1. EQ: How is heat transferred through the layers of the Earth’s atmosphere? WIND

2. Whooosh!!!!!
When you open the valve on a bicycle tube, the air rushes out.
Why?
The air inside the tube is at a higher pressure than the air outside the tube.
This is similar to how winds are formed!

3. Unequal Heating
The movement of air caused by differences in air pressure is called wind
The greater the pressure difference, the faster the wind moves.
Wind is the result of a convection current

4. Unequal Heating
Differences in air pressure are generally due to the unequal heating of the earth.
Remember, warm air is less dense and will rise.
Cool air is more dense and sinks

5. Unequal Heating
The equator receives more direct solar energy (radiant heating) than other latitudes, so air at the equator is warmer and less dense than the surrounding air.
Lighter, one blanket
Warm, less dense air rises and creates an area of low pressure.
This warm, rising air flows toward the poles.

6. Unequal Heating
However, at the poles, the air is colder and denser than the surrounding air, so it sinks.
Heavier, many blankets
This sinking air creates an area of high pressure around the poles
This cold polar air then flows toward the equator

7. Air blows from high to low!!
Low Pressure
High Pressure
Rising, warmer air
Moist: Clouds, rain, snow, strong winds, warmer air
Snow means low!
Sinking, colder air
Dry: Clear skies, sunshine, cool air, little wind
High and Dry!

8. Pressure Belts
You may imagine that wind moves in one huge, circular pattern from the poles to the equator.
In fact, air travels in many large circular patterns called convection cells
Convection = circulation (moving air)
These convection cells are separated by pressure belts, which are bands of high or low pressure.
These belts are found about every 30* latitude

9. Pressure Belts

10. Pressure Belts
As warm air rises over the equator and moves toward the poles, the air begins to cool.
At about 30* North and 30*South latitude, some of this cool air begins to sink

11. Pressure Belts
This cool sinking air, causes high pressure around 30* N and S latitude.
This cooled air flows back to the equator, where it warms again, and rises.

12. And the same thing is happening at the poles, just in reverse
At the poles, the cold air sinks, and moves toward the equator.
The air warms as it moves toward the equator.
Around 60* N and S latitude, the warmer air rises, which creates a low pressure belt.
This air then flows back to the poles

13. The Coriolis Effect
Pressure differences cause the air to move between the equator and the poles.
But due to the earth’s rotation, the air does not move in straight lines!
This apparent curving of the path of winds is called the Coriolis Effect.

14. Coriolis Effect
Because of the Coriolis Effect, winds traveling north in the Northern Hemisphere appear to curve to the east, and winds traveling south curve to the west.
How would the Southern Hemisphere compare?

15. https://www. schooltube

16. Global Winds
EQ: How is heat transferred through the layers of the Earth’s atm0shere?

17. Global Winds
The combination of convection cells found at every 30* latitude and the Coriolis Effect produces patterns of air circulation called Global Winds.
The major global wind systems are the Polar Easterlies, Westerlies, and Trade Winds.
Winds such as the Easterlies and Westerlies are named for the direction from which they blow

18. Polar Easterlies
The wind belts that extend from the poles toward 60° N and S latitude.
They are formed when cold, sinking air (high pressure)
Polar Easterlies can carry cold, arctic air over the US, producing snow and freezing weather

19. Westerlies The wind belts found between 30° and 60° latitude.
They flow toward the poles from west to east.
Can carry moist air, producing rain or snow (low pressure)
Responsible for our weather

20. Trade Winds
Winds that blow from 30 degrees latitude almost to the equator are the trade winds.
Named after their ability to quickly propel ships across the ocean
They are warm, steady breezes that blow almost continuously(11-13 mph) (low pressure).
The Coriolis Effect makes the trade winds appear to be curving to the west in the Northern Hemisphere

21. The Doldrums
The trade winds of the N and S hemispheres meet in an area around the equator called the doldrums.
There is very little wind and the area is calm because the warm rising air creates an area of low pressure.
Doldrums means “dull” or “sluggish”

22. Coriolis Effect
The Earth’s rotation causes wind and surface currents to move in curved paths rather than in straight lines.
The apparent curving of moving objects from a straight path due to the Earth’s rotation is called the Coriolis effect.

23. The Horse Latitudes http://www.purposegames.com/game/global-winds-game
At about 30 degrees N and S latitude between the trade winds and prevailing westerlies
The winds at these locations are weak.
Most of the world’s largest deserts are located here because the sinking air is very dry
Weather is usually calm

24. Term from sailing ships that were stuck due to calm winds for long periods of time
due to shortages of food and water horses would die and be thrown overboard

25. Jets Streams
Jet streams are narrow belts of high-speed winds that blow in the upper troposphere and lower stratosphere.
They can blow as fast as 400 km/hr
They do not follow regular paths around the earth.
They help pilots and meteorologists

26. Local Winds
Local winds generally move short distances and can blow from any direction.
Local geographic features, such as a shoreline or a mountain can produce temperature differences that can cause local winds

27. Mountain and Valley Breezes

28. Sea Breezes http://www.youtube.com/watch?v=gM0d3fGew-0&feature=related