How does ekman transport work

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 example shown above is for the Northern Hemisphere. In the overall process of upwelling , winds blow across the sea surface at a particular direction, which causes a wind-water interaction. As a result of the wind, the water is transported a net of 90 degrees from the direction of the wind due to Coriolis forces and Ekman transport.

Ekman Sprial. Asked by: Virtudes Lupenkov science environment How does the Ekman transport work? Last Updated: 31st May, 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 m of the water column with it. Alfred Migueles Professional. What is the maximum depth of the Ekman spiral? At a depth of about to m to ft , the Ekman spiral has gone through less than half a turn. Gus Hainke Professional. What is Ekman theory? Ekman theory explains the theoretical state of circulation if water currents were driven only by the transfer of momentum from the wind.

Judit Aristregui Professional. What forces cause the Ekman spiral? The Ekman spiral , named after Swedish scientist Vagn Walfrid Ekman who first theorized it in , 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.

Facundo Sonneborn Explainer. What factors drive Ekman transport? Surface currents form circular patterns in the major ocean basins called "gyres. Velko Thielcke Explainer. What causes upwelling? Upwelling occurs when winds blowing across the ocean surface push water away from an area and subsurface water rises up to replace the diverging surface water.

Major upwelling areas along the world's coasts are highlighted in red. Porsha Conen Explainer. Why is Ekman transport important? Coriolis and Ekman Transport. For large scale winds and ocean currents, the Coriolis effect is an important consideration because it changes the net direction of heat transport. A vector is an arrow representing a physical quantity so that length is directly proportional to magnitude and orientation represents direction.

This model is known as the Ekman spiral, named for the Swedish physicist V Walfrid Ekman who first described it mathematically in Ekman based his model on observations made by the Norwegian explorer Fridtjof Nansen Nansen was interested in ocean currents in polar seas. In , he allowed his m ft wooden ship, the Fram, to freeze into Arctic pack ice about km mi south of the North Pole.

His goal was to drift with the ice and cross the North Pole thereby determining how ocean currents affect the movement of pack ice. The Fram remained locked in pack ice for 35 months but only came within km mi of the North Pole.

As the Fram slowly drifted with the ice, Nansen noticed that the direction of ice and ship movement was consistently 20 to 40 degrees to the right of the prevailing wind direction.

Viewed from above in the Northern Hemisphere, the surface layer of water moves at 45 degrees to the right of the wind.

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. In an ideal case, a steady wind blowing across an ocean of unlimited depth and extent causes surface waters to move at an angle of 45 degrees to the right of the wind in the Northern Hemisphere 45 degrees to the left in the Southern Hemisphere.

Each successive layer moves more toward the right and at a slower speed. At a depth of about to m to ft , the Ekman spiral has gone through less than half a turn. In the Northern Hemisphere, the Ekman spiral predicts net water movement through a depth of about to m to ft at 90 degrees to the wind direction Figure B. 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. Wind blowing in the opposite direction pushes surface water towards the coast. As water piles up at the shore, it is forced down, creating downwelling. Eckman transport driven up and downwelling is not limited to coastal environments. In the open ocean, trade winds also caused Ekman transport.

Along the equator prevailing winds blow from east to west. This causes water to move away from the equator in both the northern and southern hemispheres. Diverging currents lower the water level right along the equator resulting in the upwelling of deeper water. Ekman transport causes water to pile up at mid-latitudes in the zone where prevailing winds transition from easterly to westerly, water piles up as the change in wind direction pushes surface currents towards each other. This convergence causes downwelling.

Just like along the coast, upwelling along the equator brings nutrient-rich water to the surface stimulating primary productivity. The piling up of water at mid-latitudes contributes to the formation of gyres that circulate in all of Earth's major ocean basins.

Follow SciencePrimer. Skip to main content. Video Overview Walford Ekman first investigated the movement of water in response to surface winds in