2.3 Winds

1. 2.3 Winds P3 Blue

2. What causes wind? • What are local winds and global winds? How do they differ? • Where are the major global wind belts located? • Checkpoint: Toward what direction does a west wind blow? • Checkpoint: What happens to a wind blowing toward the south in the Northern Hemisphere? What would you call this wind? • Checkpoint: In what region do the polar easterlies meet the prevailing westerlies?

3. WhatCausesWind - Jake Air is a fluid so it can easily move place to place Air moves because the change of air pressure Air over a heated area expands and becomes less dense The cool dense air has a higher so it flows under the warm air

4. Measuring Wind • Wind is described by direction and speed • Direction is determined by a wind vane • Points in the direction the wind is blowing • Speed is measured with an anemometer • Coups mounted to a spinning axil, speedometer is used • Wind-chill factor is the increased cooling caused by wind

5. Local Winds • Local winds are winds that blow over short distances. • Local winds are caused by unequal heating of Earth’s surface within a small area. • Form only when no winds are blowing form further away • Sea breeze or lake breeze – wind blows from the body of water onto land. • Land breeze – wind blows from land to a body fo water.

6. Monsoons - Amber • Monsoons are sea and land breezes over a large region that change direction with the seasons. • Air blowing from the ocean during the rainy season is very warm and humid. • As the humid air rises over the land, the air cools, producing heavy rain.

7. Global Winds - Alexa *GLOBAL WINDS= winds that blow steadily from specific directions over long distances What produces global winds? Answer: the movement of air between equator and the poles *CORIOLIS EFFECT= the way earths rotation makes wind curve Northern Hemisphere= global wind curves to right Southern Hemisphere= global wind curves to left

8. Global Convection Currents • The movement of air between the equator and the poles produces global winds. • Giant convection currents in the atmosphere are due to the temperature differences between the poles and the equator. • Equator – lower pressure • Poles – higher pressure

9. What is the Coriolis Effect? - Anna • The way Earth’s rotation makes winds curve. If the Earth didn’t rotate, global winds would blow in a straight line toward the equator. As the winds move, Earth rotates from west to east underneath, making it seem like the winds have curved. In the Northern Hemisphere winds turn to the right, while in the Southern Hemisphere winds turn to the left.

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11. Global Wind Belts • Major Global Wind Belts • Doldrums • Horse Latitudes • Trade Winds

12. Doldrums - By Isabella Macleod • Regions near the equator with little or no wind is called the doldrums • Near the equator the sun heats the surface, warm air rises and creates an area of low pressure. Cool air comes but is heated and rises into the air. The wind near the equator is weak because there is a very little horizontal motion.

14. Horse Latitudes - Josh de la Rivera • Warm air rises at the equator and flows North and South • Near 30° North and South latitudes is where air stops moving to the poles and sinks • Hundreds of years ago, sailors were running out of food and water so they through there horses overboard which later gave the horse latitudes their name

15. Trade winds - Charlie when cold air over the horse latitudes sinks it produces a region of high pressure It causes surface winds that blow towards and away from the equator Winds that fly towards the equator are shot west with the Corioliseffect Winds in the north hemisphere between 30 degrees north latitude and the equator blow from the northeast and from the southern hemisphere they blow southeast For many years sailors have used these winds to carry cargo from Europe to America

16. EXPLORING GLOBAL WINDS The prevailing westerlies blow away from the horse latitudes. A series of wind belts circles Earth. Between the belts are calm areas where air is rising or falling. POLAR HIGH PRESSURE ZONE POLAR EASTERLIES 60 SUB POLAR LOW The trade winds blow from the horse latitudes toward the equator. WESTERLIES SUB TROPIC HIGH 30 TRADEWINDS DOLDRUMS 0 The doldrums are a calm area where warm air rises. TRADEWINDS HORSE LATITUDES 30 WESTERLIES 60 POLAR EASTERLIES AT HIGH AND LOW PRESSURE ZONES MOST AIR MOVEMENT IS VERTICAL, NOT HORIZONTAL. The cold polar easterlies blow away from the poles. The horse latitudes are calm areas of falling air. BY MANVI MALHOTRA

17. Prevailing Westerlies - Ava • They blow generally from the southwest between 30 and 60 degrees north latitudes. • From the Northwest between 30 and 60 degrees south latitudes. • The Prevailing westerlies play an important part in the weather of the United States.

18. Polar Esterlies • Shifting of polar winds to the west • Meet the prevailing westerlies at 60◦ north and 60◦ south latitudes • Polar front • Mixing of cold and warm air at the polar front effects weather changes in the US

19. Jet Streams Gaby Highton Jet streams are about 10km above Earth’s surface and are bands of high speed winds. Blow from east to west at speeds of 200 to 400km per hour. Helps airplanes when traveling east because it moves the airplane faster so pilots use less fuel.

20. Self Quiz – Can you answer these? • What causes wind? • What are local winds and global winds? How do they differ? • Where are the major global wind belts located?