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Atmospheric Temperature places away from the Equator are colder. This is the
reason that Somalia is very hot while Greenland is
The atmospheric temperature refers to the degree very cold.
of hotness or coldness of the air. Temperature we
feel daily is actually the temperature of the Aristotle , the ancient Greek philosopher classified
atmosphere. It is influenced by these factors : world’s climate into three major zones based on
the main latitudes or the distance of a zone from
Insolation
the Equator or the amount of heat received by the
The incoming solar energy received by the earth is each zone.
called insolation . Amount of insolation decreases Torrid Zone : The torrid zone receives direct
from the Equator to the poles. Therefore, places sunrays, so it is the hottest zone. The zone lies on
situated close to Equator are hotter than places
either side of the Equator upto the Tropic of
situated close to poles. The insolation is greatest Cancer in the north and the Tropic of Capricorn in
when the sun is directly overhead that is around the south. So, the belt is bounded by the 23½°N
noon. When the sun is lower in the sky, the same
and 23½°S latitudes. The sunrays are almost
amount of solar energy is spread over a greater vertical around the year and the region receives
area of ground surface, so insolation is lower. maximum insolation. Days and nights are roughly
Thus, the amount of insolation varies from place
of equal length throughout the year.
to place and from time to time. It also depends on
the angle of the sunrays. Temperate Zone : The temperate zone lies
between the Tropic of Cancer and Arctic Circle in
Insolation
the north and between the Tropic of Capricorn
and the Antarctic Circle in the south. The
temperate zones are neither too hot nor too cold.
Reflected by
atmosphere The sun’s height varies in this zone, so there is a
great difference in the length of a day in summer
Reflected by
clouds and winter. The region receives moderate
insolation so the temperature also vary in summer
Absorbed by and winter.
the atmosphere
and clouds Frigid Zone : The regions between the Arctic
Circle and the North Pole in the Northern
Reflected by Absorbed by Hemisphere and between the Antarctic Circle and
Surface Surface the South Pole in Southern Hemisphere are called
Mean annual global insolation the frigid zone. So we have a north frigid zone
Latitude and a south frigid zone. These zones are the
coldest as they receive extremely slanting sunrays.
The amount of insolation also varies with latitude. These zones receive the least insolation and
As we move away from the Equator towards the experience six months of daylight and six months
poles, the temperature decreases because of the
of darkness.
variation in the angle of the sunrays. It is believed
that the poles received about 40% of the total Just Think!
insolation received at the Equator. So there is less
heat energy available here, with the result that
these areas are very cold. How would you calculate the mean temperature of
a place on a certain day?
Info Bits
Info Bits Distance from the Sea
The water heats up and cools down slower than
As the places near the Equator are hotter and the the land. During daytime, land gets heated very
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