Background on currents

The continuous motion of water is a major characteristic of the World Ocean. Water-mass movement in horizontal and vertical directions forms the general system of Ocean circulation. Deposition, evaporation, coastal drainage, horizontal non-uniformity of water density, tides, wind and atmospheric pressure are all related to a number of factors which cause a transitional motion of waters at the Ocean. With the origin of motion, there is a declining force of rotation of the Earth (Coriolis effect), which inclines the forced weight of water to the right in the Northern hemisphere and to the left in the Southern Hemisphere.

 

Circulation of surface waters is now one of the most investigated topics. Circulation represents a rotational system around a fixed geographical point. Each rotation permits the interconnected currents to widen, and increases the speed and volume, thereby mixing the waters.

One of the largest currents on the globe is the West Wind Drift, or Antarctic Circumpolar current. It is about 2,500 km wide with a maximum speed of 0.4-0.5 m/sec, and has a volume measured in the Drake Passage of 230 million m3/sec. The Gulf Stream current has a volume on the order of 80 million m/sec, and the Kuroshio current, 50-60 million m3/sec. The greatest speed of these currents2-3 m/sec.