Causes of Tropical Cyclones
The development of cycle of tropical cyclones may be divided
into three stages
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Formation and initial development |
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Full maturity and |
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Modification or decay |
Formation and initial development stage
Four atmospheric and oceanic conditions are necessary for development
of a cyclonic storm: -
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A
warm sea temperature in excess of 26 degrees
centigrade to a depth 60 m. which provides abundant water
vapors in the air by evaporation. |
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High relative
humidity of the atmosphere to a height of above 7000 m facilitates
condensation of water vapors into water droplets and clouds;
releases heat energy thereby inducing a drop in pressure.
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Atmospheric instability encourages formation of massive vertical cumulus cloud
convection with condensation of rising air
over ocean.
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A location of
at least 4-5 latitude degrees from the equator allows the influence
of the forces due to the earth's rotation to take effect
in reducing cyclonic wind circulation around low-pressure
centers.
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Modification or Decay
A tropical cyclone begins to weaken in terms of its central low
pressure, internal warm core and extremely high winds as soon
as its source of warm most air begins to ebb or is abruptly cut
off. The weakening of a cyclone does not mean the danger to life
and property is over. When the cyclone hits land, especially
over mountainous or hilly terrain, revering and flash flooding
may last for weeks.
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