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Flashcards in Clouds Deck (7)
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what is the global atmospheric circulation model

it suggests the presence of three interconnected cells and identifies latitudinal zones of rising and falling air


explain what occurs in the global atmospheric circulation model at the EQUATOR

high temperatures result in high rates of evaporation. the war, moist air rises, cools and condenses to form towering blocks of cloud and heavy rainfall in a low pressure zone called the ITCZ (inter-tropical convergence zone)


explain what occurs in the global atmospheric circulation model at MID LATITUDES

cloud formation is mainly driven by the convergence of warm air from the tropics and cold air from the Arctic.
the boundary of these 2 distinct air masses (the polar front) results in cloud formation.
the jet stream drives these unstable weather conditions across the mid latitiudes


clouds form when the air is too saturated and cannot hold anymore water vapour. this can happen two ways:

the amount of water in the air has increased- eg through evaporation- to the point where the air cannot hold anymore water
the air has cooled to its dew point- the point where condensation occurs so the air is unable to hold anymore water


the warmer the air is...

the more water vapour it can hold


the point at which dew point is reached and clouds formed is called...

the condensation level


as air cools it is able to hold less water vapour so.... (link to temperature)

if it is cooled sufficiently it cannot hold anymore water so becomes saturated (eg dew in the morning)-- this temperature is known as the dew point temperature