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Currents

Ocean Currents And Climate

The oceans cover over 70% of Earth's surface. In the tropics, ocean water absorbs heat from the atmosphere. As the warmed water is carried north by surface currents, immense amounts of stored energy, in the form of heat, are transferred from one part of the world to another, contributing to weather and climate patterns. For example, the Gulf Stream carries warm water far up the eastern coast of North America, and then swings east, towards Europe. The warm water of the Gulf Stream heats the air above it, creating a warmer climate for Iceland and western Europe than would otherwise exist. Thermohaline currents also carry stored heat from the tropics to the mid-latitudes.

Oceanographers and climatologists are still exploring the important relationships between the oceans and their currents and ongoing global climate change due to greeenhouse gases. Much of the heat resulting from global warming is being stored in the oceans, according to scientists, thus delaying part of the surface warming global climate change theorists have expected to see as the result of human-induced increases in greenhouse gases in the atmosphere. The heat being stored by ocean waters will contribute to warming trends throughout the world as the water is circulated by oceanic currents.

Resources

Books

Davis, Richard A., Jr. Oceanography, An Introduction to the Marine Environment. Dubuque, IA: William C, Brown Publishers, 1991.

Goudie, Andrew, ed. The Encyclopaedic Dictionary of Physical Geography. New York: Blackwell Reference, 1985.

Groves, Donald G., and Lee M. Hunt. Ocean World Encyclopedia. New York: McGraw-Hill Book Company, 1980.

Hendrickson, Robert. The Ocean Almanac. Garden City, New York: Doubleday and Company, 1984.

Ocean Science. San Francisco: W. H. Freeman and Company, 1977.

Pinet, Paul. Invitation to Oceanography. 2nd ed. Boston: Jones & Bartlett Pub., 1999.

Thurman, Harold V., and Alan P. Trujillo. Essentials of Oceanography. 7th ed. Englewood Cliffs, NJ: Prentice Hall, 2001.

KEY TERMS

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Coriolis effect: —Generically, this force affects particles traveling on a rotating sphere. As it pertains to currents, it is a deflection of water caused by the turning of the earth. At the equator, the effect is nonexistent but it gets stronger toward the poles. Water tends to swirl to the right in the Northern Hemisphere and to the left in the Southern Hemisphere.
Gyre: —Typically elliptical in shape, a gyre is a surface ocean current that results from a combination of factors, including: the Coriolis effect, the earth's rotation, and surface winds.
Rip currents: —Narrow areas in the ocean where water flows rapidly out to sea. The flow is swift in order to balance the consistent flow of water toward the beach brought by waves.
Thermohaline circulation: —The flow of water caused by variations in water density rather than caused by the wind. In certain situations, colder water from the sea floor mixes upward with the warmer water. As it does this, it rotates faster, moving toward the two poles.
Turbidity currents: —Local, rapid-moving currents that result from water heavy with suspended sediment mixing with lighter, clearer water. Causes of turbidity currents are earthquakes or when too much sediment piles up on a steep underwater slope. They can move like avalanches.

Additional topics

Science EncyclopediaScience & Philosophy: Cosine to Cyano groupCurrents - Surface Currents, Tidal Currents, Deep Water (or Density) Currents, Measuring Currents, Ocean Currents And Climate - Turbidity currents