Transcript Slide 1
Hour.3 By: Sam Hurwitz, Alex Payne, and Joey Peirick Global Winds Global winds are winds that blow steadily from specific directions over long distances. Like local winds, global winds are created by the unequal heating of Earth’s surface. But unlike local winds, global winds occur over a large area. Global Convention Currents • Warm air rises at the equator and the cold air • • sinks at the poles Global winds develop by temperature difference between the equator and the poles that produce giant convention currents in the atmosphere. This difference in pressure causes winds at Earth’s surface to blow from the poles toward the equator. The Coriolis Effect • The way Earth’s • rotation makes wind curve is called the Coriolis effect. Because of the Coriolis effect, global winds in the Northern Hemisphere gradually turn toward the right. Global Winds Belts • The major global wind belts are the trade winds, the polar easterlies, and the prevailing westerlies. • The calm air include the doldrums and the horse latitudes. Doldrums • Near the equator, the sun heats the surface strongly. • Cool air moves into the area, but is warmed rapidly and rises before it moves very far. • Regions near the equator with little or no winds are called Doldrums. Horse Latitudes • Latitude is the distance from the equator, measured in degrees. • Called Horse Latitudes because sailors would run out of water and food for the horses and had to throw them over board. Trade Winds • When the cold air over the horse latitudes sink, it produces a region of high pressure. • The high pressure causes surface winds to blow towards the equator. • It is called trade winds because sailors would use these to move ships carrying goods to different countries. Prevailing Westerlies • In the mid-latitudes between 30 and 60 degrees North and South, winds blow towards the poles turned east by the Coriolis effect. Polar Easterlies • Cold air near the poles sinks and flows back toward lower latitudes. • The mixing of warm and cold air along the polar front has a major effect on weather in the U.S Jet Streams • Jet streams are bands of high speed winds about 10 km. above the surface. • These winds are 100’s of km. wide, but only a few km. deep. • Jet streams usually flow from the west to the east at speeds of 200 to 400 kph.