14-4 Movement of Air Wind – caused by the uneven heating of Earth’s atmosphere. *heats unevenly due to its tilt and curved surface *difference in pressure – warm air rises, cold air sinks *AIR MOVES FROM HIGH PRESSURE TO LOW PRESSURE! Where is the air on Earth heated the most? Least? Why?

The Coriolis Effect Caused by Earth’s rotation Deflects all free moving objects to the right, north of the equator To the left, south of the equator Ex; air, water, rockets Think of a merry-go-round and throwing a ball from it

Planetary Wind Systems Doldrums – windless zone at the equator Hot air rises straight up No horizontal movement Sailors got stuck here Trade winds – between equator & 30 degrees N&S latitude In n. hemisphere they blow sw In s. hemisphere they blow nw Horizontal winds, good sailing

Planetary Wind Systems Con’t. Horse latitudes – approx. 30 degrees N& S of the equator Air has cooled, stops moving towards the poles and sinks No horizontal movement, windless zone Sailors got stuck, threw horses off ships, some say they ate the horses

Wind Systems con’t Prevailing westerlies- Between 30&60 degrees N&S latitude Responsible for much of US & Canada’s weather Blow from sw to ne in n. hemisphere Polar easterlies -60 degrees N&S latitude to the poles Blow from the ne to sw near the North Pole

Other Winds on Earth Jet stream – narrow belts of strong winds Near the top of the troposphere 2 in each hemisphere, blow west to east Latitude and altitude change Jet streams affect our weather Bring cold weather when they drop down in latitude

Other Winds Con’t. Sea breezes – wind blowing from sea to land Happens during the day Land warms faster than water, heating air over it by conduction Warm air rises, allowing cool air from over the water to move in, thus creating the wind

Other winds Con’t Land breezes – winds traveling from the land to the sea At night, land cools faster than water Warm air over the water rises Cool air over the land moves out over the water This creates a wind from the land to the sea