Himansu 28102024
Q. What are the differences between a tropical and extra-tropical cyclone? Describe the conditions needed and
process of formation of a tropical cyclone. (GS 1; 15 Marks; 250 Words)
Tropical and extra-tropical cyclones
are two distinct types of storm
systems that differ in their
formation, characteristics, and
associated weather conditions.
Differences Between Tropical and
Extra-Tropical Cyclones:
1. Formation Location:
Tropical: Form over warm ocean
waters, within the tropics
between latitudes 0 and 30
degree.
Extra-Tropical: Form over land or
sea in mid-latitude regions.
2. Temperature Structure:
Tropical: Warm-core systems,
centre of the cyclone is warmer
than the surrounding
environment.
Extra-Tropical: Cold-core systems,
with the centre being cooler than
the surrounding areas.
3. Energy Source:
Tropical: Driven by the heat and
moisture from warm ocean
Ex: Tropical Cyclone Dana,2024, Extratropical
cyclone : Storm Daniel ,2024
waters.Extra-Tropical: Driven by
temperature gradients between
air masses, associated with fronts
and the jet stream.
4. Weather Features:
Tropical: strong winds, heavy rain,
and a well-defined eye.
Extra-Tropical: thunderstorms,
tornadoes in the warm sector and
winter storms in colder months.
5.Lifecycle:
Tropical: can last for weeks and
weakens quickly when moving
over land or colder waters.
Extra-Tropical: Can persist for
longer periods and can change
and evolve more significantly over
time.
Conditions for Tropical Cyclone
Formation:
1. Warm Ocean Waters: at least
26-27°C.
2. Atmospheric Instability: Warm,
moist air rises, creating a low-
pressure area at the surface.
3. Low Wind Shear: change in wind
speed
and direction with height must be
low for storm development.
4. Pre-existing Weather
Disturbance: Existing
thunderstorms or tropical waves.
5.Coriolis Effect: The rotation of the
Earth causes the rising air to
spin.
Process of Formation of a Tropical
Cyclone:
1. Development of a Low-Pressure
Area: Warm, moist air rises and
cools, leading to condensation
and cloud formation. This releases
latent heat, further warming the
air and causing it to rise.
2. Formation of a Cyclonic
Circulation: The Coriolis effect
causes the rising air to rotate,
forming a cyclonic circulation.
3. Intensification: As the system
organizes, it can form a tropical
depression, then a tropical storm,
and finally a hurricane.
4. Mature Stage: The cyclone
reaches its mature stage with a
well-defined eye, eyewall, and
spiral rainbands. The strongest
winds and heaviest rains occur in
the eyewall.
5.Dissipation: The cyclone weakens
when it moves over cooler waters
or land, losing its heat source, or
encounters high wind shear.
Understanding these differences
and processes is essential for
predicting the behaviour and
potential impacts of these storm
systems.
