What is Ocean current ? Definition,types and causes.

Ocean Currents

Ocean current

The movement of oceanic water in the ocean in a particular direction is called ocean current.

TYPES OF OCEAN CURRENT

There are two types of ocean current.They are follows:

Warm and cold ocean current

1. Warm current-These are the currents which flows from the low latitudes(tropic zones) to the high latitudes(temperate and sub-polar zones).
2. Cold currents-These are the currents which flows from the high latitudes towards the low latitudes.

FACTS TO BE KNOWN

Ocean current

• The forward of the oceanic water in the direction of the movement of the wind is called drift.
• The drift which moves at a speed of about 3 km to 8 km in a particular direction is called current.
• The movement of huge mass of water on the land surface with a velocity of about 6 km to 10 km i called stream.

CAUSE OF OCEAN CURRENT 

Causes of ocean current

The ocean current is caused due to some factors.These are as follows:

ON THE BASIS OF TEMPERATURE

• The temperature of water decreases from the equator to the poles and from the surface towards the bottom.
• As a result the density of water in equator is less dense than polar region.
• By these way the warmer water flows towards the pole and the cooler water towards the  equator.

ON THE BASIS OF SALINITY OF OCEAN WATER

• Two water bodies at same temperature may vary on salinity  of the water.The water with greater salinity  has greater density than the water with lower salinity.
• Thus, the water with more salinity tends to sink downwards and the lesser saline water takes its place,this causes the circulation of the water.
• This current takes place in from the lesser to the higher saline water.

ON THE BASIS OF EVAPORATION OF OCEAN SURFACE

• The level of ocean water is higher in the areas of the low evaporation and high rainfall than the areas of high evaporation and low rainfall.
• As a result  the ocean current takes place from the high level of ocean water to the low level of ocean water.
• These current generally occur in the equatorial region due to relatively  high rainfall and low evaporation than the other region.

ON THE BASIS OF DIRECTION OF PREVAILING WINDS

• Due to the friction of the wind with the water surface of the ocean  it provides a movement in the water.
• Most of the ocean water follow the movement of the prevailing wind.

ON THE BASIS OF ROTATION OF THE EARTH

• The phenomena of Coriolis effect caused by the rotation of the earth changes the general direction of the ocean current.
• The rotational  also causes the movement of ocean water near the equator in opposite direction.