“Air Pressure, Centers, & Wind”
19.1/19.2
Air Pressure
•	Weight of Air
•	All directions
•	Changes in pressure cause wind
•	Wind changes temperature & humidity

Barometer
•	Bar = pressure
•	Metron = measuring tool

Factors Affecting Wind
•	Pressure “Gradient” (differences)
•	Coriolis Effect
•	Friction

Pressure “Gradient”
•	Gradient = difference
•	Uneven heating from sun 
•	Air moves from Hp  Lp

Air Pressure
–	Measured in “Millibars”
•	Isobar
–	Line of same pressure!

•	Close Isobars
–	Fast wind
•	Far Isobars
–	Slow wind
•	Pressure Center
–	Bull's-eye (High/Low)
•	HP
–	Clear skies
–	Good weather
•	LP
–	Cloudy
–	Precipitation
•	Coriolis Effect
–	Changes wind direction
–	B_____ 
–	Earth’s R________