Page 119 - SST Class 06

degrees, minutes and seconds. Geocentric latitude warm. It has a wet and dry season, but does
is the arc subtended by an angle at the earth’s not experience the four seasons familiar to
centre and measured in a north-south plane residents of the temperate zones further
poleward from the Equator. Thus, a point at from the equator. The warmth of the torrid
30°15'20'' N subtends an angle of 30°15'20'' at zone influences its weather, ecosystems and
the centre of the globe; similarly, the arc between geographic features. Most of the southern
the Equator and either geographic pole is 90° half on India, which lies below the Tropic of
(one-fourth the circumference of the earth, or Cancer, lies in this zone.
(1/4 × 360°), and thus the greatest possible 2. Temperate Zones : The temperate zone is
latitudes are 90° N and 90° S. As aids to indicate the part of the earth between the Tropic of
different latitudinal positions on maps or globes, Cancer and the Arctic Circle in the Northern
equidistant circles are plotted and drawn parallel Hemisphere or between the Tropic of
to the Equator and each other; they are known Capricorn and the Antarctic Circle in the
as parallels, or parallels of latitude. Southern Hemisphere, having a climate that

Important Parallels of Latitudes is warm in the summer, cold in the winter
Between 0° and 90° latitudes in either hemi- and moderate in the spring and fall. It is
sphere of the earth, there are two important considered to be the most varied climate
parallels of latitude in each hemisphere which system in the world and is divided into two
correspond with dividing lines of heat zones of main types: the maritime and the continen-
the earth. Since the earth rotates on its axis and tal.
follows a regular path around the sun, certain 3. Frigid Zones : Frigid zone is the area
parts of the earth receive more solar energy than between the Arctic Circle and the North
various other phenomena happen as a matter of Pole or between the Antarctic Circle and the
routine. The important parallels are the follow- South Pole.
ing: This climate is characterised by a long season of
Tropic of Cancer : It lies at the angular dis- severe winter and even the summer season is
tance of 23½° N. cold. The precipitation is very low, generally
Tropic of Capricorn : It lies at the angular below 30 cm. and due to low temperatures the
distance of 23½° S. vegetation is practically missing. Only during the
Arctic Circle : 66½° N of the equator.
Frigid Zone
Antarctic Circle : 66½° S of the equator.
Heat Zones of the Earth North
Temperate Zone
The above parallels of latitudes mark the limits of
those portions of the earth where maximum or
Equator
minimum solar energy is received. Based on this, Torrid Zone
there are three major heat zones of the earth as
shown in the figure.
South
1. Torrid Zone : The torrid zone refers to the Temperate Zone
area of the earth near the equator. As its Frigid Zone
name suggests, the torrid zone is generally
Heat Zones

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