Major Ocean Currents
» The water on the surface of the oceans is constantly flowing in one direction from one place to another. These flowing movements of water in oceans are called ocean currents.
» Ocean current, stream made up of horizontal and vertical components of the circulation system of ocean waters that is produced by gravity, wind friction, and water density variation in different parts of the ocean.
» The current's direction and speed depend on the shoreline and the ocean floor. They can flow for thousands of miles and are found in all the major oceans of the world.
» Ocean currents are similar to winds in the atmosphere in that they transfer significant amounts of heat from Earth’s equatorial areas to the poles and thus play important roles in determining the climates of coastal regions.
» Ocean currents flow for great distances, and together, create the global conveyor belt which plays a dominant role in determining the climate of many of the Earth’s regions.
» More specifically, ocean currents influence the temperature of the regions through which they travel.
» For example, warm currents travelling along more temperate coasts increase the temperature of the area by warming the sea breezes that blow over them.
» Perhaps the most striking example is the Gulf Stream, which makes north-west Europe much more temperate than any other region at the same latitude.
» Another example is Lima, Peru where the climate is cooler (sub-tropical) than the tropical latitudes in which the area is located, due to the effect of the Humboldt Current.
Based on their depth the ocean currents can also be divided into two categories:
· Ocean currents can be found on the water surface and deeper down.
· Currents on the surface often depend on the wind. They travel clockwise in the northern hemisphere. They travel counterclockwise in the southern hemisphere. They are found up to 400 metres (1,300 ft) below the surface of the ocean.
· Deeper currents depend on water pressure, temperature, and salt content.
Based on temperature. Ocean currents can broadly be divided into two classes—the warm and the cold currents.
Warm and Cold Oceanic Currents
· Warm ocean currents originate near the equator and move towards the poles or higher latitudes while cold currents originate near the poles or higher latitudes and move towards the tropics or lower latitude.
· Currents in the western part of every continent is cold. Currents coming from the polar region are generally cold. Currents near to equator are generally warm.
1. The Warm Currents: These are those currents which flow from the low latitudes in Tropical Zones towards the high latitudes in the Temperate and Subpolar Zones. They bring warm water into cold water areas.
2.The Cold Currents: These currents have a lower surface temperature and bring cold water into warm water areas. These currents flow in the high latitudes from the Polar regions towards the low latitudes in the warm Equator region.
Oceanic Currents in Different Oceans
Pacific Ocean Currents
1- Equatorial Current (Warm)
2- North Equatorial Current (Warm): Flows across from east to west, i.e., from North America it reaches the Philippines.
3- South Equatorial Current (Warm): Peru Current eventually joins with the South Equatorial Current and completes the circuit.
4- Peruvian Current (Cold): Cold current near the west coast of S. America.
5- Kuroshio or Japan Current and W Winds drift (warm) Current (warm): N. Eq. current along the Philippines, Taiwan & Japan coast form this current. From the S.E. Japan the current, under the influence of prevailing westerlies, flows right across the ocean.
6- California Current (Cold): It moves southward along the coast of California
7- Oyashio or Kuril Current (Cold): Flows along the east coast of Kamchatka peninsula.
8- South Pacific Current: From west to east and crosses the Pacific Ocean along with the West Wind Drift.
9- East Australian Current (Warm): Flows from east to west in S. Pacific Ocean.
Indian Ocean Current
The currents in the N. Indian Ocean differ entirely from the general pattern of circulation. They change their direction from season to season in response to the seasonal rhythm of the monsoons.
1- Equatorial Centre Current (Warm)
2- South Equatorial Current (Warm)
3- Mozambique and Agulhas Current (Warm)
4- Monsoon Current (Warm)
5- South Indian Current (Cold)
6- West Australian Current (cold)
Atlantic Ocean Currents
1- Benguela Current (Cold): Cold current from S. to N near the ‘Cape of Good Hope’
2- South Atlantic Current (Cold)
3- Brazil Current (Warm): Flows along the S. American coast from North to South
4- Labrador Current (Cold): Flows along the eastern coast of Canada, meets the warm Gulf Stream near the north-east corner of U.S.A.
