Wind Systems

Wind

· Produced by differences in air pressure

· Pressure difference between a high/low pressure area determines strength of wind

o Larger differences= stronger winds

Coriolis Effect

· Apparent force resulting from

Earth’s rotation eastward

· Causes things to be turned westward

· In Northern Hemisphere it pushes winds to the right; in Southern Hemisphere it pushes winds to the left

· On Earth this happens but in space, astronauts would still see air mass moving straight

Major Wind Systems

Doldrums

· Windless zone at the equator; appear to be motionless but air is being forced up

Trade Winds

· 30º Latitude

· Blow toward equator doldrums then rise

o In NH Blow NE to SW

o In SH blow SE to NW

· Good for ships and pilots going west

Prevailing Westerlies

· 30º to 60º in Latitude

· In US and Canada: winds are responsible for movement of weather

o NH: SW to NE

o SH: NW to SE

Polar Easterlies

· Cold, dry, dense air mass that descend at poles and flow outward

· Contribute large amounts of energy to westerlies

· 60º in Latitude

Jet Streams

· Discovered by American Pilots

· Flow west to east

· Form where warm tropics meets cold pole air

· Wind speeds: 120km/hr to 450 km/hr

· Constantly changing (not always in same location)