1. Winds
Chapter 2 Section 3

2. What is Wind?
Wind is the horizontal movement of air from an area of high pressure to an area of low pressure.
Pretty simple huh?
How many kinds of winds are there? A bunch!

3. What Causes Wind? Simply put…
All wind is caused by a difference in air pressure.
So what causes the differences in air pressure?
The cause of differences in air pressure is the uneven heating of Earth’s surface.

4. How do we measure wind? Two ways:
Direction
Speed
Direction is measured by a wind vane.
Wind direction is the direction the wind is blowing from. So a west wind is blowing from the _______.
Speed is measured by an instrument called an anemometer.

5. Wind Chill Factor Increased cooling that wind causes
Mainly hear about it during the winter months
The stronger the wind the colder it makes you feel.
“The temperature will be 25 degrees, but the wind chill will make it feel like 15 degrees.”

6. Types of Winds
Yup, there are different types of wind.
Who knew right?

7. Local Winds
Caused by unequal heating of Earth’s surface within a small area
Common around large bodies of water
How many have been to the lake or beach and the wind is constantly blowing?
The surface between land and water are heated unevenly so you get a breeze.

8. Local Winds Sea Breeze Land Breeze
Flow of air from body of water to land
Occurs during the day
Land heats faster than water
Land Breeze
Flow of air from land to body of water
Occurs during the night
Land cools faster than water

9. Monsoons Monsoon is Arabic for “season”
Similar to land and sea breezes EXCEPT they occur over a large area
They change direction with the seasons
Occurs in South and Southeast Asia
Summer-blows towards the land 24/7 and brings rain
Winter- blows toward ocean 24/7

10. Global Winds
Winds that blow steadily from a specific direction over long distances
Again created by unequal heating of Earth’s surface

11. Global Convection Currents
Occurs because of the temperature differences at the poles and equator
Creates a giant convection current
Moves air from the equator to the poles

12. The Coriolis Effect
Earth’s rotation affects the way winds move from the poles to the equator
Because of Earth’s rotation the winds curve
Northern Hemisphere- winds turn toward the right
Southern Hemisphere- winds turn toward the left

13. Global Wind Belts Doldrums Horse Latitudes
Occur at and near the equator
Winds are either very weak or there is no wind at all
Horse Latitudes
About 30 degrees north and south
Air stops moving toward the poles and sinks
Another belt of calm air.
What might have happened hundreds of years ago with sailors in this area?

14. Trade Winds
Steady winds found between the equator and 30 degrees north and south latitude
Sailors relied upon these winds to carry cargo from Europe to West Indies and South America

15. Prevailing Westerlies
Northern hemisphere blow from the southwest at degrees north latitude
Southern hemisphere blow from the northwest at degrees south latitude
Play an important part in the US weather.

16. Polar Easterlies Cold air sinks and flows back to lower latitudes
These meet the prevailing westerlies

17. Jet Stream
About 10km above Earth’s surface are bands of high speed winds
Speeds are from km/hr
Can aid planes when traveling east.
Saves time and fuel
Hinders planes traveling west
Slows them down