5- North Equatorial Current (Warm)
6- South Equatorial Current (Warm)
7- Gulf Stream (Warm): Beyond the Cape Hatteras up to the Grand Banks of New Found Land, Florida current is known as Gulf Stream. From the Grand Banks, the Gulf Stream moves eastward across the Atlantic as the Atlantic Drift.
8- Equatorial Counter Current or Guinea Current (Warm): Flows off the W. African coast
List of Surface Ocean Currents
Major Surface Ocean Currents |
||
Name
|
Ocean
|
Type
|
Agulhas Current
|
Indian Ocean
|
Warm
|
Alaska Current
|
North Pacific Ocean
|
Warm
|
Benguela Current
|
South Atlantic Ocean
|
Warm/Cool
|
Brazil Current
|
South Atlantic Ocean
|
Warm
|
California Current
|
North Pacific Ocean
|
Cool
|
Canaries Current
|
North Atlantic Ocean
|
Cool
|
East Australian Current
|
South Pacific Ocean
|
Warm
|
Equatorial Current
|
Pacific Ocean
|
Warm
|
Gulf Stream
|
North Atlantic Ocean
|
Warm
|
Humboldt (Peru) Current
|
South Pacific Ocean
|
Cool
|
Kuroshio (Japan) Current
|
North Pacific Ocean
|
Warm
|
Labrador Current
|
North Atlantic Ocean
|
Cool
|
North Atlantic Drift
|
North Atlantic Ocean
|
Warm
|
North Pacific Drift
|
North Pacific Ocean
|
Warm
|
Oyashio (Kamchatka) Current
|
North Pacific Ocean
|
Cool
|
West Australian Current
|
Indian Ocean
|
Cool
|
West Wind Drift
|
South Pacific Ocean
|
Cool
|
Frequently asked questions:
What are the two types of currents in the ocean?
There are two type of Ocean Currents:
Surface Currents--Surface Circulation.
Deep Water Currents--Thermohaline Circulation.
Why is it important to know about ocean currents?
For the considerably longer periods– decades to millennia – which are relevant for climate change, the significantly larger heat capacity of the deep ocean is important. Ocean currents and mixing by winds and waves can transport and redistribute heat to deeper ocean layers.
What are the different ocean currents that carry warm water give at least three examples?
Western boundary currents are warm, deep, narrow, and fast flowing currents that form on the west side of ocean basins due to western intensification. They carry warm water from the tropics poleward. Examples include the Gulf Stream, theAgulhas Current, and the Kuroshio.
How ocean currents are generated?
Ocean currents can be generated by the wind, density differences in water masses caused by temperature and salinity variations, gravity, and events such as earthquakes. Currents are cohesive streams of seawater that circulate through the ocean.
How does heat transfer causes ocean currents?
Ocean currents result from two processes - the action of the wind on the surface of the water, and from variation in water temperature that causes movement- a process known as convection. Convection occurs because the oceanic waters heat up becoming less dense.
How energy is transferred in the ocean?
The transfer of heat energy within the atmosphere, hydrosphere, and the Earth's surface and interior occurs as a result of radiation, convection, and conduction.Ocean currents play a significant role in transferring this heat toward the poles.
What causes the waves and tides?
Waves caused by underwater disturbances such as earthquakes, landslides, or volcanic eruptions are called tsunamis. These waves are typically tens to hundreds of kilometres long. The gravitational pull of the sun and moon on the earth causes the tides which are actually tidal waves.
How do geysers form?
As the water boils, the resulting pressure forces a superheated column of steam and water to the surface through the geyser's internal plumbing. The formation of geysers specifically requires the combination of three geologic conditions that are usually found in volcanic terrainSee also:
