1. Do Now For Monday, October 22, 2012 Imagine you are flying from Seattle to San Francisco which is almost exactly due south of Seattle. Should the pilot set a course due south? Explain your answer. OR! How are local and global winds similar and how are they different?

2. Guided Notes For Chapter 3 Section 3 Winds! Wind = The horizontal movement of air from an area of higher pressure to an area of lower pressure.

3. All winds are caused by differences in air pressure and by unequal heating and cooling of the atmosphere (convection currents). High pressure replaces low pressure and winds are created.

4. Cooler, denser air flows underneath warm, less dense air – forcing it to rise and causing wind! *

5. Wind is measured by direction and speed. A south wind blows from south to north. West winds blow from west to east. Wind/Weather Vane measures wind direction.

6. Wind speed is measured with a anemometer. Greatest wind speed ever recorded 370 km/hr! (220 mi/hr)! Anemometer =

7. Wind Chill is cold wind blowing over your skin removing body heat. Intensifies the cold temperature. 20 0 F with 30 mph wind feels like -18 0 F. I DOUBLE DOG DARE YOU!

8. Local Winds blow over Earth’s surface within a small area. Always cool air replacing warm air rising. Sea Breeze = From ocean or lake to land. Land Breeze = From land to ocean or lake.

9. Monsoons occur seasonally in Southeast Asia. Summer Monsoons are sea breezes bringing lots of rain needed for crop growth. Winter Monsoons are land breezes blowing from land to sea.

10. GLOBAL WINDS blow over long directions and are also created by unequal heating of Earth’s surface over large areas. *

11. Global convection currents create the movement of air between the equator and poles causing regular wind patterns. *

12. CORIOLIS EFFECT – Named after French mathematician Gaspard Coriolis in 1835. *

13. Without Earth’s rotation, wind would blow in a straight line from the poles toward the equator. *

14. Rotation causes winds to curve. In the Northern Hemisphere, winds turn right and in the Southern Hemisphere, winds turn left. *

15. The Coriolis Effect creates calm areas and convection current wind belts around the Earth. GLOBAL WIND PATTERNS! Trade Winds, Prevailing Westerlies and Polar Easterlies are Global Winds.

16. In between the Global Winds are the Doldrums and Horse Latitudes. *

17. The doldrums are an area of rapidly rising warm air near the equator. The cool air replacing this is rapidly warmed and no wind is produced. Sailing ships were often stuck for months in the doldrums!

18. 30 0 North and South of the equator are the Horse Latitudes. Again, no wind as belts of air moving in opposite directions cause a calm spot here. *

19. TRADE WINDS are created as cold air from horse latitudes pushes air (wind) towards the equator. North Hemisphere trade winds blow from North East and South Hemisphere trade winds blow from South East. *

20. Prevailing Westerlies are mid latitude winds that blow west to east in both northern and southern hemispheres. Great effect on US weather! *

21. Polar Easterlies – Convection currents and the Coriolis Effect cause cold polar air to sink and create east to west winds. Great effect on US weather! *

22. Jet Streams are found 10 km above Earth and can be hundreds of km wide but only a few km deep. These winds blow from west to east at 200 – 400 km/hr. Jet stream winds have a great effect on our weather and help save fuel and time when traveling from west to east. *

23. Ad this to your notes! The Gulf Stream is a warm ocean current that begins in the Gulf of Mexico and travels north along the east coast of the US before crossing the Atlantic. The Gulf stream has a great impact on weather in the United States! What would happen if the Gulf Stream stopped?