1. Air Movement
Chapter 4 – Section 3
Pages

2. Wind
The movement of air from an area of high pressure (more dense) to an area of low pressure (less dense)

3. Warm air rises and cold air sinks.
Global Winds
Wind current on a global scale.
Warm air rises and cold air sinks.
Temperature Differences
Rising and sinking air makes pressure differences
Pressure Difference

4. Global Temperature Patterns
The sun’s rays are weaker near the poles causing less warming. The air here is cool.
Cool air sinks.
The sun’s rays are stronger near the equator causing more warming. The air here is warm.
Warm air rises

5. Air moves between the equator and the poles.
Global Winds
Hadley Cells.
Air moves between the equator and the poles.
Global Winds

6. The Coriolis Effect Mr. Fetch’s Earth Science Classroom
The Earth’s rotation causes air to turn to the right in the Northern Hemisphere and to the left in the Southern Hemisphere
Mr. Fetch’s Earth Science Classroom

7. Global Winds Remember, winds are named from where they come. 60°N 30°N
Polar Easterlies - From 90°N to 60°N - Deflected to right
60°N
Prevailing Westerlies - From 30°N to 60°N - Deflected to right
30°N
Easterly Trade Winds - From 30°N to O° - Deflected to right
Doldrums 0°
Easterly Trade Winds - From 30°S to 0° - Deflected to left
30°S
Prevailing Westerlies - From 30°S to 60°S - Deflected to left
60°S
Polar Easterlies - From 90°S to 60°S - Deflected to left

8. Doldrums Low Pressure Zone (warm, less dense air) along the equator
Heated air expands creating a zone of low pressure
Very little wind
Rains nearly every afternoon

9. Polar Easterlies 90˚ - 60˚ latitude Winds move east to west
Winds rise at 60˚ latitude and sink
at the poles
Bring us the cold polar air

10. Prevailing Westerlies
60˚ - 30˚ latitude
Winds move west to east
Winds rise at 60˚ and sink at 30˚
Move weather systems across the
United States

11. Easterly Trade Winds 0˚ - 30˚ latitude Winds move east to west
Winds rise at the equator and sink at 30˚
Early sailors used winds to navigate
trade routes

12. Jetstreams
Narrow belts of strong winds near the top of the troposphere
Winds move west to east - faster in winter
Form between cold dry air and warm moist air
Produce large weather systems
Jets fly faster when flying with Jet Stream

13. Jet Stream

14. Sea Breeze
Convection current of air created during the day from the sea to land
Land warms faster than the sea. Warm, less dense air over land rises; cooler, more dense air over sea sinks, creating a cool breeze to blow in from the sea

15. Sea Breeze

16. Land Breeze
Convection current of air created at night from the land to sea
Land cools faster than the sea. Cooler, more dense air over sinks and moves towards the sea; warmer air over the sea rises, creating a breeze from land to sea

17. Land Breeze