TOPIC: OCEAN CURRENTS

*To be read along with class notes and relevant diagrams

Currents​of the Atlantic​Ocean

Major currents of the Atlantic Ocean are:
North and South Equatorial Current
●​ To the north and south of the equator, there are two westward moving
currents-the North Equatorial Current and the South Equatorial Current.
●​ Due to the rotation of the Earth, these currents move almost due west
along the equator.

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●​ The North Equatorial Current moves northwards due to the presence of

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the South American continent and the Coriolis force, and takes the
north-west direction. It enters the Gulf of Mexico to form the Gulf
Stream.

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●​ The South Equatorial Current originates from the western coast of
Africa, from where it moves towards South America.
●​ The east coast of Brazil obstructs the South Equatorial Current which
then bifurcates into two branches.
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●​ The northward branch merges with the North Equatorial Current, while
the second branch flows along the east coast of Brazil and is known as
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the Brazilian Current.

●​ The North Equatorial Current and the South Equatorial Current are
warm currents.
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Gulf Stream
●​ The Gulf Stream is one of the largest warm currents. It originates from
the Gulf of Mexico (about 20° N) and moves in a north-easterly direction
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along the eastern coast of North America.

●​ The average speed is about 33 km per day and its average width is
about 70 km.
●​ Under the impact of the Westerlies, this warm current reaches the
western coast of Europe (about 70° N latitude).
●​ The general direction of flow of the Gulf Stream, north of 30° N latitude,
is northward. Near Newfoundland, its water mixes with the cold water of
the Labrador Current, which forms a very dense fog.
●​ The foggy conditions around Newfoundland hamper the navigation of
ships.
●​ From here, the Gulf Stream moves north eastwards. This current
gradually widens and its speed decreases. It becomes a prominent, slow
moving current known as the North Atlantic Drift.
●​ Near Western Europe, it splits into two parts. One part moves
northwards, past UK and Norway, while the other part is deflected
southwards as the cold Canary Current.
●​ The warm water of the Gulf Stream modifies the weather conditions off
the eastern coast of North America and the western coast of Europe. On

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the western coast of Europe, the seaports remain open even in the

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severe winter season due to the warm water of the Gulf Stream.
Labrador Current
●​ The cold Labrador Current of the North Atlantic Ocean, has its origin in
the Arctic Ocean. This current flows from north to south between
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Greenland and the Baffin islands.
●​ The Labrador Current merges with the Gulf Stream near Newfoundland.
This helps in the growth of plankton- a feed for fish. Thus the Grand
Banks near Newfoundland have become the ideal fishing ground in the
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world.
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●​ The average speed of the Labrador Current is about 25 km per day. This
current brings huge icebergs with it from the Arctic Ocean.
Canary Current
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●​ The Canary Current is a cold current and flows along the western coast
of Spain and Portugal and the north-west coast of North Africa. The
average speed of this current is about 45 km per day.
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●​ The relative coolness of the Canary Current reduces the relative

humidity and thus causes scanty rainfall in the greater parts of the
Sahara Desert.
Brazil Current
●​ The Brazil Current is a warm current and flows southward along the east
coast of South America (about 40° S latitude).
●​ The average speed of the Brazil Current is about 30 km per day.
●​ From 40° S, it is deflected eastwards due to the Earth's rotation and
flows in easterly direction.
●​ It modifies the weather conditions along the eastern coasts of Brazil and
Argentina.
Falkland Current
●​ The cold waters of the Antarctic Sea flow as the Falkland Current from
south to north along the eastern coast of South America up to Argentina.
●​ The Falkland Current brings huge icebergs from the Antarctic region to
the South American coast.
Benguela Current
●​ The Benguela Current is a cold current which originates in the Antarctic
region and flows along the coast of south-west Africa.

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●​ The Benguela Current helps in reducing the relative humidity of the

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eastward moving warm and moist air masses.
●​ The Kalahari Desert is largely formed under the influence of this current.
Further northwards, the Benguela Current merges with the South
Equatorial Current.
South Atlantic Drift K
●​ The eastward continuation of the Brazil Current is called the South
Atlantic Drift or the West Wind Drift.
●​ It develops at about 40° S latitude due to the impact of the Westerlies.
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●​ The eastward movement is due to the Earth's rotation.
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Currents​of the Pacific Ocean

Major currents of the Pacific Ocean are:
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North Equatorial Current

●​ The North Equatorial Current is a warm current which originates off the
western coast of Mexico and flows in the westerly direction.
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●​ It runs parallel to the equator and reaches the islands of the Philippines
after covering a distance of about 12,000 km.
●​ Near the Philippines, under the impact of Coriolis force, it turns
northwards. One branch of the North Equatorial Current flows northward
to join the Kuroshio Current, while the southern branch turns eastwards
to form the Counter Equatorial Current.
South Equatorial Current
●​ The South Equatorial Current is a warm current which originates due to
the influence of South-east Trade winds and flows from east to west.
●​ It bifurcates into northern and southern branches near New Guinea.
●​ The northern branch turns eastward and joins the Counter Equatorial
Current, while the southern branch flows along the north-eastern coast
of Australia.
Kuroshio Current
●​ Kuroshio Current is an important warm current, which develops partly
due to the Coriolis force and partly due to the obstruction by the

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Philippines in the flow of the North Equatorial Current.

