Atmospheric circulation Flashcards
What are winds?
Winds are large scale air movements
What causes winds?
Differences in air pressure
How does air pressure cause winds?
Wind moves from areas of high pressure to areas of low pressure
What are Westerlies?
Westerlies are surface winds that blow in the direction of the poles. In the Northern Hemisphere, the blow from the south-west
What are trade winds?
Trade winds are surface winds that blow in the direction of the equator. In the Northern Hemisphere, they blow from the North-East
Where do surface winds blow from and to?
Winds blow from high pressure areas to low pressure areas
What is global atmospheric circulation?
The circular movements of the Earth’s atmosphere. The circular movements of air are known as cells, which all join together to form the circulation of the Earth’s atmosphere
What are the 3 main cells in the global atmospheric circulation model? (Pole to Equator)
Polar Cell, Ferrell Cell, Hadley Cell
What is high pressure and where on the global atmospheric circulation model would you wind high pressure?
When air sinks towards the ground, high pressure is formed.
It happens at 30°N and 30°S of the equator, 90°N (North Pole) and 90°S (South Pole)
What is low pressure and where on the global atmospheric circulation model would you find it?
When air is rising from the surface of the ground, low pressure is formed
It happens at 0° (the equator), 60°N and 60°S of the equator
Describe what happens in the Hadley Cell
Warm air rises at the equator, travels North and South and sinks around 30°N and S. It then travels back to the equator
Describe what happens in the Ferrell Cell
Warm air rises at 60°N and S, back towards the equator. Cool air sinks at 30°N and S of the equator
Describe what happens in the Polar Cell?
Cool air descends at 90°N and S (the poles) then the air moves back towards the poles
What are deep ocean currents caused by?
Differences in water density
What are surface currents caused by?
Global wind patterns, the rotation of the Earth, and the shape of the ocean basins.