air movement 15.3

CH. 15-3CH. 15-3Air MovementAir Movement

Forming WindForming Wind WindWind – the movement of air – the movement of air

from an area of higher from an area of higher pressure to an area of lower pressure to an area of lower pressure.pressure.

Air pressure is lower where Air pressure is lower where air is warmer.air is warmer.

Coriolis EffectCoriolis Effect The rotation of the Earth that The rotation of the Earth that

causes moving air and water causes moving air and water to appear to turn to the right to appear to turn to the right in the northern hemisphere & in the northern hemisphere & to the left in the southern to the left in the southern hemisphere.hemisphere.

Global WindsGlobal Winds Trade winds – winds created Trade winds – winds created

by air descending to Earth’s by air descending to Earth’s surface between the equator surface between the equator and 30and 30° latitude.° latitude.

Westerlies – winds formed Westerlies – winds formed between 30° & 60° latitude between 30° & 60° latitude that move weather systems in that move weather systems in the US.the US.

Winds in TroposphereWinds in TroposphereJet streamsJet streams – narrow belts – narrow belts

of strong wind that blow of strong wind that blow near the top of the near the top of the troposphere from west to troposphere from west to east.east.

Helps move storms across Helps move storms across the countrythe country

Winds in TroposphereWinds in TroposphereWhen flying eastward, jets When flying eastward, jets

save time & fuel.save time & fuel.When flying westward, When flying westward,

planes fly at different planes fly at different altitudes to avoid jet altitudes to avoid jet streams.streams.

Sea BreezesSea BreezesMovement of air from sea Movement of air from sea

to land during the day.to land during the day.Cooler air from above the Cooler air from above the

water moves over land, water moves over land, forcing the warm, less forcing the warm, less dense air above land to dense air above land to rise.rise.

Land BreezesLand Breezes The movement of air toward The movement of air toward

the water from land at nightthe water from land at night.. At night, land cools faster At night, land cools faster

than ocean water.than ocean water. Air over land becomes cooler Air over land becomes cooler

& moves over the ocean & moves over the ocean water.water.