Ocean Circulation
About Ocean Circulation
Ocean circulation is a key regulator of climate by storing and transporting heat, carbon, nutrients and freshwater all around the world. Complex and diverse mechanisms interact with one another to produce this circulation and define its properties. Ocean circulation patterns, the movement of large masses of water both at and below the surface, are determined by atmospheric circulation patterns, variation in the amount of sunlight absorbed with latitude, and the water cycle. Surface currents, also called horizontal currents, are primarily the result of wind pushing on the surface of the water, and the direction and extent of their movement is determined by the distribution of continents. Currents, like winds in the atmosphere, do not move in straight lines because of the spin of the Earth, which causes the Coriolis effect.
But because the Earth rotates, circulating air is deflected. Instead of circulating in a straight pattern, the air deflects toward the right in the Northern Hemisphere and toward the left in the Southern Hemisphere, resulting in curved paths. This deflection is called the Coriolis effect.
The oceanic, wind driven Ekman spiral is the result of a force balance created by a shear stress force, Coriolis force and the water drag. This force balance gives a resulting current of the water different from the winds. In the ocean, there are two places where the Ekman spiral can be observed. It 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.
Coastal upwelling is the process by which strong winds blow down the coasts of continents and, in conjunction with the earth’s rotation, cause the surface waters to be pushed offshore. Water from the ocean depths is then pulled up - or upwelled - to the surface to take its place.
antarctic circumpolar current
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