Global Hazards Flashcards
what is the global circulation system driven by?
- warm air rising causing low pressure
- cool air sinking causing high pressure
list all cells (3)
polar, Hadley and ferrel
what affects temperatures around the world? (6)
- insolation
- albedo effect
- cloud cover
-surface winds & ocean currents - land and sea
-altitude
where is insolation the strongest?
the equator
where is insolation the weakest?
at the poles
what is wind?
the movement of air from an area of high pressure to one of low pressure
why are some areas so windy? (5)
- trade winds
- katabatic winds
- jet streams
- tornadoes
- tropical storms
what is precipitation?
water falling from the atmosphere as rain, sleet, snow or hail
where do tropical storms occur? (and explain)
they form over tropical oceans and move from east to west. they have wind speeds of over 120km/h and can be up to 650km across. they bring heavy rain.
where do droughts occur? (and explain)
periods where there is much less precipitation than usual for the area, leading to water shortages, also is linked to long periods of high pressure.
what causes tropical storms to form?
the ocean being 26.5 degrees + and at least 60m deep.
what do tropical storms bring, and what can they cause?
strong winds, heavy rainfall and coastal flooding, causing flash floods, mudslides and landslides.
explain the El Niño effect
the trade winds that blow from east to west are weaker, the surface temperature will then increase.
explain the La Niña effect
the winds are stronger, the temperature then decreases.
how are El Niño and La Niña linked to drought?
el nino events result in less rainfall on the Australian/asian edge of the Pacific Ocean and more on the north and South American edge. La Niña events reverses this.
what is the earths structure made up of?
crust, mantle, outer and inner core.
what are plate boundaries and what do they cause?
where two plates meet. plate movements cause earthquakes and volcanoes.
what are destructive plate boundaries?
an oceanic plate meeting a continental plate, the denser oceanic plate is forced under the continental plate- it is subducted.
what are collision plate boundaries?
two continental plates move towards each other, they then collide.
what are constructive plate boundaries?
oceanic plates pulling apart.
what are conservative plate boundaries?
tectonic plates moving past each other
at what range (of km) below the surface can deep focus earthquakes start?
70-700km
what plate boundaries do deep focus earthquakes occur at?
destructive plate boundaries
shallow focus earthquakes start within …km of the surface
70km
