What do you mean by Ekman spiral?

What do you mean by Ekman spiral?

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 is upwelling?

Upwelling is a process in which deep, cold water rises toward the surface. Upwelling occurs in the open ocean and along coastlines. The reverse process, called “downwelling,” also occurs when wind causes surface water to build up along a coastline and the surface water eventually sinks toward the bottom.

How does Ekman transport affect upwelling?

In the Northern Hemisphere, upwelling occurs on west coasts when winds are blowing north to south. Ekman transport and the Coriolis Effect make the coastal waters move, on average, 90 degrees to the wind. This, in turn, pulls deep water up to the surface to replace the original surface water.

Where does Ekman driven upwelling occur?

Ekman suction occurs both along coastlines and in the open ocean, but also occurs along the equator. Along the Pacific coastline of California, Central America, and Peru, as well as along the Atlantic coastline of Africa there are areas of upwelling due to Ekman suction, as the currents move equatorwards.

What is the Ekman spiral and what is its cause?

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. As a result, each successively deeper layer of water moves more slowly to the right or left, creating a spiral effect.

What is the difference between the Ekman spiral and Ekman transport?

The net transport of water through the entire wind-driven column (Ekman transport) is 90 degrees to the right of the wind. The Ekman spiral indicates that each moving layer is deflected to the right of the overlying layer’s movement; hence, the direction of water movement changes with increasing depth.

Why are upwellings important?

Because the deep water brought to the surface is often rich in nutrients, coastal upwelling supports the growth of seaweed and plankton. These, in turn, provide food for fish, marine mammals, and birds. Upwelling generates some of the world’s most fertile ecosystems.

Why are upwellings and Downwellings important for marine environments?

Currents also are a major factor in ocean ecosystems. Two types of current motion, upwelling and downwelling, strongly influence the distribution and abundance of marine life. When currents upwell, or flow up to the surface from beneath, they sweep vital nutrients back to where they’re needed most.

How do Downwellings and upwellings affect nutrient and oxygen contents?

Downwelling is where surface water is forced downwards, where it may deliver oxygen to deeper water. As the surface waters diverge, deeper water must be brought to the surface to replace it, creating upwelling zones. The upwelled water is cold and rich in nutrients, leading to high productivity.

What is the Ekman spiral How is it created what are the forces involved?

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.

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 does the Ekman spiral describe quizlet?

Ekman spiral. A thoretical model of the effect on water of wind blowing over the ocean. Due to the Coriolis effect, the surface layer is expected to drift 45 degrees to the right or left of the wind. Water at lower layers drifts to the right or left, though not as fast as the layers above it due to friction.

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.

What is the net movement of water in the Ekman spiral?

Each successive layer of water is moved and deflected by the layer above, creating a spiraling pattern of water movement that diminishes with depth. The net movement of the water within the spiral is 90 o relative to the wind direction (red arrow) (Modified by PW from Ekman spiral By Schlusenbach (unbekannt) [Public domain], via Wikimedia Commons).

Where does Ekman upwelling and downwelling take place?

(d) Open ocean In a typical ocean basin, convergence and divergence of Ekman velocities leads to Ekman upwelling in the subpolar ocean and Ekman downwelling in the subtropical ocean. This sets the interior ocean below in motion…

How are Ekman currents generated in the ocean?

Summary of key points • Surface winds input momentum from the atmosphere into a surface Ekman layer of the ocean. • Horizontal Ekman transports are generated at a right angle to the surface winds through a balance between wind stress and the Coriolis force.