Tropical Cyclones Flashcards
What temp do tropical cyclones form and where
They form at sea temp of aprox 26.5°C or higher and when there is a change in wind shear is low. At the source of most of the cyclones at 5° to 30° at the tropic of cancer and capricorn
What times are cyclones usually forming
NH it is june - november
SH is november - april
How do cyclones begin to form
warm moist air rises and condenses releasing huge amount of energy. The risng air create low pressure which increases the surface winds. As air rises it creates a drought, new air rushes to replace it creating a cycle
How does earth’s rotation effect cyclones
Earth’s rotation deflects the paths the winds, causing the cyclone to spin.
What direction do cyclones go
CYCLONES move west from the eastery winds but as they move a way from the equator their path starts to curve east as they get to mid-lattitude westerlies.
Why do cyclones get stronger
They intensify due to them gaining more energy from the warm water
Why do cyclones lose strength
They dissipate when they move on ground or cooler water as the energy supply is cut off. (Also change of windspeed).
list Structural features of cyclone
- Usually last 7-14 days
- Hudrends of km wide
- Centre eye can be up to 50 km across with lowpressure and clear sky (high temp)
- Spiralling rising air eyewall with very strong winds (160kmph) with storms (low temp)
- spin anticlockwise in NH and opposite SH
- towards the edges the wind speed falls with smaller clouds
- cumulonimbus clouds
- top is dense cirrus canopy
How are cyclone eyes formed
By decending air and the earth’s roatation making it spin (coriolos force)
What are the physical hazards of cyclones
High windspeeds (250km/h) Intense rainfall Storm surges Landslides Coastal erosion
Social imapcts not as obvious from cyclones
Electrical supply cut off Contaminated water from sewage floods Shortage of food from loss of crops and livestock Unemployment Damaged roading
Imapct of fresh water from cyclone
Freshwater polluted from saltwater
Physicsl vulnerabilities from cyclones
Low-lying coastlines
Areas in pathway
Inlands
Steep hillsides
Socail vulnerabilities from cyclones
Poorer countries cant afford good quality materials
Healthcares may not be good
Little money for flood defenses or training emergency teams
Poor infrastructure so harder to rescue people
economic vulnerabilities from cyclones
Many people depened on agriculture
No insurance to conver repairments
(However, economic impact could be greater in richer countires as damage is woth lots more)
