Global & Local Winds
Wind
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Wind is created by differences in air pressure.
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The greater the pressure the faster the wind moves.
Equator: warmer less dense air rises and creates
an area of high pressure.
Poles: colder, more dense air sink & creates
areas of high pressure.
Air moves from high to low pressure (poles
to the equator)
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How does the Sun’s energy
produce wind?
The unequal heating of Earth by the sun causes
differences in air pressure. This causes convection
currents, which produce wind.
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Pressure Belts
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Equator: warm air rises & moves away & begins to cool,
at 30 degrees N & S latitude are high pressure belts.
Poles: cold air sinks & moves away & begins to
warm, creating a low pressure belt around 60
degrees N & S latitude.
Convection Cells: circular patterns caused by
the rising & sinking of air.
Coriolis Effect: the curving of moving objects,
such as wind, by the Earth’s rotation.
N. Hem. curves right S. Hem curves left
Two Types of Wind
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Local Winds: move short distances & can blow from any
direction.
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Global Winds: are part of a pattern of air circulation that
moves across the Earth (travel longer distances).
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Global winds include: trade winds, westerlies, & polar
easterlies.
More about the types of WIND!
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Trade winds: blows from 30 degrees
latitude to the equator. They meet in
an area of low pressure around the
equator called the doldrums (little wind
b/c of warm rising air).
About 30 degrees N and S. latitude, high
pressure (horse latitudes) winds are weak.
Westerlies & Easterlies
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Westerlies: found between 30 degrees &
60 degrees latitude. They flow toward the
poles in opposite direction of the trade
winds.
Polar Easterlies: cold, sinking air wind
belts that extend from the poles to 60
degrees N & S latitude.
Jet Streams
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Jet streams are narrow belts of high speed winds that
blow in the upper troposphere and lower stratosphere.
They help meteorologists (track storms) and pilots (save
time & fuel).
Local winds are influenced by the geography of an area.
sea and land breezes and mountain and valley breezes.