1. Air Movement on Earth

2. Outline What is wind? What causes it?
What are some common wind patterns?
Surface winds
Jet stream
Sea and land breezes

3. Earth is a rocky, inner planet with liquid water on over 70% of its surface.

4. Having two different types of surface (land and water) strongly affects the wind produced on Earth.
Which surface heats up more quickly?
Sand
Which surface cools off more quickly?

5. Which areas of the Earth receive more direct sunlight and therefore are hotter?
Equator gets more direct light and is therefore hotter

6. Do all areas of Earth have the same amount of sunlight all year long?
No! More sunlight hours in summer, therefore it’s hotter.

7. Surface type (land or water) and temperature (affected by direct/indirect light and hours of sunlight) can cause an uneven heating of Earth’s surface.

8. As air molecules heat up, they move apart and become less dense
This is called low air pressure

9. Can you answer this? Warm air rises because it is less dense
Cold air sinks because it is more dense

10. What is Wind?
Wind is the movement of air from an area of high pressure (cold) to an area of low pressure (warm)

11. What areas of Earth will have colder (higher pressure) air?
Air near the poles will be colder and higher pressure.

12. The high pressure air from the poles will flow towards the low pressure areas by the equator
This causes wind
But it doesn’t flow in a straight line as seen in this picture
Why?

13. Wind doesn’t travel in a straight line due to Earth’s rotation on its axis

14. Wind (and water) in the Northern Hemisphere will turn to the right
Wind (and water) in the Southern Hemisphere will turn to the left.

15. We see this spin in hurricanes
N. Hemisphere storms spin counter clockwise
S. Hemisphere storms spin clockwise

16. In which hemisphere is this hurricane occurring?
Northern Hemisphere, it’s spinning is counter clockwise

17. This curving of the wind is called the Coriolis Effect
Does it affect the spinning of the water in my toilet?
No, the water in the toilet in not a large enough body of water.
Coriolis Effect on toilets?

18. All add together to create distinct wind patterns on Earth.
Earth’s surface with different surface materials (land or water)
Plus, the different amount of solar radiation received (direct or indirect light, and hours of light)
Plus, the Coriolis effect
All add together to create distinct wind patterns on Earth.

19. Common Wind patterns Polar Easterlies Westerlies Tradewinds Doldrums
Global winds over a year

21. Trade Winds were important to early explorers and for trade routes

22. Jet Stream A strong belt of wind in the upper troposphere.
It flows from west to east.
Pilots take advantage of this when they fly to the East coast.

23. The jet stream is why we look to the west to find out what type of weather is moving our way.

24. Local Wind Systems
Local areas near bodies of water experience smaller scale wind patterns

25. Sea breeze During the day, air over the land is heated by conduction.
The warmer, less dense air rises
The cooler (high pressure) ocean air moves into the low pressure area, resulting in a sea breeze

26. Land breeze At night, air over the land cools quickly.
The cooler, less dense (high pressure) sinks and moves towards the low pressure (warmer) air over the water.
Resulting in a land breeze.

27. Summary Warm air is less dense than cool air
Differences in density (temperature) and air pressure cause air movement- wind
Coriolis effect causes the wind to turn
Wind patterns are observed in different lattitudes
A wind pattern seen high in the troposphere is the jet stream
Sea breezes and land breezes are patterns of air seen near bodies of water.

28. Review Videos https://www.youtube.com/watch?v=RzSqhrn2dDM
Review of Wind
A visualization of global weather conditions forecast by supercomputers updated every three hours (open in Google Chrome) You can spin the globe and zoom in
The Sun as the driving force behind for wind and water currents and earth’s temperatures