Global Wind Patterns

1. Global Wind Patterns

2. What is Wind? • Wind is the movement of air from an area of higherpressure to an area of lowerpressure. Warmer air expands, becoming less dense than colder air. This causes air pressure to be generally lower where air is heated.

3. The CoriolisEffect • Coriolis Effect – Rotation of the Earth causes moving air and water to change directions • Northern Hemisphere winds curve to the right • Southern Hemisphere winds curve to the left. http www.youtube.com/watch?v=mcPs_OdQOYU

5. The CoriolisEffect - The tendency for any moving body on or above the earth's surface, such as an air or water current, to drift sideways from its course because of the earth's rotation. This affects Earth’s winds and water movement. Air moves to the right in the Northern Hemisphere. In the Southern Hemisphere, they move to the left.

7. 90 Warm Moist Air Rises 60 30 0 30 60

8. 90 Cool Dry Air Sinks Warm Moist Air Rises Cool Dry Air Sinks 60 30 0 30 60

9. 90 Cool Dry Air Sinks Warm Moist Air Rises Cool Dry Air Sinks 60 30 0 30 60 Cold Moist Air Rises Cold Moist Air Rises

10. 90 Cool Dry Air Sinks Warm Moist Air Rises Cool Dry Air Sinks 60 30 0 30 60 Very Cold Air Sinks Cold Moist Air Rises Cold Moist Air Rises Very Cold Air Sinks

11. H L 90 H Cool Dry Air Sinks Warm Moist Air Rises L Cool Dry Air Sinks 60 H L H 30 0 30 60 Very Cold Air Sinks Cold Moist Air Rises Cold Moist Air Rises Very Cold Air Sinks

12. H L 90 H L 60 H L H 30 0 30 60 Wind Moves from HIGH to LOW

13. 90 60 30 0 30 60 Objects are deflected to the RIGHT in the Northern Hemisphere

14. Global Winds • Global Winds - Wind gets its name from the direction it is blowing FROM!

20. Winds in the Upper Troposphere • The jet stream is a current of fast moving air found in the upper levels of the troposphere.

21. Jet Stream • Discovered in 1940’s • Can be found in the upper troposphere • Strong high speed and high pressure • Moves west to east across the US, moving storms

22. The polar jet stream forms at the boundary of cold, dry polar air to the north and warmer, more moist tropical air to the south.

23. What brings certain weather phenomenon?

24. GLOBAL FORCES • The following global forces can affect the formation of surface currents.

25. Continental Deflection Global Forces Equator Earth’s Rotation

26. Continental Deflection Since the Earth’s surface is not fully covered by water, currents cannot move freely around the world. So when surface currents meet continents, they deflect, or change direction. 2 1 3 Predict what will happen with each labeled area.

27. Continental Deflection Global Forces Coriolis Effect Equator Earth’s Rotation

28. North Pole Earth’s Rotation Coriolis Effect The Earth’s rotation causes surface currents to move in curved paths rather than in a straight line.

29. Continental Deflection Global Winds Global Forces Coriolis Effect Equator Earth’s Rotation

30. Global Winds Global winds are affected by their latitude and the Coriolis Effect. In the tropics winds blow from the east to the west. In more temperate areas, the winds blow from the west to the east. Near the poles the winds blow from the east to the west. Polar Easterlies Westerlies Tradewinds Tradewinds Westerlies Polar Easterlies

31. Continental Deflection Global Winds Global Forces Transparency Coriolis Effect Deep Ocean Currents Equator Earth’s Rotation

32. Deep Ocean Currents • Deep cold currents move water toward the equator. • Cold water rises to replace warm water leaving. • Warm water travels near the surface toward polar regions. • Warm water replaces cold water.

33. Global Forces Continental Deflection Since the Earth’s surface is not fully covered by water, currents cannot move freely around the world. So when surface currents meet continents, they deflect, or change direction. Global Winds Global winds are affected by their latitude and the Coriolis Effect. In the tropics winds blow from the east to the west. In more temperate areas, the winds blow from the west to the east. Near the poles the winds blow from the east to the west. Coriolis Effect The Earth’s rotation causes surface currents to move in curved paths rather than in a straight line. Deep Ocean Currents Deep cold currents move water toward the equator. Cold water rises to replace warm water leaving. Warm water travels near the surface toward polar regions. Warm water replaces cold water. Equator Earth’s Rotation