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●​ The average velocity is about 30 km per day and the average surface
temperature is about 20°C.
●​ This current keeps the eastern coast of Japan warm even in the coldest
month (January), when it is snowing heavily in Honshu and Hokkaido.
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●​ A branch of Kuroshio Current enters the Sea of Japan as Tsushima
Current and keeps the western coast of Japan comparatively warm.
●​ Around 35° N, the Kuroshio current comes under the impact of the
Westerlies and flows in the north-east direction to reach the western
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coast of North America.
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●​ Further northwards, it is known as the Aleutian Current.

Kurile or Oyashio Current
●​ The Kurile or Oyashio Current is a cold current which originates from the
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Bering Strait and moves southwards along the coast of the Kamchatka
peninsula to touch the island of Kurile.
●​ It carries with it the cold water and icebergs from the Arctic Ocean to the
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coast of eastern Russia and Japan.

●​ Near 50° N latitude, it is bifurcated into two branches. One of them
merges with Kuroshio Current and creates dense fog which is
hazardous to navigation, but ideal for abundant growth of plankton. Thus
the north-eastern coast of the Japanese islands is an important fishing
ground in the world.
●​ The second branch moves up to the Japanese coast. The Oyashio
Current is comparable to the Labrador Current of the North Atlantic
Ocean.
California Current
●​ The California Currents is a cold current which flows southwards along
the Pacific coastline of USA, and is comparable to the Canary Current of
the Atlantic Ocean in most of its characteristics.
●​ After reaching the Mexican coast, it turns westward and merges with the
North Equatorial Current.
Peru Current
●​ The Peru Current is a cold current, also known as the Humboldt Current,
which flows along the western coast of South America.
●​ It flows from south to north along the coast of Peru and is caused by the

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northward deflection of the West Wind Drift.

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●​ It affects the coastal climate of Chile and Peru.
East Australian Current
●​ The East Australian Current is a warm current which is the southern
branch of the South Equatorial Current, which flows from north to south
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along the eastern coast of Australia.
●​ New Zealand is surrounded by this current.
●​ It raises the temperature along the east Australian and the New Zealand
coasts for considerable distance southwards.
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West Wind Drift
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●​ It is a strong, cold current, flowing from between Tasmania and the

South American coast.
●​ It flows under the influence of the Westerlies and is largely confined
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between 40° S and 50° S latitudes.

●​ This current becomes very strong due to the large volume of water and
high velocity winds (Roaring Forties).
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●​ One of its branches enters the Atlantic Ocean through Cape Horn, and
the other branch turns northwards and joins the Peru Current.

Currents​of the Indian Ocean

The ocean currents of the Indian Ocean are largely controlled and modified
by the landmasses and the Monsoon winds. The ocean currents of the
North Indian Ocean flow under the influence of the north-east and the
south-west Monsoon winds. Thus the ocean currents change the direction
 of flow twice a year. The currents in the southern Indian Ocean follow the
general pattern of other oceans and are not affected by the seasonal
changes in the direction of Monsoon winds.
Major currents of the Indian Ocean are:
North-east Monsoon Current
●​ In the winter season, the north-east Monsoon winds blow from land to
ocean and from the northeast to the south-west in the Northern
Hemisphere.
●​ Under the influence of these winds, the ocean current also flows from
the north-east to the southwest.

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South-west Monsoon Current

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●​ There is a complete reversal in the direction of Monsoon winds during
the summer season and they blow from the south-west to the north-east
in the Northern Hemisphere. This also reverses the direction of the
ocean current. Now the direction of the ocean current also changes from
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the south-west to the northeast.
●​ Two branches of the main current move in the Arabian Sea and the Bay
of Bengal.
South Equatorial Current
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●​ The warm South Equatorial Current flows from east to west between 10°
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S and 15° S latitudes from the western coast of Australia to the coast of
Africa.
●​ After being obstructed by the Madagascar Island, this current is divided
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into many branches. • One major branch flows towards the south as the
Agulhas Current.
Agulhas Current
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●​ The Agulhas Current is a warm current which is a branch of the South

Equatorial Current which flows along the eastern coast of South Africa
●​ Around 35° S latitude, it comes under the influence of the Westerlies and
flows towards the east.
Mozambique Current
●​ The Mozambique Current is a warm current which is the northern branch
of the South Equatorial Current which enters the Mozambique Channel
around 10° S latitude.
●​ Moving southwards between Mozambique and Madagascar, it joins the
Agulhas Current around 30°S latitude.
West Wind Drift
●​ The West Australian Current is a cold current in the southern part of the
Indian Ocean and moves from west to east around 40° S latitude.
●​ The West Wind Drift develops under the influence of the Westerlies
(Roaring Forties).
West Australian Current
●​ The West Australian Current is a cold current which flows along the
western coast of Australia.

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●​ This current turns towards west and north-west near the Tropic of

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Capricorn and finally merges with the South Equatorial Current.
●​ The second branch flows to the south of Australia and finally merges
with the West Wind Drift in the Pacific Ocean.

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