πŸ”Ž Ekman Spiral – Definition and Explanations

Introduction

The Ekman spiralthe logarithmic spiral represents the theoretical hodograph (by immersion) of the shear current induced by the constant wind stress on the surface of a homogeneous ocean at infinite depth and subject to the Coriolis effect.

This name was later adopted in various sciences related to the study of rotating fluids. border (A border is an imaginary line separating two areas, especially two…) firm. This model spiral (In mathematics, a spiral is a curve that begins at a central point and then fades away…) especially used meteorology (Meteorology is the study of atmospheric phenomena…) to determine the thickness estimate boundary layer (The boundary layer is the contact zone between a body and the surrounding fluid…) near-ground atmospheric flow from a formation (Formulation is an industrial activity consisting in the production of products…) equal to the benthic boundary layer of the ocean current near the bottom.

History

At the time of shipment Frame (1893-1896), attempt to join the north pole (Earth’s geographic North Pole, or simply the North Pole, is the highest point…)Norwegian Fridtjof Nansen observed that his ship (A ship is a boat intended for sea navigation, that is, planned…) caught in the package Arctic (The Arctic is the region surrounding, in, and around the Earth’s North Pole…) was systematically dragged to the right the wind (Wind is the movement of the atmosphere, the mass of gas located on the surface…).

analysis of comments (Observation is the act of carefully watching events without the will to see them…)showed it was done after it was sent speed (We notice πŸ™‚ ship drift and ice the sea (The term sea encompasses several realities.) of ice pack (The ice mass is the width of the frozen sea. During the polar winter,…) (there are no icebergs in this part of the Arctic) was about 2% of the wind, but in a different direction 20Β° hour 40Β° on his right. Nansen communicated these results to Wilhelm Bjerknes, a Swede who was a professor at the time fluid mechanics (Fluid mechanics is the branch of physics that studies fluid flows…) At the University of Oslo and one of the pioneers of modern meteorology, Sweden, Wagn invited Walfrid Ekman to look at this question in order to explain this deviation in this direction.

So Ekman supported him thesis (Thesis (translated from Greek thesis, “the act of posing”) …) In 1902, by investigating the effect of wind friction surface (Surface generally refers to the surface layer of an object. The term a…) it was assumed plane (A plane is a tool for woodworking. It consists of a knife like this…) of one the ocean (In geography, an ocean is often defined as a large body of water…) homogeneous with constant viscosity. He demonstrated that the drift to the right of the wind direction was due to the balance between the winds tension (Tension is a stretching force.) wind on the surface (friction force) and Coriolis force (The Coriolis force is an inertial force acting perpendicular to the direction of…) operates on transportation (Transportation is the act of moving something or someone from one place to another, most often…) of all mass (The term mass is used to define two quantities related to one another…) moving water, also called Ekman transport. Ekman thus defines the spiral that bears his name; this gives an outward drift current on the surface 45Β° to the right of the wind direction in the hemisphere north (North is the cardinal point against south.) (Left in Southern Hemisphere).

In the air

Atmospheric circulation (Atmospheric circulation is motion on a planetary scale…) with and without friction: the resulting Ekman spiral

The spiral is the result of this power (The word force can designate a mechanical force on things, but also figuratively …) Coriolis, viscosity fluid (A liquid is a perfectly deformable material medium. We group under it…) and boundary surface friction. Like a liquidweather (Air is a mixture of gases that make up the Earth’s atmosphere. Odorless and…) is subjected to two forces in a rotating frame of reference: the difference pressure (Pressure is a basic physical concept. You can think of it as a force expressed…) which forces it to move toward lower pressures and the Coriolis force.

The movement is initially provided by the pressure force, the mass of air “falling” into the vacuum well. Coriolis force, which is the result of rotation, not a real force Place (Earth is the third planet in the solar system in order of distance…) on the motion of such a particle appearance (Sight is the sense that allows us to observe and analyze the environment through perception and…) From an observer on the ground, this movement is essentially perpendicular to the “deflection”. displacement (In geometry, displacement is similarity that preserves distances and angles…) weather. In the Northern Hemisphere, the deflection points to the right, towards the low pressure center. At equilibrium, the current flows along the isobars without friction. This phenomenon is described by geostrophic wind equations and shows the periodicity of such structures in particular: wave (A wave is the spread of anxiety that changes its path…) Rossby.

This is roughly what we see in the upper left of the following figure troposphere (The troposphere is the part of the Earth’s atmosphere located between the Earth’s surface and ….) above the layer where soil friction occurs (500 m hour 3 km stay depending on the terrain). However, in this boundary layer, friction adds to the balance of forces (lower left part of the line), but in the opposite direction of displacement. This slows down the air mass falling into the low pressure well (similarly to a satellite (May refer to satellite πŸ™‚ in lower orbit (Low Earth orbit (LEO) is a type of Earth orbit that…) out of order engine (An engine (Latin mōtor: “that moves”) is a device…) would fall to the earth’s surface as a result of friction with the atmosphere).

The right part of the drawing shows us the change in speed amplitude (In this simple wave equation πŸ™‚ and according to directionheight (Elevation is the vertical height of a place or object relative to the level…). Friction is maximum on the ground and the spreading effect is reduced by the viscosity of the fluid. zero (The number zero (derived from Italian zero, Arabic zero,…) gradually rises. Thus, the direction of the winds turns to the left, towards the center of low pressure in the northern hemisphere, between the upper part of the boundary layer and the ground.

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