Describe the causes of origin, structure and weather associated with tropical cyclones
Tropical cyclones are some of the
most powerful storms on Earth. They are known by different names in different
regions—hurricanes in the Atlantic Ocean, typhoons in the Pacific
Ocean, and cyclones in the Indian Ocean. Even though the names differ,
they all mean the same type of storm. In this article, we will describe in
simple words the causes of origin, the structure, and the weather
associated with tropical cyclones.
Causes of Origin of Tropical Cyclones
Tropical cyclones do not form
everywhere. They need special conditions to begin and grow. The main causes of
their origin are:
1.Warm
Ocean Water
o
Cyclones form over oceans where the
surface water temperature is at least 26°C (79°F) or more.
o
The warm water provides the heat and
moisture needed for the storm to develop.
2.Moist
and Unstable Air
o
Warm water makes the air above it
hot and full of water vapor.
o
When this moist air rises, it cools
and condenses into clouds, releasing heat. This heat energy feeds the cyclone.
3.Coriolis
Force
o
The rotation of the Earth causes
moving air to turn. This turning effect is called the Coriolis force.
o
Without this force, cyclones cannot
spin. That is why cyclones do not form near the equator (within 5° latitude),
because the Coriolis force there is too weak.
4.Low
Pressure at the Surface
o
Rising warm air creates a low-pressure
area at the ocean surface.
o
Surrounding air rushes in to fill
the gap, but because of the Coriolis force, it starts rotating around the
center.
5.Little
or No Wind Shear
o
Wind shear means a big difference in wind speed or direction at
different heights.
o
If wind shear is too strong, it
breaks the cyclone apart.
o
Tropical cyclones need calm or
uniform wind conditions in the upper atmosphere so they can grow vertically.
6.Disturbance or Trigger
o
Sometimes, a weather disturbance
like a thunderstorm, a wave in the atmosphere, or the meeting of two winds acts
as the “spark” to start a cyclone.
So, in simple words, tropical
cyclones are born when warm ocean water, moist air, Earth’s rotation, low
pressure, and calm winds all work together.
Structure of Tropical Cyclones
Even though cyclones are very large,
their structure is organized and has some common features.
1.Eye
o
At the very center of the cyclone is
the eye.
o
The eye is usually 20–50
kilometers wide.
o
It is the calmest part of the storm,
with light winds and clear skies.
o
Air here sinks, which is why it is
clear and calm.
2.Eye
Wall
o
Around the eye is the eye wall,
which is the most dangerous part of the cyclone.
o
It has very strong winds, heavy
rainfall, and tall clouds.
o
The eye wall contains the maximum
destructive power of the storm.
3.Rain
Bands
o
Spiral bands of clouds and rain
stretch out from the eye wall.
o
These are called rain bands.
o
They bring bursts of heavy rain,
thunderstorms, and strong winds.
o
Between the bands, there may be
short breaks of calm weather.
4.Cloud
System
o
The cyclone has a huge cloud system
that can spread hundreds of kilometers across.
o
These clouds are high and thick,
covering large parts of the ocean and land.
5.Height of the Storm
o
Cyclones are not just wide but also
tall.
o
The clouds can reach up to 12–15
kilometers high in the atmosphere.
In short, the cyclone’s structure is
like a spinning wheel, with a calm center (eye), a violent wall (eye wall),
and spiral rain bands around it.
Weather Associated with Tropical Cyclones
Tropical cyclones affect weather in
many ways. The weather changes before, during, and after the cyclone.
1.Before
the Cyclone Arrives
o
The sky becomes cloudy.
o
Winds start to blow strongly.
o
The air feels hot, humid, and heavy.
o
The sea becomes rough with high
waves.
2.During
the Cyclone
o
Strong
Winds: Winds can reach speeds of over 200
km/h in powerful cyclones. These winds uproot trees, destroy houses, and
bring down power lines.
o
Heavy
Rainfall: Rain pours heavily, causing floods
and waterlogging. Rivers overflow, and low-lying areas are covered with water.
o
Storm
Surge: This is one of the deadliest parts
of a cyclone. Strong winds push ocean water toward the shore, raising the sea
level by several meters. Storm surges flood coastal areas and cause great
destruction.
o
Thunder
and Lightning: Many cyclones are accompanied by
thunderstorms and lightning strikes.
3.Eye
of the Cyclone
o
When the eye passes over a place,
the weather becomes suddenly calm.
o
The sky may even look clear for a
short time.
o
But this calm does not last long,
because the other side of the eye wall arrives soon with violent winds and rain
again.
4.After the Cyclone
o
Rain may continue for some time, but
winds start to weaken.
o
Flooding, broken roads, damaged
houses, and fallen trees remain as the effects.
o
Sometimes, diseases spread due to
dirty and stagnant water.
Tropical cyclones are natural storms
that form over warm oceans when the right conditions come together. Their origin
depends on warm water, moist air, Earth’s rotation, low pressure, and calm
winds. Their structure is special, with a calm eye in the center, a
violent eye wall, and spiral rain bands. The weather they bring includes
strong winds, heavy rain, thunderstorms, and dangerous storm surges.
Even though cyclones cause destruction, understanding them helps us prepare better. Weather forecasts, early warnings, and safe shelters save many lives today. Nature’s power cannot be stopped, but knowledge and preparation can reduce the damage.
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