Global atmospheric circulation Flashcards
Air always moves from
high to low pressure, this generates wind
Why is there a pressure difference
sun heats the earth surface unevenly
What happens in the cells of the global atmospheric circulation
warm air rises causing low pressure belts, cool air falls causing high pressure belts
What happens at the equator (global atmospheric circulation)
the sun warms the earth which transfers the heat to the air above causing it to rise, which creates a low pressure belt with rising air, clouds and rain, as the air rises it cools and moves out to 30° north and south
What happens 30° north and south of the equator (global atmospheric circulation)
cool air sinks creating a high pressure belt with cloudless skies and very low rainfall
What are the surface winds blowing towards the equator
trade winds
As the cool air reaches the ground surface what happens
it moves as surface winds either towards the equator or towards the poles
Which direction to trade winds blow in the southern hemisphere
south east
Which direction to trade wind blow in the northern hemisphere
north east
When trade winds meet at the equator what happens
they are heated by the sun which causes them to rise and form clouds
What are the surface winds blowing towards the poles
westerlies
Which direction to westerlies wind blow in the southern hemisphere
north west
Which direction to westerlies wind blow in the northern hemisphere
south west
What happens 60° north and south of the equator (global atmospheric circulation)
warmer surface winds meet colder air from the poles, warmer air is less dense than cold air so it rises creating low pressure, some of the air moves back towards the equator and the rest moves towards the poles
What happens at the poles (global atmospheric circulation)
cool air sinks creating high pressure, high pressure air is drawn back towards the equator creating surface winds
