TROPICAL
CYCLONES
MATRIC IEB
GEOGRAPHY
, Tropical cyclones
factors relating to tropical cyclones
location
tropical oceans- 5-30*C N/S of the equator
occurrence
westwards
affect east coast
dont travel straight as they are deflected due
to coriolos efect to cooler latitudes
Names
Atlantic- hurricanes
North Pacific - typhoons
Indian - tropical cyclones
season
late summer, early autum , so ocean is warm enough due
to prolonged heating
movement of the entire system
east to west -> carried from tropical easterlies
curve eastward (coriolis)
circulation of air within the cyclone
fierce fast winds around a central LP
in southern hemisphere air rises clockwise
energy source
latent heat of condensation - energy given off
when water vapour changes into water
requirements for the formation of TC
atmospheric wide area of
are of warm winds must be undisturbed
instability low pressure
developement extensive light and period of
must exist with closed
between 5*-30* ocean of 27*C variable several days
(rising air) isobars
heat needed for strong winds
corollas needed to convection (rising disrupt air required for rising for cloud
deflects winds in LP hot air) circulation air so there is formation and allows air to
centre and 5*-30* has high humidity = wind shear condensation and formation of circulate
warm oceans increased latent prevents formation latent heat vortex
heat of vortex
, stages of development of a tropical cyclone
stage characteristic diagram
There is convergence of air towards a low
initial pressure centre to create a vortex.
stage/tropical Air pressure is about 1002 hPa and winds
low reach speeds of up to 60 km/h
The intensity of the storm increases as air
continues to converge and rise at the low
pressure centre.
• In the upper atmosphere divergence takes
developing place.
• Pressure continues to drop to about 990
stage/tropical hPa and wind speed increases to about 120
storms km/h.
• The low pressure centre forms an eye and
huge cumulonimbus clouds swirl around the
eye creating a vortex.
• The storm has reached its maximum
intensity.
• Pressure drops to a low of about 950 hPa
and wind speeds exceed 180 km/h.
• The eye is fully developed and is a clear,
mature cloudless centre of the cyclone due to
stage/tropical cooler, subsiding air.
cyclone • The vortex is well developed and the
cyclone may reach up to 600 km in
diameter.
• There is torrential rain, thunder and
lightning associated with a tropical cyclone.
Dissipation occurs when:
•The tropical cyclone cools down when
entering the temperate latitudes.
• When it moves to higher latitudes 30°N
dissipating/dec or S and the sub-tropical HP belt prevents
aying stage uplift.
•When it moves inland because there is no
longer a supply of moisture and surface
friction slows it down.
CYCLONES
MATRIC IEB
GEOGRAPHY
, Tropical cyclones
factors relating to tropical cyclones
location
tropical oceans- 5-30*C N/S of the equator
occurrence
westwards
affect east coast
dont travel straight as they are deflected due
to coriolos efect to cooler latitudes
Names
Atlantic- hurricanes
North Pacific - typhoons
Indian - tropical cyclones
season
late summer, early autum , so ocean is warm enough due
to prolonged heating
movement of the entire system
east to west -> carried from tropical easterlies
curve eastward (coriolis)
circulation of air within the cyclone
fierce fast winds around a central LP
in southern hemisphere air rises clockwise
energy source
latent heat of condensation - energy given off
when water vapour changes into water
requirements for the formation of TC
atmospheric wide area of
are of warm winds must be undisturbed
instability low pressure
developement extensive light and period of
must exist with closed
between 5*-30* ocean of 27*C variable several days
(rising air) isobars
heat needed for strong winds
corollas needed to convection (rising disrupt air required for rising for cloud
deflects winds in LP hot air) circulation air so there is formation and allows air to
centre and 5*-30* has high humidity = wind shear condensation and formation of circulate
warm oceans increased latent prevents formation latent heat vortex
heat of vortex
, stages of development of a tropical cyclone
stage characteristic diagram
There is convergence of air towards a low
initial pressure centre to create a vortex.
stage/tropical Air pressure is about 1002 hPa and winds
low reach speeds of up to 60 km/h
The intensity of the storm increases as air
continues to converge and rise at the low
pressure centre.
• In the upper atmosphere divergence takes
developing place.
• Pressure continues to drop to about 990
stage/tropical hPa and wind speed increases to about 120
storms km/h.
• The low pressure centre forms an eye and
huge cumulonimbus clouds swirl around the
eye creating a vortex.
• The storm has reached its maximum
intensity.
• Pressure drops to a low of about 950 hPa
and wind speeds exceed 180 km/h.
• The eye is fully developed and is a clear,
mature cloudless centre of the cyclone due to
stage/tropical cooler, subsiding air.
cyclone • The vortex is well developed and the
cyclone may reach up to 600 km in
diameter.
• There is torrential rain, thunder and
lightning associated with a tropical cyclone.
Dissipation occurs when:
•The tropical cyclone cools down when
entering the temperate latitudes.
• When it moves to higher latitudes 30°N
dissipating/dec or S and the sub-tropical HP belt prevents
aying stage uplift.
•When it moves inland because there is no
longer a supply of moisture and surface
friction slows it down.
