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AREAS
OF MODERATE RAINFALL
ü A rainfall is considered to be moderate if it is
between 100 cm and 200 cm.
ü The
states like Madhya Pradesh, Orissa, Bihar, eastern Uttar Pradesh, and eastern
parts of Tamil Nadu experience a moderate rainfall.
AREAS
OF LOW RAINFALL
ü A rainfall is considered to be low if it is between
50 cm and 100 cm.
ü
Some areas like Deccan Plateau,
Western Uttar Pradesh, Punjab, Haryana, eastern Rajasthan, and parts of Kashmir
receive low rainfall.
AREAS OF SCANTY RAINFALL:
These are the areas with a record of less than 50 cm.
Some areas like Western
Rajasthan, Kutch and Saurashtra coast, and north - east Kashmir receive a very
scanty rainfall.
CYCLONE:
ü A
cyclone is an area of low atmospheric pressure.
ü It
is a storm system of great intensity in which winds spiral inwards at great
speeds towards the centre of the system.
ü The
pressure is lowest at the centre.
ü This
closed air circulation is caused by atmospheric disturbances over and above the
earth’s surface, coupled with the earth’s rotation which imparts a whirling
motion to these disturbances.
ü The
Cyclones are associated with destructive and violent disturbances, such as
heavy squalls and torrential rainfall.
ü Winds
in a cyclone in the northern hemisphere spiral inwards in an anti - clockwise
direction.
ü The
Winds in a cyclone in the southern hemisphere move in a clockwise direction.
ü Temperate
Cyclones are also known as extra - tropical or wave cyclones.
ü Temperate
cyclones are active over mid - latitudinal region between 350 and 650 latitude in both hemispheres.
THE MAJOR
AREAS THAT ARE AFFECTED BY CYCLONES ARE:
· The
South - East Carribean region. Here the cyclones are called hurricanes.
· Philippines
islands, eastern China and Japan. Here the cyclones are called typhoons.
· Bay
of Bengal and Arabian Sea. Here they are called cyclones.
· Around
South - East African coast, Madagascar and Mauritius island.
·
North - West
Australia
|
ü The
frequency, intensity and coastal impact of cyclones vary from region to region.
ü Cyclones
are deadliest when they cross the coast bordering North Bay of Bengal (coastal
areas of Orissa, West Bengal and Bangladesh).
ü This
is mainly due to storm surges (tidal waves) that occur in this region
inundating the coastal areas.
ü Tropical
cyclones in the Bay of Bengal are more frequent than in the Arabian Sea.
ü There
could be three reasons for this:
ü Waters
in the Bay of Bengal are comparatively shallow.
ü The
coastline along the Bay of Bengal is more complicated.
ü More
number of rivers drains into the Bay of Bengal than into the Arabian Sea.
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