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Wind
Horizontal movement of air
Movement due to:
High pressure into Low pressure
Caused by:
Temperature changes
Humidity changes
Direction
 Winds are labeled by where they originate – North wind is from the North
blowing south
 Wind vane measures direction results given in degrees 0-360
Speed
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Measured with cup anemometer
Local winds
Sea/Land Breezes
Out to sea during the day
Into shore during the night
Caused by uneven heating of the Earth
Mountain/Valley Breezes
Up the mountain during the day
Down the mountain during the night
Caused by warming and cooling of the air
Chinook and Santa Ana winds
 winds descend down the leeward side of a mountain warming by
compression
 Dry air that may be 10-40 degrees warmer than current air
 Santa Ana winds occur in California and may bring dry warm air to forest
fires -- decreasing chance of putting them out
Surface High Pressure Areas and Low Pressure
Center of High pressure
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Pressure increases towards the center
Air moves outwards ( Divergence ) being replace by air from above -sinking air
Usually brings stable “fair” weather
Shift to the right in Northern Hemisphere causes wind to spin clockwise 
“Anticyclone”
Counterclockwise in the Southern Hemisphere
Center of Low pressure
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Pressure decreases toward the center
Air moves inwards (Convergence ) forcing air to go up to allow for more
air -- rising air
Usually brings clouds and precipitation
Shift to the right in Northern Hemisphere causes wind to spin
counterclockwise  “Cyclone”
Clockwise in the Southern Hemisphere
Global Wind Patterns
1. Without a spinning Earth or Continents Warm air would rise and move towards the poles,
replaced by cooler air from the poles creating one large convection current for the Northern
Hemisphere and one for the Southern Hemisphere
2. This would cause surface winds towards the Equator
3. Spinning Earth creates the Coriolis effect
Apparent deflection of wind due to Earth’s spin
To the right in the Northern Hemisphere
To the left in the Southern Hemisphere
ONLY affects large masses DOES NOT affect toilet drains enough to change spin!
Along with uneven heating of Oceans and Land this Creates 3 convection cells in each
hemisphere = 6 cells
1. Equatorial Low pressure zone
a. Rising air
b. Abundant precipitation
2. Subtropical High pressure zone
a. Sinking dry air
b. Near 30 degree Latitude
c. Location of Great Deserts
d. Produces trade winds as air moves towards the Equator
e. Produces westerly winds as air moves towards the Poles
3. Subpolar Low pressure zone
a. Warm an dcool winds interact
b. Polar front – stormy
4. Polar High pressure zone
a. Cold sinking air
b. Air spreads towards the Equator producing Polar Easterlies
Friction
Slows down wind near Earth’s surface
Not important in the upper atmosphere
Upper Level winds
Flow parallel to isobars
Jet Stream  River of Air
Influence of Continents
Seasonal temperature differences disrupt Global wind patterns
Most obvious in Northern Hemisphere (compare amount of land in each hemisphere)
Monsoon
Seasonal change in wind direction
Warm months air flows onto land -- Brings RAIN
Cool months air flows off the land -- Dry Season
El Niño