Global Atmospheric Circulation Flashcards
What is global atmospheric circulation?
Global atmospheric circulation is the transfer of heat from the equator to the poles by the movement of air.
(how air moves heat around the world)
Why does air move?
Air moves due to the difference in air pressure.
What is high air pressure?
High air pressure is when cool air descends.
What is low air pressure?
Low air pressure is when warm air ascends.
Describe the process of global atmospheric circulation:
The whole system is driven by the equator, which is the hottest part of the Earth.
Air rises at the equator, leading to low pressure and rainfall.
When the air reaches the edge of the atmosphere, it cannot go any further and so it travels to the north and south.
The air becomes colder and denser, and falls, creating high pressure and dry conditions at around 30° north and south of the equator.
Large cells of air are created in this way.
Air rises again at around 60° north and south and descends again around 90° north and south.
Global atmospheric circulation creates winds across the planet and leads to areas of high rainfall, like the tropical rainforests, and areas of dry air, like deserts.
