1. Please take out your Skills WS and check your work with a desk partner. Be ready to ask any questions on 15.2.

2. 15.3 Global Winds and Local Winds Copy into your IAN! Objectives: 1.Explain the relationship between air pressure and wind direction. 2.Describe global wind patterns. 3.Explain the causes of local wind patterns.

3. Why Air Moves  Wind-movement of air caused by differences in air pressure  Greater pressure difference=faster wind

4. Air Rises at the Equator and Sinks at the Poles  Differences in air pressure are generally caused by unequal heating of the Earth.  Equator  Receives more direct solar energy  Air is warmer and less dense  Warm air rises and creates low pressure area  Warm air flows to poles

5. National geographic video clip  http://video.nationalgeographic.com/vid eo/player/science/earth-sci/weather-101- sci.html?referrer=epals

6. Air Rises at the Equator and Air Sinks at the Poles, cont’d  Poles  Air is cooler and more dense  Cold air sinks  Creates high pressure area  Cold air flows toward equator  AIR Moves from H to L !!!

7. Pressure Belts Are Found Every 30 Degrees  Pressure belts-bands of high pressure and low pressure found every 30 latitude.  Sinking air causes areas of high pressure because sinking air presses down on the air beneath it.

9. The Coriolis Effect  Apparent curving of the path of winds and ocean currents due to the Earth’s rotation.  North- winds going north curve east  South- winds going south curve west

10. Global Winds  Patterns of air circulation  Named from direction from which they blow  Major global wind systems  Polar easterlies  Prevailing Westerlies  Trade winds

11. Global winds

13. Polar Easterlies  Poles to 60 latitude in both hemispheres  Cold, dense air moves from poles to 60  Can bring cold air to US making snow and freezing weather

14. Prevailing Westerlies  30 and 60 latitude in both hemispheres  Flow from west to east  Can bring moist air to US making rain and snow

15. Trade Winds  30 latitude almost to equator in both hemispheres  Due to Coriolis-curve to west in N. Hemisphere and east in S. Hemisphere  Traders used winds to move from Europe to Americas.

16. Doldrums located where the trade winds of the two hemispheres meet at the equator means “dull” or “sluggish” an area of Low pressure

17. The Horse Latitudes  30 north and south latitude  Very weak winds

18. Jet Stream: Atmospheric Conveyor Belts  Narrow belts of high speed winds  Blow in the upper troposphere and lower stratosphere  Can affect movement of storms and airplane flights

19. Local Winds  Move short distances  Blow from any direction  Caused by temperature differences  Sea breeze moves from sea to land  Land breeze moves from land to sea

21. How does wind blow?  Wind will flow from high to low!!!

22. Wrapping it up  What role does the Sun play?  Sun heats the land and water, changing temperatures  Different heating causes density differences, causing wind!  UNEQUAL HEATING CAUSES THE WIND!

23. Temperature of Coast vs. Inland  Avg temperature Atlanta: low-23 to 51: 28 degree difference for January  Avg temp. for Savannah: low-38 to 60: 22 degree difference  Avg for July: Atlanta-88  Savannah- 92  Why is Savannah warmer?  Gulf Stream runs by it and there is a constant breeze blowing near the ocean  Lower temp range on coast

24. Sea Breeze (Draw your own picture)

26. Temperature of Coast vs. Inland  Coastal areas don’t get as warm or as cold as inland areas because it has the ocean to moderate their temperatures.

27. Land Breeze (draw your own picture here)

29. Mountain Breeze vs,. Valley Breeze