weather hazards section A(p1) Flashcards
what is global atmospheric circulation?
the transfer of heat from the equator to the poles by movement of air.
name the three atmospheric cells
Hadley cell
Ferrel cell
Polar cell
how does the air move through the cells? (4 MARKER)
1)the sun heats the earth at the equator (low pressure)
2) as the air rises it cools and moves away from the equator
3) 30 degrees north and south, cool air sinks (high pressure)
4) at the ground the cool air either moves to the equator as trade winds or the poles as westerlies.
5) 60 degrees north and south the warm surface winds meet cold polar winds resulting in warm air rising(low pressure)
6) some air moves back towards the equator and the rest moves to the poles
7) at the poles cool air sinks resulting in high pressure which is drawn back to the equator.
what is the Coriolis effect?
the winds in the earths atmosphere curve due to the earths rotation.
e.g. trade winds and westerlies.
how does the air move through the cells? (2 MARKER)
as hot air rises pressure is low
as cool air sinks pressure is high
name the three tropical storms and how they are distributed
Hurricanes - USA, Atlantic
Typhoons - Japan, western pacific
Cyclones - India , eastern Africa, Indian ocean
DON’T STATE TORNADOS - they only happen on land
where are tropical storms distributed
water based as oceans are there energy source
hard to predict as they are highly erratic
cannot form on the equator due to low pressure and Coriolis effect
found between 5-30 degrees north and south of the equator.
how do tropical storms form?
found between 5-30 degrees north and south of the equator
sea temp is 27 degrees or higher
low wind speeds (keeps the storm intact )
the evaporation and condensation of warm surface waters releases huge amounts of energy producing powerful storms
they spin due to the Coriolis effect
How are tropical storms measured?
On the Saffir-Simpson scale of wind speeds.
Category 1: 74-95mph
Category 2: 96-110mph
Category 3: 111-129mph
Category 4: 130-156mph
Category 5: 157mph+
Where do surface winds blow from and to?
Winds blow from high pressure areas to low pressure areas
Describe what happens in the Hadley Cell?
Warm air rises at the equator, travels North and South and sinks around 30°N and 30°S. It then travels back to the equator (low pressure)
Describe what happens in the Ferrel Cell?
Warm air rises at 60°N and 60°S equator, back towards the equator. Cool air sinks at 30°N and 30°S of the equator. (high pressure)
Describe what happens in the polar Cell?
Cool air descends at 90°N (north pole) and 90°S (south pole) then the air moves back towards the equator.(low pressure)
Describe the formation of a tropical storm?
Warm wet air from the warm ocean rises. As it cools and condenses it creates huge cumulonibus clouds.
As the warm, wet air is rising, it creates an area of low pressure near the ocean surface. Warm air from outside the storm is sucked in to fill this ‘space’ creating a constant upwelling of warm, moist air to power the storm.
Air leaves the spiralling column in the centre of the storm out of the top and flows downwards to the side of the storm.
Describe the features of a tropical storm?
Up to 300 miles wide
Wind speeds up to 252km/h and above
Thunder and lightning, strong winds at the eye wall
eye of the storm is very calm with no rain, no winds, low pressure and high temperatures
Describe the primary effects of Typhoon Haiyan?
6,300 deaths
600,000 people forced to leave their homes
30,000 fishing boats destroyed
90% of city of Tacloban destroyed
Tacloban airport severely damaged
Infrastructure destroyed by winds
Flooding
Describe the secondary effects of Typhoon Haiyan?
6 million lost jobs
Flooding caused landslides, blocking roads meaning aid was hindered
Power cut off
Difficulty receiving aid as a result of damaged infrastructure
Outbreaks of disease due to poor sanitation and shortages of shelter and water.
Looting and violence broke out
Describe the immediate responses to Typhoon Haiyan?
Aid agencies donated food, water and shelter quickly
US aircrafts helped with search and rescue
1,200 evacuation centres were set up
The UK provided Shelter Boxes which provided equipment to set up make-shift homes
The Philippines Red Cross delivered basic food packages
Describe the long term responses to Typhoon Haiyan?
Infrastructure was rebuilt e.g. bridges and airport
Charities helped to replace fishing boats which is a crucial source of income for many citizens
‘Cash for Work’ programmes paid people to clean up debris
Homes rebuilt away from flood prone areas
Rice farming was quickly restored to ensure food production and a source of income
How are tropical storms monitored and predicted?
Predicting the track of a tropical storm is very difficult.
Satellite images are used to identify the distinct pattern of clouds associated with tropical storms forming over the ocean.
Aircrafts can be used to monitor conditions within tropical storms.
In the USA, ‘Hurricane Watch’ advises that hurricane conditions are likely. ‘Hurricane Warning’ is issued when people should take action e.g. evacuate.
How do people protect themselves from tropical storms?
Secure outdoor furniture to the ground
Cut own tree branches to avoid property damage
Window shutters
Buildings built on stilts to prevent storm surge damage
Storm drains in urban areas removed large amounts of water from storm surges
Sea walls built to hold back some water from storm surges
How do people plan for tropical storms?
Increasing citizens awareness and knowledge of what to do in the event of a tropical storm
e.g. family evacuation plans / emergency kits
Educating people on the dangers of tropical storms and how best to prepare
How might climate change affect tropical storm distributon, frequency and intensity?
Distribution: More tropical storms may happen outside of the current areas as sea temperatures increase.
less frequent, greater magnitude
