What is the Ekman flow?
Ek·man flow (ĕk′mən) Current flow in one layer of a fluid brought about by current flow in an adjacent layer, as when surface ocean currents caused by wind themselves cause current flow deeper in the ocean. Also called Ekman transport. [After Vagn Walfrid Ekman (1874-1954), Swedish oceanographer.]
What is the Ekman spiral explain why Ekman transport occurs and what role it plays in producing oceanic gyres in the surface waters of the subtropical oceans?
Ekman transport occurs when ocean surface waters are influenced by the friction force acting on them via the wind. As the wind blows it casts a friction force on the ocean surface that drags the upper 10-100m of the water column with it.
What are the layers of water referred to in an Ekman spiral?
Ekman layer, a vertical region of the ocean affected by the movement of wind-driven surface waters. This layer, named for the Swedish oceanographer V. Walfrid Ekman, extends to a depth of about 100 metres (about 300 feet). This phenomenon is called Ekman transport, and its effects are widely observed in the oceans.
How are Ekman spirals formed?
When surface water molecules move by the force of the wind, they, in turn, drag deeper layers of water molecules below them. As a result, each successively deeper layer of water moves more slowly to the right or left, creating a spiral effect.
What does the Ekman spiral describe?
An Ekman spiral (A) is a rotating column of water that forms when water moves at an angle to the wind direction due to the Coriolis Effect. The net effect of the rotating water (B) is movement at right angle to the wind direction. The water turns to the left instead of right in the Southern Hemisphere.
What does the Ekman spiral describe quizlet?
Ekman spiral: Wind creates a surface current that spirals in a clockwise direction as depth decreases, flowing in the opposite direction of the wind at about 100m depth. ( spiral is in the opposite direction in the southern hemisphere)
What is the base of Ekman layer?
The lowermost layer of the atmosphere or the ocean, adjacent to the land surface in the case of the atmosphere or to the ocean bottom in the case of the ocean, in which the direction of flow turns gradually from the direction of the overlying geostrophic flow, is called the Ekman layer (or the bottom Ekman layer).
Where do Ekman spirals occur?
The first documented observations of an oceanic Ekman spiral were made in the Arctic Ocean from a drifting ice flow in 1958. More recent observations include: SCUBA diving observations during a study of upwelling water transport through a kelp forest on the west coast of South Africa in 1978.
Why does the Ekman spiral happen Which way does it twist in the North Atlantic?
Why does the Ekman spiral happen? Which way does it twist in the North Atlantic? Because the deeper the current, the more it is deflected compared with the surface current. The movement of dense, cold, salty water from the abyssal regions to the surface.
What is true Ekman transport?
Ekman transport is to the right of the wind direction in the Northern Hemisphere. The Coriolis effect causes surface waters to move at an angle relative to the wind direction. In the deeper layers of the Ekman spiral, water can move in a direction opposite of the wind direction.
How are the layers of the Ekman spiral displaced?
Ekman spiral. According to the concept proposed by the 20th-century Swedish oceanographer V.W. Ekman, the surface layers are displaced 45° to the right in the Northern Hemisphere (45° to the left in the Southern Hemisphere), and successively deeper layers are further displaced so that at a given depth the water motion is opposite to wind direction.
How did the Ekman spiral get its name?
Click the image for a larger view. The Ekman spiral, named after Swedish scientist Vagn Walfrid Ekman (1874-1954) who first theorized it in 1902, is a consequence of the Coriolis effect. When surface water molecules move by the force of the wind, they, in turn, drag deeper layers of water molecules below them.
How does Ekman transport affect the surface of water?
In coastal areas where prevailing winds blow along the coast, Ekman transport causes surface water to flow offshore. This movement of water away from the coast at the surface causes deeper water to upwell. This upwelled water tends to be rich in nutrients, making coastal upwelling zones highly productive areas.
How does the Ekman transport affect the gyre?
The Ekman transport piles up water in the center of the gyre, making the water level higher in the gyre center than on the edges of the gyres. This pile of water then has a tendency to flow back “downhill” due to gravity. As the water flows “downhill” away from the gyre center, it is deflected to the right by the Coriolis force.