主要な熱帯サイクロンの下での空海運動量交換のボトムアップ決定
Ewa Jarosz1, Douglas A Mitchell, David W Wang
1Naval Research Laboratory, Stennis Space Center, MS 39529-5004, USA. ewa.jarosz@nrlssc.navy.mil
まとめ
熱帯サイクロンの正確な予測は極めて重要です. この研究では,大気海運動量交換を推定し,主要サイクロン中の風速32m/sで耐力係数がピークに達することを発見しました.
科学分野:
- 海洋学と大気科学で,空気と海の相互作用のダイナミクスに焦点を当てています.
背景:
- 熱帯サイクロンの頻度と強度の増加により,予測モデルの改善が求められています.
- サイクロンの進化と海洋の反応の正確な予測は,沿岸の安全と財産保護に不可欠です.
研究 の 目的:
- 空海運動量交換を正確に評価することによって,熱帯サイクロンの予測を強化する.
- 主要な熱帯サイクロンイベントの際に,異なる風速の下での抵抗係数を定量化するために.
主な方法:
- 主要な熱帯サイクロンイベントからの直接観測を利用した.
- 海洋の視点から,海と空間のインターフェースで推定される運動量移転.
- 抵抗係数を風速との関係で分析した.
主要な成果:
- 耐力係数は,風速が毎秒20~48mの範囲で上昇することが観察されました.
- 耐力係数のピークは,約32m/sで確認されました.
- その後,ピークを超えたより高い風速で抵抗係数が減少した.
結論:
- この研究は,空気と海の運動量交換,特に激しい熱帯サイクロン中のドラッグ係数の行動に関する重要なデータを提供します.
- 発見は,サイクロンに対する海洋の反応のより正確なモデリングに貢献し,よりよいリスク評価と沿岸地域の緩和戦略を支援します.
関連する概念動画
Magnetostatic Boundary Conditions
An electric field suffers a discontinuity at a surface charge. Similarly, a magnetic field is discontinuous at a surface current. The perpendicular component of a magnetic field is continuous across the interface of two magnetic mediums. In contrast, its parallel component, perpendicular to the current, is discontinuous by the amount equal to the product of the vacuum permeability and the surface current. Like the scalar potential in electrostatics, the vector potential is also continuous...
Variation of Atmospheric Pressure
Change in atmospheric pressure with height is particularly interesting. The decrease in atmospheric pressure with increasing altitude is due to the decreasing gravitational force per unit area as we move away from the surface of the earth.
Assuming the air temperature is constant at a given altitude and that the ideal gas law of thermodynamics describes the atmosphere to a good approximation, one can find the variation of atmospheric pressure with height.
Let p(y) be the atmospheric pressure at...
Assuming the air temperature is constant at a given altitude and that the ideal gas law of thermodynamics describes the atmosphere to a good approximation, one can find the variation of atmospheric pressure with height.
Let p(y) be the atmospheric pressure at...
Moment-of-Momentum Equation
The moment-of-momentum equation is a critical tool for analyzing the torque produced by the rotating blades of a wind turbine. This equation is derived by applying Newton's second law to a fluid particle, which states that the rate of change of linear momentum is equal to the external force acting on the particle.
General External Flow Characteristics
The study of external flow is essential for creating structures and objects that interact efficiently and safely with moving fluids, such as air or water. When a body is immersed in a flowing fluid, it experiences two primary forces: drag, which opposes motion along the flow direction, and lift, which acts perpendicular to the flow. The shape, size, and orientation of the object influence these forces.Streamlined and Blunt Bodies in External FlowObjects in fluid flow are classified as...
Boundary Layer Characteristics
When a fluid encounters a solid surface, a boundary layer forms due to the interaction between the fluid's motion and the stationary surface. This phenomenon is characterized by a thin region adjacent to the surface where viscous forces dominate, influencing the fluid's velocity profile. The development of the boundary layer begins at the leading edge of the surface and evolves as the fluid moves downstream.As the fluid flows over the surface, friction between the fluid and the wall slows down...
Surface Integrals of Vector Fields: Flux
Understanding the movement of air masses is fundamental to meteorological analysis and atmospheric modeling. A key component in this process is quantifying the total mass of air that flows into or out of a defined region over a specified period of time. This is achieved by evaluating the mass flux across a boundary surface, a conceptual tool that simplifies the complex dynamics of atmospheric systems.To begin, an imaginary boundary surface S is introduced, enclosing the region of interest. The...


