Global WindsGlobal WindsChapter17Chapter17
Formation of WindFormation of Wind
warmer air = less dense = rising air warmer air = less dense = rising air
(lower pressure)(lower pressure) colder air = more dense = sinking air colder air = more dense = sinking air
(high pressure)(high pressure)
Global Wind
Where in the world would there be HIGH pressure?
poles
Where in the world would there be LOW pressure?
equator
HADLEY cells
Hot air rises; cold air sinks Vertical motion that causes global
wind
What direction to winds flow?
Wind flows from HIGH to LOW
Coriolis EffectCoriolis EffectEarth’s rotation causes wind to:Earth’s rotation causes wind to:curve to the right in the N. curve to the right in the N. Hemisphere ; left in the S. Hemisphere ; left in the S. HemisphereHemisphere
What is global wind?What is global wind?
-General -General movement of air movement of air worldwide due to pressure worldwide due to pressure differences at the equator and at differences at the equator and at the polesthe poles
-caused by temperature difference-caused by temperature difference
Three global wind beltsThree global wind belts
Trade windsTrade winds (0- (0-30˚)30˚)
blow from NEblow from NE Prevailing Prevailing
westerlieswesterlies (30-60˚) (30-60˚)• Blow from SWBlow from SW
Polar easterliesPolar easterlies (60-90 ˚)(60-90 ˚)• Blow from NEBlow from NE
RealityReality
Places without windPlaces without wind
Doldrums (equatorial low) Doldrums (equatorial low) - zone - zone near the equator O ˚near the equator O ˚
Horse latitudes (subtropical Horse latitudes (subtropical high)-high)-(30˚)(30˚)
Jet StreamJet Stream Bands of wind in upper troposphere/lower Bands of wind in upper troposphere/lower
stratospherestratosphere Blows from west to eastBlows from west to east North of JS= coldNorth of JS= cold Moves Pressure systems Moves Pressure systems
What causes wind?