Ocean Currents
Ocean Currents
Ocean currents are the regular movements of water in the
oceans. They move in a circular pattern around the oceans.
Based on temperature and depth, ocean currents may be
divided into the following divisions:
Factors which affect ocean currents:
● Temperature: Temperature affects the origin and
nature of ocean currents. As equatorial and tropical
regions are warm, the oceans lying near the
Equator and the tropics are warmer than the
oceans lying near the Polar Regions. Thus, the
ocean currents from warm equatorial regions move
towards the Polar Regions as warm currents.
Similarly, the cold currents move from the Polar
Regions to the equatorial regions as cold currents.
● Level of Salinity: Oceans with a higher level of
salinity are denser than oceans with lower levels of
salinity. Generally, the ocean currents are
generated from areas of less salinity to areas of
high salinity. Because the Mediterranean Sea is
more saline than the Atlantic Ocean, most ocean
currents flow from the Atlantic Ocean to the
Mediterranean Sea.
● Rotation of the Earth: The Earth rotates from west to
east. The speed of rotation of the Earth is maximum
at the Equator. All the moving bodies move in a
clockwise direction in the Northern Hemisphere and in
an anti-clockwise in the Southern Hemisphere. This is
also known as the Coriolis Effect.
● Planetary Winds: Winds affect the ocean currents.
The trade winds blow between the Equator and the
Tropics. These winds thus move the equatorial water
towards the poles. For example, the Southeast Trade
Winds drift the equatorial current to the eastern coast
of Australia as the warm East Australian Current.
● Landforms: A landform may influence the ocean
currents. For example, the shape of various
landmasses may obstruct the flow of water and
influence its movement. For example, the South
Equatorial Current gets deflected towards the
Northern Hemisphere.
Add Learning Aid: All About Global Winds
The circulation pattern of the ocean
currents is influenced by the Earth’s
atmospheric circulation pattern. At higher
latitudes, the wind flow is cyclonic. Thus,
the oceanic currents move in a cyclonic
pattern. Similarly, in middle latitudes, air
circulation is mainly anti-cyclonic. The
currents thus move in an anticyclonic
pattern.
Add Learning Aid: How do ocean currents work?
Major Ocean Currents
Add Learning Aid:Perpetual Ocean
Effects of Ocean Currents
Affect Temperatures: Currents influence the
climatic conditions of the regions in which they
blow. The warm equatorial currents raise the
temperature of the region in which they blow.
Similarly, the cold currents lower the
temperature of the places where they blow. For
example, British Isles would have been
extremely cold without the warm North Atlantic
Drift. The hot climate of Peru is cooled by the
cold Peru Current.
Affect Rainfall: The winds blowing over warm
currents pick up and carry moisture and bring
rainfall. For example, the North Atlantic Drift
brings rainfall in some areas located along the
western coasts of Europe. On the contrary, cold
currents do not bring rainfall and make the
region cooler and drier. The Kalahari Desert
hardly experiences rainfall because of the cold
Benguela Current.
Fog: The meeting of the warm and cool currents
results in the creation of fog. For example, the
Japanese coast
Violent Storms: At times, the meeting line of a
warm and a cold current may cause a violent
storm. The hurricanes which occur off the coast
of USA follow the line where the Gulf Stream
merges with the Labrador Current.
The mixing of warm and cold currents results in
the deposition of plankton. Therefore, at such
places, fish can be found in abundance.
Currents help the ships to sail if they follow the
directions of the currents.
Many warm currents keep the ports of Europe
ice-free even during the winters. This helps in
trade and commerce.
The ships face danger because of the fogs caused by the
meeting of the warm currents with the cold currents. This has
resulted in the wreckage of many ships in the past as they
were not able to view icebergs because of poor visibility.
