Flashcards in 2.2- Weather Hazards and drought case studies Deck (18)
How do tropical cyclones form?
Tropical cyclones form in warm ocean areas (27*)
1)rising warm air causes thunderstorms which group together making a strong flow.
2)An area of very low pressure form at the centre of the storm (the eye- the calmest area)
3)the storms rotate,accelerating in and are forming a tropical cyclone.
When in the year, do tropical cyclones form?
June-November in the northern tropics
November-April in southern tropics
What are the tropical cyclone characteristics?
•very low pressure
•form a cylinder of rising, spiralling air surrounding an eye of descending,high pressure air
•cloud banks called the eye wall surround the eye
•often 400km wide and 10km high.
What are 5 hazards associated with tropical cyclones?
What does Arid mean?
In ARID areas, the Normal climate is dry because they normally have high pressure which leads to low precipitation.
What are some factors of Arid environments?
•permanent low precipitation
•10-250 mm a year (precipitation)
•high pressure conditions
•mostly located in the tropics
What are some drought conditions?
•(in U.K.) drought is 15 days without rain
•located anywhere gloabally
What are the two natural causes of drought?
Meteorological and hydrological
What does meteorological mean?
This is where an area receives less than average precipitation.
What does hydrological mean?
This is where the hydrological cycle receives less rainfall than normal.
What are 2 human causes of drought?
Deforestation- trees reduce evaporation, store water and add to atmospheric moisture.
Damn building- restricts the flow of water, which lowers water levels further down stream.
How does global circulation make some areas more vulnerable to drought?
Where Hadley and Ferrel cells circulate, descending dry air means there's little precipitation. If the rain doesn't come in wet season, the area has drought conditions
What are the main 3 reasons why droughts are hazardous?
•subsidence- (groundwater levels drop causing land to settle at lower level)
Which under-developed country suffered from severe drought in 2015?
What are the 3 main impacts on people from the California drought?
•risk to people's lives and property
•loss of food income
What are the 2 main environmental impacts from the California droughts?
•air pollution destroyed habitats and wildlife
•impact on wildlife (e.g rivers too low for salmon to breed)
What are the 3 main impacts on people from the Ethiopian drought?
•death of livestock causes food crisis
•people eat less and become ill and malnourished
•girls have to walk further to get water so cannot go to school.