Question.
Which are the main oceanic currents of the world? Compare and contrast the climatic impacts of North Atlantic Drift and Labrador current on coastal areas. ( 25 Marks, 66th BPSC geography)
Answer.
Ocean water is not static, it is dynamic. Ocean water moves both vertically and horizontally.
- The vertical movement of seawater includes tides, upwelling [the rising of the ocean water], and the sinking of heavy water.
- Horizontal movements of ocean water include waves and ocean currents.
- Ocean current is the horizontal movement of seawater in a particular direction and it flows like a river.
There are also many types of ocean currents.
Ocean currents can be classified into two types on the basis of depth:
- Surface ocean currents
- Deep ocean currents
Surface ocean currents flow in the upper 400 m of the ocean and they account for 10% of ocean water.
Deepwater currents make up 90% of ocean water that normally runs 400 meters below seawater.
On the basis of temperature, ocean current can be classified into two types:
Cold currents
- Cold currents bring cold water to warm areas.
- Cold currents are generally found on the west coast of continents in both the hemispheres in the low and mid-latitudes.
- and are found on the east coast in high latitudes in the Northern Hemisphere.
Warm Currents:
- Warm currents bring warm water to cold regions.
- Warm currents are generally found along the east coast of continents in low and mid-latitudes in both hemispheres and they are found along the west coast in high latitudes in the northern hemisphere.
The following are the major ocean currents of the world:
Major ocean currents are influenced by prevailing winds and the Coriolis force.
The main ocean currents of the Pacific ocean are:
- Alaska Current[ Warm current]
- California current [ cold current]
- Humboldt or Peru current[ Cold current]
- Oyashio Current [Cold current]
- Kuroshio current[ Warm current]
The main ocean currents of the Atlantic Ocean are:
- Gulf Stream [ Warm current]
- Labrador current [ Cold current]
- North Atlantic Drift current [Warm current]
- Canaries Current [Cold current]
- Brazilian current [ Warm current]
- Falkland Current [ Cold current]
- Benguela Current [Cold]
The main ocean currents of the Indian ocean:
- Agulhas current; warm current]
- West Australian current[cold current]
Comparison of the climatic effects of the North Atlantic Current and the Labrador Current on Coastal Areas:
Effect of Labrador Current on Climate:
- The Labrador Current is a surface ocean current as well as a cold current.
- It flows into the Atlantic Ocean off the east coast of Canada.
- It brings less saltwater [30 to 34 parts per 1000] and icebergs to the south.
- The Titanic ship sank in the Labrador Current in 1912.
- The Labrador Current, along the eastern coast of Canada, makes summers cold and winters extremely cold.
North Atlantic Flow:
- The Gulf Current [warm ocean current] splits into two parts:
- North Atlantic current [warm ocean current]
- canary stream [cold stream]
- The North Atlantic Drift flows west of Britain and northern Europe.
- Despite being located in the high latitudes of North-Western Europe and Britain, the ports there do not freeze in ice and are accessible for trade for twelve months. All this is due to the North Atlantic current as this current brings with it warm waters in the region.
- Both westerly winds and North Atlantic currents make northwestern Europe a warm climate zone on cold days.
- North Atlantic current brings saline water to the northwestern part of Europe.
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