IAS (Admin.) IAS Mains GS Paper 1 (Geography, Art & Culture, and History): Questions 1 of 147

Edit

Appeared in Year: 2015

Describe in Detail

Essay▾

Explain the factors responsible for the origin of ocean currents. How do they influence regional climates, fishing and navigation? (Comparing good and average answer)

Explanation

Good Answer

Factors responsible for the origin of ocean currents:

  • Planetary winds: The winds cause friction on the water surface and drive the ocean water along them.
  • Temperature/Density: With high temperature, the evaporation rate is higher which lowers the level of water in relation to other water bodies. Eg: The Mediterranean Sea, gets heated up, loses water and water flows in from the Atlantic via the Gibraltar Strait. Also denser water sinks causing deep ocean currents.
  • Coastal topography. Topography of the coasts and shallows direct the currents to a specific place.
  • Coriolis Force: It is the force that is created due to the rotation of earth. In the northern Hemisphere the Coriolis force shifts a moving ocean current to the right while it shifts an ocean current to the left in the southern Hemisphere. The shift is roughly 45˚ to the direction of the push from the wind.
The Origin of Ocean Currents

Effects of currents on:

Regional climates:

  • Oceans currents are one method of transfer of energy on earth. They transfer the heat around the world.
  • Eg: Southern UK, under the influence of warm Gulf stream has a relatively warmer climate when compared to other places of the same latitude.
  • The Californian Gulf stays relatively cold due to the presence of the cold ‘California Current’ .

Fisheries:

  • The major fishing grounds of the world are at the places where warm and cold currents meet. Eg: The Grand banks, off Newfoundland is the place where warm Gulf Stream and cold Labrador Current meet.
  • Currents take along with them eggs/fry (baby fish) to different places from their place of birth for spawning or better growth.

Navigation:

  • Knowing the currents of an area is useful to save fuel and time. Going with the current increases speed and going against it decreases the speed.
  • Also warm ocean currents allow ports to open all the year in higher latitudes. Eg: The port of Murmansk would have been closed in winters had it not been for the warm Gulf stream that flows along the Norwegian coast.
Effects of Ocean Currents

Average Answer

Factors responsible for the origin of ocean currents:

  • Planetary winds: The winds cause friction on the water surface and drive the ocean water along them.
  • Temperature/Density: With high temperature, the evaporation rate is higher which lowers the level of water in relation to other water bodies. Eg: The Mediterranean Sea, gets heated up, loses water and water flows in from the Atlantic via the Gibraltar Strait. Also denser water sinks causing deep ocean currents.
  • Coastal topography. Topography of the coasts and shallows direct the currents to a specific place.
The Effect of Currents

Effects of currents on:

Regional climates: Oceans currents are one method of transfer of energy on earth. They transfer the heat around the world. Eg: Southern UK under the influence of warm Gulf stream has a relatively warmer climate when compared to other places of the same latitude.

Fisheries: The major fishing grounds of the world are at places where warm and cold currents meet. Eg: The Grand banks off Newfoundland is the place where warm Gulf stream and cold Labrador current meet.

Navigation: Knowing the currents of an area is useful to save fuel and time. Going with the current increases speed and going against it decreases the speed. Also warm ocean currents allow ports to open all the year in higher latitudes. Eg: The port of Murmansk would have been closed in winters had it not been for the warm Gulf stream that flows along the Norwegian coast.