地線からの撤退は,長期にわたる,内部主導のプロセスの継続である可能性があります.
結論:
- WAISは,外部からの強制力とは無関係な不況の歴史を持っています.
- WAISの継続的な後退は,安定した気候と海面条件下でも可能である.
- 過去の脱氷パターンは,西南極の氷床の将来の不安定性の可能性を示唆しています.
関連する概念動画
Boundary Conditions: Lossless Lines
Consider a single-phase, two-wire, lossless transmission line terminated by an impedance at the receiving end and a source with Thevenin voltage and impedance at the sending end. The line, with length, has a surge impedance and wave velocity determined by the line's inductance and capacitance.
At the receiving end, the boundary condition states that the voltage equals the product of the receiving-end impedance and current. This relationship is expressed as a function of the incident and...
At the receiving end, the boundary condition states that the voltage equals the product of the receiving-end impedance and current. This relationship is expressed as a function of the incident and...
Distance Corrections
To achieve precise distance measurements, especially in surveying and construction, certain corrections must be applied to account for potential sources of error like the standardization errors, temperature variations, and slope adjustments.Standardization error emerges when measurement equipment undergoes changes, such as wear, repairs, or weather impacts. To address this, surveyors compare the equipment’s readings to a standard. This process identifies any deviation that might lead to...
Meridians
In surveying, meridians are vital reference lines to measure directions and establish accurate land orientations. Meridians run from the north to the south poles, providing a stable framework for angular measurements and mapping. Meridians are fundamental in survey design, with the primary types being astronomic, magnetic, and assumed meridians. Each type offers distinct benefits and limitations, selected based on the project's scale and precision needs.The astronomic meridian is aligned with...
Magnetic Declination
Magnetic declination is the angle between true north, which aligns with the Earth's rotational axis, and magnetic north, which follows the direction of the Earth's magnetic field. This discrepancy exists because the magnetic poles do not coincide with the geographic poles. The value of magnetic declination depends on the observer's location on Earth and is subject to changes over time due to the dynamic nature of the Earth's magnetic field.The declination is called eastern when magnetic north...
Latitudes and Departures
Latitudes and departures are essential concepts in surveying, providing a systematic way to analyze the projections of traverse lines. These projections allow surveyors to interpret a line's north-south and east-west components, which are crucial for precisely calculating areas, bearings, and lengths. Latitude is the north-south projection of a line, calculated as the product of the line's length and the cosine of its bearing. Departure, conversely, is the east-west projection obtained by...
Polar Coordinate System
The polar coordinate system provides a natural way to describe points in the plane when distances and directions are more meaningful than horizontal and vertical displacements. It is especially useful for modeling non-rectangular regions such as circles and spirals, where symmetry about a center point is easier to express than it is in a rectangular grid. A familiar example is a ship’s plan position indicator, which marks detected targets as dots positioned relative to the ship at the display’s...


