地球の角運動の予算は,サブシーズンの時間スケールで計算されます
まとめ
大気のトルクが不規則な昼間の変化 (LOD) を引き起こします. LODと大気角運動量 (AAM) の間には8日間の期間まで一貫性がありますが,より短い期間は騒音により一貫性が欠けています.
科学分野:
- 地質物理学 地質物理学とは地質物理学です.
- 大気科学 大気科学
- 天文学 (astronomy) 天文学 (astronomy) とは,天文学 (astronomy) とは,天文学 (astronomy) とは,天文学 (astronomy) とは
背景:
- 不規則な昼間 (LOD) の変動は,主に大気のトルクによって引き起こされます.
- 地球の自転の変動を理解することは,正確なタイムキーピングと地球物理学の研究に不可欠です.
研究 の 目的:
- 昼間の長さ (LOD) の変動と大気の角度運動量 (AAM) の間の関係を調査する.
- 異なる時間スケールでのLODとAAMデータにおける不一致の原因を特定する.
主な方法:
- LODとAAMのタイムシリーズデータの分析.
- 異なる期間のLODとAAMの相関を判別するための一貫性分析.
- 地球の自転変動に関する既存のモデルのレビュー.
主要な成果:
- LODとAAMのタイムシリーズの間で,8日間の期間まで有意な一貫性が観察されました.
- 短期間での一貫性の欠如は,両方のデータセットにおける信号対ノイズ比の低下に起因する.
- 潮による地球の自転の変動に関する既存のモデルは,海洋的影響を含めるために精細化する必要があるかもしれません.
結論:
- 大気中の過程は,短期的なLODの変動に大きく貢献しています.
- LODとAAMの間の不一致を解決するためにさらなる研究が必要であり,海洋の影響やモデル化されていない角運動量成分を含む可能性があります.
関連する概念動画
Angular Momentum
Angular momentum characterizes an object's rotational motion and is defined as the moment of its linear momentum about a specified point O. When a particle moves along a curved path in the x-y plane, the scalar formulation calculates the magnitude of its angular momentum, utilizing the moment arm (d), representing the perpendicular distance from point O to the line of action of the linear momentum. Despite being scalar in formulation, angular momentum is inherently a vector quantity. Its...
Angular Momentum: Single Particle
Angular momentum is directed perpendicular to the plane of the rotation, and its magnitude depends on the choice of the origin. The perpendicular vector joining the linear momentum vector of an object to the origin is called the “lever arm.” If the lever arm and linear momentum are collinear, then the magnitude of the angular momentum is zero. Therefore, in this case, the object rotates about the origin such that it lies on the rim of the circumference defined by the lever arm magnitude.
The...
The...
Conservation of Angular Momentum
A system's total angular momentum remains constant if the net external torque acting on the system is zero. Considering a system that consists of n tiny particles, the angular momentum of any tiny particle may change, but the system's total angular momentum would remain constant. The principle of conservation of angular momentum only considers the net external torque acting on the system. While there are internal forces exerted by different particles within the system that also produce internal...
Conservation of Angular Momentum: Application
A system's total angular momentum remains constant if the net external torque acting on the system is zero. Examples of such systems include a freely spinning bicycle tire that slows over time due to torque arising from friction, or the slowing of Earth's rotation over millions of years due to frictional forces exerted on tidal deformations. However in the absence of a net external torque, the angular momentum remains conserved. The conservation of angular momentum principle requires a change...
Gyroscope: Precession
Precession can be demonstrated effectively through a spinning top. If a spinning top is placed on a flat surface near the surface of the Earth at a vertical angle and is not spinning, it will fall over due to the force of gravity producing a torque acting on its center of mass. However, if the top is spinning on its axis, it precesses about the vertical direction, rather than topple over due to this torque. Precessional motion is a combination of a steady circular motion of the axis and the...
Apparent Weight and the Earth's Rotation
Since all objects on the Earth's surface move through a circle every 24 hours, there must be a net centripetal force on each object, directed towards the center of that circle. The points of the north and south poles are the only exception to this rule.
For an object on the Earth's equator, the net centripetal force that accounts for its rotation is the Earth's pull towards its center, or the weight minus the normal force that prevents it from piercing into the Earth's surface. This force,...
For an object on the Earth's equator, the net centripetal force that accounts for its rotation is the Earth's pull towards its center, or the weight minus the normal force that prevents it from piercing into the Earth's surface. This force,...


