1. 15-3 Atmospheric Pressure and Winds pgs. 402-407 IN: What causes winds?

2. Terms to Learn and Objectives
Wind Coriolis effect trade winds westerlies polar easterlies jet streams
Objectives:
Explain the relationship between air pressure and wind direction.
Describe the global patterns of wind.
Explain the causes of local wind patterns.

3. Wind is moving air created by differences in air pressure.
The greater the pressure difference, the faster the wind moves.

4. Pressure Belts –
As warm air rises over the equator, it begins to cool and begins to sink causing a high-pressure belt
At the poles, cold air sinks and moves away along the surface. As it warms, it begins to rise causing low-pressure belt

5. Pressure Belts

6. The rotation of the earth causes the Coriolis Effect which causes wind to travel in a curved path rather than a straight line.

7. Types of Winds
Local winds move short distances and can blow from any direction
Global winds are part of a pattern of air circulation that moves in a specific direction across the Earth.

8. Trade Winds – the wind that blows in both hemispheres from 30° latitude to the equator

9. Doldrums are an area of low pressure around the equator where the trade winds of both hemispheres meet.
Horse latitudes are an area of high pressure at about 30° north and south caused by sinking air.

10. Westerlies are wind belts found in both hemispheres between 30° and 60° latitude and flow toward the poles in the opposite direction of the trade winds.

11. Polar Easterlies are wind belts formed from cold, sinking air that extend from the poles to 60° latitude in both hemispheres.

12. Jet Streams are narrow belts of wind that blow in the upper troposphere and lower stratosphere. They may reach speeds of 500 km/h and do not follow regular paths.

13. Local winds are influenced by the geography of an area.
Areas such as shorelines and mountains sometimes produce temperature differences that cause winds

15. Question 1
What causes winds?

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

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

18. Answer
Polar Easterlies
Westerlies
Trade Winds

19. 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?

20. 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