Question.
Explaining the factors affecting ocean currents, give an account of the currents of the Pacific Ocean. ( UPPSC 2020)
Answer.
When the water of the sea flows in the same direction as the water flow of rivers, it is called ocean current. There are two types of ocean currents according to depth:
- Surface current
- Deep-sea current
Deep ocean currents are largely unaffected by external factors, but surface ocean currents are influenced by many factors.
Following are the factors affecting ocean currents:
- Wind Direction
- Coriolis force
- Temperature
- Salinity
- Coastal terrain
Wind Direction:
- The direction of the prevailing winds over the sea affects both the direction and speed of the flow of ocean currents to a great extent.
- Permanent winds such as trade winds, westerly winds, and polar winds play a major role in the direction of ocean currents.
- For example, Kuroshio in the Pacific Ocean and the Gulf Stream move in a northeasterly direction under the influence of westerly winds.
Coriolis force:
- The Coriolis force moves currents clockwise in the Northern Hemisphere and in counterclockwise directions in the Southern Hemisphere.
- For example, due to the Coriolis force, the Gulf current in the Atlantic Ocean is deflected further to the right.
Temperature:
- As we know that the insolation is higher in the equatorial region as compared to the polar region and we also know that the water expands when it is heated, due to which the water at the equator is about 8 cm higher than in the middle latitudes And this causes the current to move towards the poles from the equatorial region.
Salinity:
- High salinity water is denser and denser water sinks while less dense water comes to the surface.
Coastal terrain:
- Coastal landmass obstructs the current movement. For example, the coast of Brazil divides the Atlantic South Equatorial Current into two parts.
Pacific Ocean Currents:
Following are the currents of the Pacific Ocean:
Warm ocean currents of the Pacific Ocean:
- North equatorial current
- Kuroshio
- Alaska
- South equatorial current
- Eastern Australia Current
Cold Currents:
- California current
- Osashio
- Peru or Humboldt Stream
- Antarctica current
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