1. Winds
Chapter 2.3
Pages 52-60

2. What is Wind?
Wind- The horizontal movement of air from an area of high pressure to an area of lower pressure.

3. What causes winds? Winds are caused by differences in air pressure
The pressure differences are caused by unequal heating of the Earth’s atmosphere.

4. H L

5. What causes winds? H L More Dense air sinks Less Dense air rises
Has High Pressure
Less Dense air rises
Has Low Pressure H L

6. How is wind measured?
Weather Vane: an instrument used to determine the direction of the wind.
Anemometer: An instrument used to measure wind speed.

7. Anemometer
Cups blow in the wind and measure the speed of the wind.

8. Weather Vane Tells the direction the wind is blowing from.
If it is pointing to the south, wind is blowing from the south to the north.

9. Wind Chill
Wind Chill Factor: Wind blows over your body and removes body heat.
The stronger the wind, the more heat removed, the colder you feel.

10. Wind Chill What happens to the temperature as wind speed increases?
What is the wind chill if the temp is 5˚F and the wind is blowing at 25mph?

11. How do temperature and pressure cause wind?
Exit Pass
How do temperature and pressure cause wind?

12. Local Winds Winds that blow over short distances
Caused by unequal heating of Earth’s surface within a small area
Land heats faster than water
Water cools slower than land.

13. Local Winds Sea Breeze: The flow of air from a body of water to land H
Land is warmer, less dense air rises
Water is cooler, more dense air sinks. H L

14. Local Winds Land Breeze: The flow of air from land to a body of water
Water is warmer, less dense air rises
Land is cooler, more dense air sinks. L H

15. Monsoons
A large sea and land breeze over a large region that changes direction with the seasons.
Winds blow steadily from the land to the ocean, or the ocean to the land depending on the season.

16. Reading Wind Maps North Wind Direction West East South
Cloud Cover
Wind Direction
West
East
South
The line points into the weather station from the direction the wind came from.
This example shows that the wind is coming from the east.

17. Reading Wind Maps Wind Speed
Cloud Cover
Wind
Speed
To determine wind speed. Read the flag on the end of the wind direction line.
Use the chart to determine the wind speeds in knots and mph.
Example above: 8-12 knots (9-14mph)