1. Global and Local Winds

2. Air Movement
Wind is the horizontal movement of air from high pressure to low pressure. It is caused by differences in air pressure
The greater the difference, the faster the wind moves

3. Air Pressure
Differences in air pressure are caused by the uneven heating of Earth
Cool, denser air with a higher pressure flows underneath the warm, less dense air. This forces the warm air to rise.

4. Wind Vane- measures wind direction
Wind Vane- measures wind direction.- tells you where the wind is coming from. Ex: a north wind comes FROM the north.
Barometer- measures air pressure
Anemometer- measures wind speed.
Wind chill factor- the increased cooling a wind causes.

5. Wind Chill
Why does a cool breeze feel refreshing in the summer, but cold in the winter?
Wind blowing over your skin removes body heat. The stronger the wind, the colder you feel.

6. Local Winds
Generally move short distances and can blow in any direction
Caused by geographic features that produce temperature differences
Caused by the unequal heating of Earth’s surface within a small area.

7. It takes more energy to warm up and cool down a body of water than it does to warm up land.
Wherever the cool air is located, that is the type of breeze. Ex: sea breeze- cool air is over the sea.

8. Sea Breezes
High pressure is created over the ocean (cooler air) during the day and low pressure (warmer air) over land due to uneven heating
Air moves from the ocean to the land creating a sea breeze

9. A. Sea Breeze Happens during the day.
Land warms up faster than the water.
Air over the land becomes warmer than air over the water.
The warm air expands and rises, creating a low-pressure area.
Cool air blows inland from over the water and moves underneath the warm air, causing a sea breeze.
Sea Breezes blow FROM THE SEA.

10. Sea Breeze

12. Land Breezes
Low pressure occurs over the ocean during the night and high pressure over land due to the uneven heating of earth
This causes wind to move from the land to the ocean creating a land breeze

13. B. Land Breeze 1.Happens at night. Land cools more quickly than water.
Air over the land becomes cooler than air over the water.
Warmer air over the water expands and rises.
Cooler air from land moves beneath it.
Land Breezes blow FROM THE LAND.

14. Land Breeze

16. Sea and Land Breeze animation

17. Question 1
What causes winds?

18. Answer
Winds are caused by the uneven heating of Earth’s surface, which causes pressure differences

19. Teach Time
Teach your neighbor about land and sea breezes.

20. Pressure Belts
Uneven heating produces pressure belts which occur every 30° latitude

22. As warm air rises at the equator and moves toward the poles, it cools
Pressure Belts
As warm air rises at the equator and moves toward the poles, it cools
As it cools, some of the air sinks around 30° north and south of the equator

23. At the poles, cold air sinks and moves towards the equator
Pressure Belts
At the poles, cold air sinks and moves towards the equator
Around 60° north and south, the air begins to heat up and rise

24. A. Coriolis Effect
As the winds blow, Earth rotates from West to East underneath them, making it seem as if winds are curving.
Global winds in N. Hemisphere turn toward right.
S. Hemisphere, winds curve toward left.

25. These are polar easterlies, westerlies, and trade winds
Global Winds
The combination of pressure belts and the Coriolis Effect cause global winds
These are polar easterlies, westerlies, and trade winds

26. Global Winds
Winds that blow steadily from specific directions over long distances.
Created by the unequal heating of Earth’s surface.
Near the equator, sun’s rays strike earth directly. Near the poles, sun’s rays do not strike Earths’ surface directly.
The sun’s energy is spread out over a larger area, so it heats the surface less. Therefore, temps. Near the poles are lower than near the equator.

27. 5. Temp. differences btwn equator and poles create giant convection currents, movements of air between the equator and poles.
6. Warm air rises at the equator and cold air sinks at the poles.
7. Air pressure tends to be lower near the equator and greater near the poles.
Winds at the surface blow from poles toward equator. High in the atmosphere, air flows away from the equator toward the poles.
They curve because of Earth’s rotation.

29. Wind belts that extend from the poles to 60° latitude
Polar Easterlies
Wind belts that extend from the poles to 60° latitude
Formed from cold sinking air moving from the poles creating cold temperatures

30. E. Polar Easterlies
Cold air near poles sinks and flow back toward lower latitudes (away from the poles).
Mixing of warm and cold air along the polar front has major effect on weather in US.

32. Wind belts found between 30° and 60° latitude
Westerlies
Wind belts found between 30° and 60° latitude
Flow towards the poles from west to east carrying moist air over the Unites States

33. D. Prevailing Westerlies
mid-latitudes, btwn 30 and 60 North and South, winds blow toward poles are turned toward the east by Coriolis effect.
Winds blow west to east.
PLAY IMPORTANT ROLE IN WEATHER IN USA.

35. Winds that blow from 30° almost to the equator
Trade Winds
Winds that blow from 30° almost to the equator
Called the trade winds because of their use by early sailors

36. C. Trade Winds
Cold air over horse latitudes causes high pressure when it sinks.
High pressure causes surface winds to blow toward equator and away from it.
Winds that blow toward equator are turned west by Coriolis effect.
Winds are high and they help ships get across the ocean.
In the Northern Hemisphere, they move from the NE. In the Southern Hemisphere, they move from the SE.

38. Doldrums
Located along the equator where no winds blow because the warm rising air creates and area of low pressure

39. A. Doldrums
Near equator, sun heats surface strongly. Warm air rises, creating low pressure.
Cool air moves into area, but is warmed rapidly and rises before it moves very far.
Little or no wind there (very calm)

40. B. Horse Latitudes
Warm air rises at equator and flows both north and south.
At 30 degrees north and south, air stops moving toward poles and sinks.
Calm air is here.

41. Most deserts on the Earth are located here because of the dry air
Horse Latitudes
Occur at about 30° north and south of the equator where the winds are very weak
Most deserts on the Earth are located here because of the dry air

42. Separates warm air from cold air
Jet Stream
The jet streams are narrow belts of high speed winds that blow in the upper troposphere and lower stratosphere
Separates warm air from cold air

43. F. Jet Streams
Bands of high-speed winds about 10km above Earth’s surface.
They are hundreds of km wide but only a few km deep.
Jet streams blow from west to east at speeds of km/hr.

45. What are the three types of global winds?
Question 2
What are the three types of global winds?

46. Answer
Polar Easterlies
Westerlies
Trade Winds

47. What is the difference between a land breeze and a sea breeze?
Question 3
What is the difference between a land breeze and a sea breeze?

48. Answer
Sea breezes occur during the day when the land is warmer than water and a land breeze occurs at night when the water is warmer than land

51. Bill Nye
– Wind - Atmosphere

52. Mr. Parr Winds Blow