Ocean Circulation Waves Tides & Current Video Lecture | Geography for Class 7

ocean movements surface currents in this
module you will learn about surface
ocean currents its types and its
circulation in ocean water just as air
has a circulation pattern so do oceans
circulation pattern of oceans depends on
ocean currents which in turn depend on
differences in temperature density
pressure forces of wind and gravity a
current is the regular and generally
horizontal flow of ocean water in a
definite direction ocean currents are
the most powerful movements as they
drive water for thousands of kilometres
they help steer ships and animals in
water there are two types of portion
currents surface and deep
the surface ocean currents circulate in
the upper layers of the ocean
whereas deep ocean currents circulate in
the deep ocean in this module you will
focus on the surface currents and their
circulation across the globe surface
currents are mainly powered by winds
when winds blow over the ocean it
creates friction between the air and the
water this friction helps the wind to
drag along the upper thin layer of the
ocean this top layer of the ocean pulls
along the next layer the impact of the
frictional force exerted by the air
lessens as the depth of the ocean
increases thus the wind dies out a few
hundred metres below the ocean's surface
in this way the wind causes surface
currents would circulate on the surface
of the ocean observe the map showing the
circulation of surface currents you
might notice that the currents mainly
have circular patterns called gyres but
why do these gyres move in a circular
pattern
the circular patterns of surface
currents are mainly caused by the
Earth's rotation
and bordering land masses in the
northern hemisphere the Earth's rotation
causes the winds which drive surface
currents to deflect to earth the right
and in the southern hemisphere
the winds help the surface currents to
deflect towards the left this is called
the Coriolis effect also bordering land
masses modify the path of these currents
to rotate clockwise in the northern
hemisphere and anti clockwise in the
southern hemisphere if you sum in the
map you will observe five major gyres -
in the Pacific Ocean to win the Atlantic
Ocean one in the Indian Ocean in
addition to these there is one major
surface current circulating around
Antarctica the surface ocean currents
can broadly be classified into two types
warm currents and cold currents these
currents help in the exchange of heat
between low and high latitudes
one currents originated near the equator
where the temperatures are high from
here these currents flow towards the
poles where the temperatures are low
these currents carry warm water with the
equatorial region to temperate and polar
regions and raise the temperatures on
land the Gulf Stream is an example of a
warm current that originates at the tip
of Florida and flows along the eastern
coast of North America and reaches the
western coast of Europe since it
originates from a warm region it's warm
water keeps Europe warmer than the other
areas at similar latitudes cold currents
originate near the poles where the
temperatures are low from here these
currents flow towards the temperate and
equatorial regions these cold currents
carry cold water and lower the
temperatures on land the laboratory is
an example of a cold current which
originates in the Arctic Ocean it flows
between Labrador and Greenland to the
coast of Newfoundland Nova Scotia and
New England in this module you have
learned an ocean current is the regular
and horizontal flow of ocean water in a
definite direction and help the transfer
of heat from low to high latitudes and
vice-versa there are two types of ocean
guns surface and deep the surface
currents circulate in the upper layers
of the ocean whereas the deep ocean
currents circulate in the depths of the
ocean floor surface currents are powered
by winds and move in circular patterns
called gyres
the surface currents are of two types
warm currents and cold currents warm
currents flow from the equatorial region
towards the poles example the Gulf
Stream cold currents flow from the poles
to earth the equator example the
Labrador Current
you