Major ocean currents of the world Upsc

In every ocean, there is the circulation of ocean water from the Equator to the pole and from the pole to the equator. The warm currents from the equator flow over the surface of the ocean towards the pole and sink to the bottom of the ocean floor in the higher latitudes due to high density and flow towards the equator to complete the circulation. This large-scale circulation is known as gyre.

The gyre circulates clockwise in the northern hemisphere and anti-clockwise in the southern hemisphere.

Major ocean currents of the world

Ocean currents of the Pacific Ocean

1.1. North Equatorial Current

The north equatorial current originates from Revilla Gigedo Island west of Mexico and flows toward the Philippines Island covering a distance of about 12,000 km from east-west. It is a warm current. It derives from its water from the Californian current and the Southeast Monsoon drift which flows north along the Mexican coast.

The volume of water increases from east to west as many small currents join it from the right. It gets divided into two and the northern branch joins the Kuroshio Current and the southern branch abruptly turns and forms the Pacific counter current.

1.2 South Equatorial Current

South equatorial current originated due to the action of the trade winds from east to west. It is a warm current. It extends for about 13,600km from east to west. It is stronger than the North equatorial current. It is further divided into many branches due to the presence of many islands and uneven surface topography.

1.3 Kuroshio Current (Black Tide)

It is a warm ocean current flowing in north-easterly direction up to 30° N latitude and it carries warm
water off the Formosa coast. It flows towards the north and meets the Oyashio cold current off the Kuril Islands. It is also called as Japan current.

1.4 Oyashio Current (Parental Tide)

It originates from the Bering Strait and flows towards the south carrying cold water. It is a cold current. It meets with Kuroshio’s warm current and Aleutian current.

1.5 Californian Current

Californian current is flowing towards the south along the west coast of the U.S.A. between 48° N and 23° N latitudes. It is a cold current that exhibits a great amount of upwelled water. When it enters the region of Trade winds, it is deflected to the right and joins the equatorial current.

1.6 Peru Current

Peru Current is perhaps the best-studied ocean current in the Pacific Ocean. Alexander Von Humboldt in 1802 noted the details of the Peru Current. Hence, it is also known as Humboldt Current. It is a cold current. It is flowing north along the west coast of South America carrying cold water from northerly deflection of the Sub-Antarctica water moving at 40° S.

1.7 El Nino or Countercurrent

It is a warm counter ocean current of the Pacific equatorial waters flowing southward at 400 m depth
to a distance of about 180 km.

1.8 West Wind Drift

It is an easterly moving drift in the Pacific Ocean extending from Tasmania to the South American coast. It is a cold current. The speed of the drift is greater under the influence of Roaring Forties. It splits into two branches and one moves south around the Cape Horn into the Atlantic Ocean and the Other one moves northward along the Peruvian coast due to deflection and joins the Peru Current.

2. Currents of the Atlantic Ocean

2.1 North Equatorial current

North equatorial current is flowing from east to west. It is a warm current. It is situated between 5° – 20°
N latitudes. After leaving the west coast of Africa, it attains its main characteristics. When it reaches the
east coast of South America, it splits into two branches one branch called Antilles Current moves
along the coast of the West Indies, and the other branch is diverted into the Caribbean Sea.

2.2 South Equatorial current

It is flowing south of the equator within 0° – 12° S latitude in between the coast of Africa and South America. It
is a warm current. It is a northern continuation of the Benguela current. It is stronger than the North equatorial
ocean current. It is caused by the action of Trade winds.

2.3 Gulf Stream

The Gulf Stream starts from the Gulf of Mexico and carries warm waters into the colder latitudes. It is a warm current. It bends with the coastline up to the 40th parallel after which the direction is almost to the east, due to the force and the direction of the westerlies and the deflective force of the earth. It joins the Labrador Cold Current near New Found land, Canada after passing through the strait of Florida. The Gulf Stream was discovered by Ponce de Leon in 1513.

2.4 Canaries Current

The ocean current flowing along the Western coast of North Africa between Maderia and Cape Verde is known as the Canaries Current. It is a cold current. It is flowing towards the south and merging with the North equatorial current.

2.5 Labrador Current

In the North Atlantic, a cold current flows from the Baffin Bay and Davis Strait towards the south. It brings cold waters from the polar zone and moves along the coast of green land.

2.6 Benguela Current

It is a cold current flowing northward along the western coast of Africa known as the Benguela current. It carries cold waters from sub-Antarctica surface water and mixes with the south equatorial current.

3. Currents of the Indian Ocean

The south Indian gyre is formed by the south equatorial current, Madagascar current west wind drift, and west Australian current. To the north of the equator, the currents in the Arabian Sea and Bay of Bengal flow in the clockwise direction as southwest monsoon drift and in the anti-clockwise direction as northeast monsoon drift due to the influence of monsoon winds.

The Antarctic circumpolar current flows between 40 to 60° S latitude. It flows from west to east influenced by the westerly and circles around the entire Antarctica. There is a counter-westward current within this circumpolar current.

4. Currents of the Southern Ocean

The southern ocean surrounds the continent of Antarctica. The large oceans, the Pacific, the Atlantic, and the
The Indian Ocean merges into this circumglobal zone of water to their south. The movement of water in the southern
ocean is in one sense a relatively simple, generally west-east circumpolar drift caused under the influence
of northwesterly winds.

This general flow sends offshoots to the three major oceans to its north. The Peru or Humboldt Current in the Pacific Ocean, the Falkland Current and the Benguela Current in the Atlantic Ocean, and the West Australian Current in the Indian Ocean receive a part of their cold waters from the Southern Ocean.

Besides the surface currents, there is also a very complex system of sub-surface currents between the southern ocean and the oceans to its north.

Generally, the water moves from this ocean towards the equator on the surface and at great depths but at remediate depth, there is a movement of water from the equatorial areas towards the southern ocean.