8. TROPICAL CYCLONE STRUCTURE
A tropical cyclone, on the average, has a
total diameter of 550 km but can have a
diameter more than 2000 km wide. Its basic
structure is composed of an eye, an eye wall,
and surrounding rain bands.
9. EYE
It is the lowest atmospheric pressure in the
structure of a tropical cyclone.
In the eye, with diameter which may span 20-65
km wide, winds are weak, the temperature is
warm, and the sky is clear- everything is calm and
it is as if no weather disturbance is going on in a
region over which the eye passes.
10. EYE WALL
The region immediately surrounding the
tropical cyclone’s center and which can reach
as high as 15km above mean sea level, brings
the strongest winds, heavy rains, and
turbulence shortly after the passage of the
eye.
13. WHY DO TROPICAL CYCLONES FORM?
Tropical cyclones form as a result of the
atmosphere’s natural tendency to maintain
equilibrium by redistributing heat through
wind from the equatorical regions to the polar
regions. This mechanism prevents the tropical
areas from getting excessively hot and the
polar regions from becoming extremely cold.
14. IMPORTANCE OF TROPICAL CYCLONE
If not for tropical cyclones, there would be severe
environmental imbalances.
Rainfall brought by tropical cyclones replenishes ground
water and surficial water.
Flora and fauna in the Philippines are heavily reliant on
tropical cyclones for source of water.
50% of average annual rainfall in the country is derived
from typhoon-related rainfall.
15. HOW DO TROPICAL CYCLONES FORM?
Tropical cyclones form both in northern and southern hemisphere at
latitudes 5 to 30 degrees away from the equator(trade wind belt) in parts of
the open ocean where water temperatures reach at least 26 degrees
Celsius to depth more than 60 meters.
Air masses increasingly heats up and rise.
Mainly due to Coriolis effect.
Drier air from higher altitudes is sucked into the center of tropical cyclone
preventing the formation of clouds and, therefore rainfall. This explains
why the “eye” of the tropical cyclone is calm.
16. EFFECTS OF TROPICAL CYCLONE
STRONG WINDS- which cover a much larger area during tropical
cyclones, cause the most obvious damage.
STORM SURGE- localized unusual increase of sea water level
way above the predicted asrtronomical tide level, happens
primarily due to intense winds and lowered atmospheric
pressure that accompany intense tropical cyclones passing from
the sea to land.
HEAVY RAINS- unlike strong winds and storm surges, actually
occur in tropical cyclones of lower intensity. Flooding due to
heavy rains is usually worse during tropical depressions and
tropical storms.