IAS: Oceanography Currents

Ocean Currents

Atlantic Ocean

Warm Currents

  1. North Equatorial Current: It is formed between equator and 10° N latitude. It has two branches

    1. Antilles, is diverted northwards and flows to the east of West Indies island and helps in the formation of Sargasso sea (which is between 20° 40° N. Latitude). Sargasso seaiia& maximum salinity in Atlantic and mean temperature is 28° C

    2. Caribbean current enters Gulf of Mexico and becomes Gulf Stream.

  2. South Equatorial Current: It is 20° S latitude from the equator. It basically originated under the stress of the trade wind.

  3. Counter Equatorial Current: It flows from west to east, also called Guinea stream or Compensation current.

  4. Gulf Stream: Originates in Gulf of Mexico, around 20° N latitude. It has three branches

    1. Florida Current, the average temp, of water at its surface is 24° C or 75° F, while salinity is 36%. At 30° N latitude, its temperature falls upto 6.5° C or 43.7° F

    2. Gulf Stream, was first discovered by PoncedeLeon in 1513. The Florida Current after having water of Antilles current is known as Gulf Stream beyond Cape Hatteras (Near Washington)

    3. North Atlantic Drift or Current, 45° N latitude and 45° W longitude, the Gulf Stream is divided into many branches. All the branches are collectively called North Atlantic Drift/Current. It has two branches:

      1. Northern branch it has two branches, one goes towards Norwegian sea and second one goes towards South Iceland and here it is called Irminger Current

      2. Eastern branch one branch enters Mediterranean sea near Gibraltar and second branch is called Rennell Gmren near Bay of Biscay.

  5. After Sargasso sea, the temperature is reduced to 410° C and here, a round Gulf of St. Lawrance near Halifax, the Gulf Stream is called ‘Cold Wall’ It loses its original characteristic near 40° N latitude because it meets the cold Labrador current. 5. Brazilian Current: Flows up to 40° S latitude and merges with Gold Falkland Current. Sargasso Sea has 3 currents:

    1. North Equatorial Current

    2. Canary Current

    3. Gulf Stream.

    Water is very calm and motionless; found between 20° N − 40° N latitude. Between 35° -75° W longitude. Highest salinity is 37%.

Cold Currents

  1. Labrador Current: Originates in Baffin Bay and Davis Strait and merges with Grand Bank (Gulf Stream) around 50° W longitude. Big icebergs are found near New Foundland and Grand Bank.

  2. Canary Current: Flows along the western coast of North Africa between Maderia and Cape Verde.

  3. Falkland Current: 30° S latitude.

  4. South Atlantic Drift: Is the Eastward continuation of Brazilian Current 400 S latitude.

  5. Benguela Current: Flows from South to north along the western coast of Africa. Later merges with south Equatorial current.

Pacific Ocean

Warm Currents

  1. North Equatorial Current: Originates of the western Coast of Mexico and flows in western lie direction and reaches the Philippine coast. This originates because of Californian Current and NE. Monsoon. It is joined by Kuroshio Current near Taiwan and counter equatorial current near Japan.

  2. South Equatorial Current: Originates due to SouthEast Trade winds and. Flow from east to west, bifurcated near New Guinea.

  3. Counter Equatorial Current: It extends upto Panama Bay. Its average temp, is 27.5° C and the salinity is 34.5%.

  4. Kuroshio System: Startefrom Taiwan from the Bering Strait and has five currents

    1. Kuroshio Current 30° N latitude; from Taiwan to Raiku Ridge.

    2. Kuroshio Extension 42° N latitude and Oyashio current (a cold current).

    3. North Pacific Drift up to Aleutian Current and becomes a part of it.

    4. Tsushima current; between Japanese sea and western coast of Japan. It is warm and enters Japan sea by the name of Tsushima Current.

    5. Counter Kuroshio Current between Hawaiian island and American coast.

  5. East Australian Current: 40° S; is warm.

  6. Counter or El Nino Current: 3° -30° S; along Peruvian Coast.

Cold Currents

  1. California Current: Near Mexico.

  2. Peru Current: Is also called ‘Hobalt’ or ‘Humboldt’ Current. Annual temperature is 14° 17° C.

  3. West Wind Drift: Also called roaring 40s between Tasmania and South American Coast. 40° 50° S.

  4. Oyashio Current: Known as Kurile Cold current. From Berring Strait to Arctic sea; divides into two parts at 50° N latitude one merges with Aleutian and Kuroshio Current and second moves upto the Japanese coast.

Indian Ocean

The currents flowing in the Indian Ocean change their flow direction twice a year due to North east and South West Monsoon winds.

Warm Currents

  1. North East Monsoon Current: 5° N latitude; originates in the Bay of Bengal reaches to Arabian Sea.

  2. Indian Counter Current: 2° -8° S latitude: Mainly concentrated to Zanzibar to Sumatra.

  3. South West Monsoon Current.

  4. Indian Equatorial Current: 10° -15° S; from Australian to African Coast and is obstructed by Madagascar. One major branch flows southwards, known as ‘Agulhas Current’ which is warm.

  5. Mozambique Current: It is a part of Indian equatorial; joins Agulhas Current near 30° S latitude.

  6. West Wind Drift: 40° N latitude; 110° East; known as ‘Roaring 40s’ one branch flows as west Australian cold current along the Western Coast of Australia and near the Tropic of Capricorn turns towards the left.

Discussions & Questions

  • Know the ocean current flow pattern (all the five grid seperately). from where the ocuuents originate and till where they flow ?.. how they mix with cold currents and everything accurately. ( - on ))

    1 Answer

    For oceanography waves and currents visit the video lecture - https://www.youtube.com/watch?v=0Ye5CYtAC3A

    - on