Ocean Currents

Also found in: Dictionary, Thesaurus.
Related to Ocean Currents: El Nino
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

Ocean Currents


translatory movements of masses of water in the seas and oceans. On the surface of the ocean they spread out into a broad band and encompass a layer of water of a certain depth. At great depths and on the bottom there are significantly slower movements of water particles in a certain general direction, usually opposite that of the surface current, that constitute part of the general circulation of water in the world’s oceans.

Ocean currents are caused by the force of friction between the water and the air moving over the surface of the sea, by pressure gradients arising in the water, and by the tide-forming forces of the moon and sun. The force of the earth’s rotation considerably affects the direction of currents, causing them to be deflected to the right in the northern hemisphere and to the left in the southern hemisphere.

Ocean currents are distinguished by origin, location, physical characteristics, and stability. Wind currents, or drift currents, are the main form of movement of the surface layer of water in oceans and seas and frequently lead to the development of gradient currents. Convection currents, or density currents, are a variety of gradient currents. Runoff and compensation currents are also distinguished. Surface, subsurface, intermediate, deep, and bottom currents are distinguished according to location.

According to their physicochemical characteristics, a distinction is made between warm and cold currents and between salt-water and freshwater currents. The subdivision according to physical (thermal) characteristics is to some degree arbitrary. If the water temperature of a current is higher than the temperature of the surrounding waters, the current is called warm; if the temperature is lower, the current is called cold. Warm currents move from low latitudes to high latitudes, and cold currents move in the opposite direction. In terms of variability, ocean currents may be permanent (stable), seasonal, and periodic (of tidal origin). Permanent and seasonal currents may be of the drift, runoff, density, or pressure-gradient types. Examples of permanent currents are the northern and southern equatorial currents and the Gulf Stream; the monsoon currents of the northern part of the Indian Ocean, which change direction with the summer and winter monsoons, are examples of seasonal currents. Currents entirely caused by any one of the factors mentioned above are rarely observed in the oceans; the most clearly marked currents in the world’s oceans are caused by a combination of several factors. For example, the Gulf Stream is a density, wind, and runoff current.

Modern research on ocean currents is aimed at direct measurement at various depths using automatic recording instruments, neutral-buoyancy floats, and parachute floats. Researchers from a number of countries, among them the USSR, the USA, and Japan, have carried out many long-term observations of currents in the world’s oceans, including observation of deep currents using moored buoy stations. The observations have made it possible to estimate the variability of currents over time and to determine the basic principles of such variation. Direct instrument measurements of currents have led to the discovery of powerful, previously unknown currents in the ocean (the Cromwell Current in the Pacific Ocean, the Lomonosov Current in the Atlantic, and the deep countercurrents under the Gulf Stream and the Japan Current, or Kuroshio). Indirect methods of analysis (by distribution of temperature, salinity, and density) and numerical methods, which make it possible to calculate the direction and velocity of currents on the basis of the wind field or by distribution of water density at the surface and at the depths of the ocean, play a large role in the study of currents.


Zubov, N. N. Dinamicheskaia okeanologiia. Moscow, 1947.
Shtokman, V. B. Ekvatorial’nye protivotecheniia v okeanakh. Moscow, 1948.
Shuleikin, V. V. Fizika moria, 3rd ed. Moscow, 1953.
Evgenov, N. I. Morskie techeniia, 2nd ed. Leningrad, 1957.
Lineikin, P. S. Osnovnye voprosy dinamicheskoi teorii baroklinnogo sloia moria. Leningrad, 1957.
Morskoi atlas, vol. 2. Leningrad, 1953.
Fel’zenbaum, A. I. Teoreticheskie osnovy i metody rascheta ustanovivshikhsia morskikh techenii. Moscow, 1960.
Sarkisian, A. S. Osnovy teorii i raschet okeanicheskikh techenii. Leningrad, 1966.
Kamenkovich, V. M. Osnovy dinamiki okeana. Leningrad, 1973.


The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.
References in periodicals archive ?
While this use of "gyre" is increasingly common, the term traditionally refers simply to large rotating ocean currents.
Our preliminary results have revealed that horizontal and vertical ocean currents are closely linked.
However, whereas temperatures in Greenland responded quickly to the ocean current shutdown and subsequent reboot 1,000 years later, it took hundreds of years for rainfall in the Philippines to be affected and to recover.
The results of this study shed light on why icebergs of different sizes follow different drift patterns under the same ocean currents and winds.
According to the model, wind and ocean currents often transport melt water around the southern tip of Greenland on a westward journey that can take upward of 60 days.
Boyan Slat's solar-powered design (rendering, bottom) uses ocean currents to gather plastics for recycling.
IHI and Toshiba, together with the University of Tokyo and Mitsui Global Strategic Studies Institute, have conducted R&D financed by Nedo's "R&D of Ocean Energy Technology - R&D of Next-Generation Ocean Energy Power Generation (Underwater Floating Type Ocean Current Turbine System)" programme since fiscal year 2011.
However, now researchers report that the deep ocean currents that move heat around the globe stalled or may have stopped at that time, possibly due to expanding ice cover in the Northern Hemisphere.
As well as the Bluefin-21, authorities are relying on daily modeling of ocean currents provided by the Commonwealth Scientific and Industrial Research Organization's (CSIRO) Marine and Atmospheric Research unit, which may give clues about how any surface debris may have dispersed.
Measuring Ocean Currents: Tools, Technologies, and Data
At her current post, Skemp works on testing and evaluating the potential of ocean currents to create electricity through ocean current hydrokinetic and ocean thermal energy conversion.

Full browser ?