global hazards one Flashcards
what is wind
movement of air caused by differences in pressure
where do wind move to
from areas of high pressure to areas of low pressure
what does warm rising air create
low pressure
what does cool falling air create
high pressure
what are the order of the wind cells
polar
Ferrell
Hadley
Hadley
ferrel polar
draw and earth to show the surface winds and cells
…
how does precipitation occur
-when warm wet air rises and cools, causing water vapour to condense
where would you expect precipitation to occur the most
in low pressure belts where air rises
what are tropical storms
intense low pressure weather systems, with heavy rain and strong winds that spiral
how do tropical storms develop
-when the sea temperature is 27 degrees or higher
-condensation when warm air rises and cools releases huge amounts of energy.
-the rising air creates low pressure which increases wind speed
how are extreme winds created in a tropical storm
caused by an area of very low pressure at the centre of the storm compared to its outside
where and when do most tropical storms occur
between 5 degrees and 30 degrees north and south of the equator in late summer and autumn
what are the normal conditions like in the Pacific Ocean
-low pressure over the west and high pressure over east
-west have rain and thunderstorms and east have clear skies and dry weather.
why are the normal conditions over the pacific ocean like this
-trade winds over ocean blow west moving warm surface water to Australia causing air to rise creating low pressure.
-in the east, rising cold water from the ocean and wind high in the atmosphere causes high pressure.
what is La Niña
when the normal conditions over the pacific become more extreme and trade winds blow west more strongly causing more cold water to rise in the east.
