Pacific Ocean Currents
Pacific Ocean Currents includes various cold and warm current which moves clockwise circulation in
- North Equatorial Current (Warm)
- South Equatorial Current (Warm)
- Counter Equatorial Current (Warm)
- Kuroshio System (Warm)
- North Pacific Drift (Warm)
- Oyashio Current (Cold)
- California Current (Cold)
- Peruvian or Humboldt Current (Cold)
- East Australia Current (Warm)
Pacific Ocean Currents
- These start on the west coast of Central America and under the influence of the prevailing trade winds traverse east to west.
- Due to larger expanse of the Pacific ocean and
absenceof any obstructing landmass, the volume of water in the Equatorial Pacific currents is much larger than that of the Equatorial Atlantic currents.
Equatorial Counter Current
- Due to the convergence of a large mass of water from the equatorial currents in the western Pacific near Indonesia and Australia, there is piling up water due to which the sea level rises by a few centimetres.
- This creates an equatorial Countercurrent between the North Pacific and South Pacific Current.
- This current flows from West to East.
Since all the above currents originate and flow near the equator, they are warm currents.
- The North Equatorial Current under the influence of the North-east Tradewinds flows off the coasts of Philippines and Formosa as the Kuroshio current in the East China Sea.
- This is also known as Kuru Siwo or Japan Current.
- Most of it lies in the subtropical high-pressure belt and is under the influence of the westerlies.
- Since it carries the equatorial waters, it is a Warm current.
North Pacific Drift
- The warm waters of the Kuroshio current are carried polewards as the North Pacific Drift.
- This current keeps the ports of Alaska ice-free in winter.
- This current splits into two: The Alaskan current and the California Current.
- This results from the northward diversion of the North Pacific Drift.
- This current is relatively warm compared to the surrounding waters of the region.
- It flows along the coast of British Columbia and Alaskan Panhandle.
- The south branch of the North Pacific Drift flows as the cold Californian current along the coast of Western U.S.A and joins the North Equatorial Current.
- This completes the clockwise circulation of the currents in the Northern Pacific.
- This cold current is one of the reasons for the dry conditions along the West coast of the USA and the state of California.
- Also known as Oya Siwo, Okhotsk or the Kurile current is a cold subarctic current flowing from the Bering Strait.
- It flows southwards in a counter-clockwise direction and joins the Kuroshio current off the Japanese island of Hokkaido.
- Since this region forms the convergence of warm and cold water currents, it has ecological and economic significance to Japan.
North Pacific Gyres
- The Northen Pacific Gyres include the North Pacific Subtropical Gyre and North Pacific Subpolar Gyre.
- The North Pacific Subtropical Gyre is one of the largest ecosystems on the Earth, with phytoplankton and marine organisms.
- It is surrounded by:
- Kurushio current on the West,
- North Pacific Drift on the North,
- California current on the East and
- North Equatorial Current on the South.
- The North Pacific Subpolar Gyre is composed of the north-flowing Alaskan current and Aleutian current also known as Sub-arctic current and the south-flowing Oyoshio current.
- The North Pacific Drift separates the North Pacific Subtropical and Subpolar Gyres.
East Australian Current
- The South Equatorial current flows from east to west in the Southern Hemisphere and on reaching the landmass of Australia and under the influence of South-East, Tradewinds flows southwards as the East Australian Current.
- As this carries the Equatorial waters into temperate regions, it is a warm current.
South Pacific Current
- The East Australian current turns eastwards towards New Zealand under the influence of Westerlies in the Tasman Sea.
- It then merges with the West Wind Drift or the Antarctic Circumpolar Current as the South Pacific Current.
- The South Pacific Current is obstructed by the tip of Southern Chile and flows northwards as the Peruvian current.
- This is also known as the Humboldt Current.
- Since it brings waters of the West wind Drift it is a cold current.
- The cold water chills any winds that blow on-shore so that Chilean and Peruvian coast are practically rainless.
- The Peruvian current eventually links up with the South Equatorial Current completing the anti-clockwise circulation in the South Pacific Ocean.