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Wind
Mr. Parr on Wind
Wind
• Horizontally moving air; cause by uneven
heating of the Earth’s surface, which
creates warm and cool air masses,
resulting in differences in air pressure from
place to place; moves from high pressure
area to low pressure area, like when
deflating a balloon
Gust
• A brief sudden increase in wind speed
Local Wind
• Moves across small distances close to
Earth’s surface; unpredictable; changes
frequently with air pressure fluctuaton (ex.
Sea breeze, land breeze, Chinook, Santa
Ana, etc.)
Global Wind
• Moves great distances over the globe;
predictable and stable; also called
atmospheric circulation (ex. Polar
Easterlies, Prevailing Westerlies, Trade
Winds)
Trade Winds
• Winds that occur between 30 N and 30 S,
blow from East to West; Blows
continuously toward the Equator, global
winds
Prevailing Wind
• A wind that usually blows from one
direction (ex. West to east)
Prevailing Westerlies
• Winds that occur between 30 and 60 in
both hemispheres; blow from west to east;
blow towards the poles
Polar Easterlies
• Winds that occur between 60 and 90 in
both hemispheres; blow from east to west;
blow away from poles
Wind Chill
• The “feel like” temperature on a cold day
when you factor in the winds
Jet Stream
• A strong wind found 6-9 miles up in the
troposphere. A jet stream can reach
speeds of ~50-200 mph. Jet streams
steer the movement of air masses and
weather systems. Above North America
the jet stream moves weather from West
to East. It can change locations on global
conditions.
Learn Some More…
• http://www.weatherwizkids.com/weatherwind.htm
Sea Breeze
• A convection current where air flows from
sea to land during the daytime; a local
wind (land heats up and cools down faster
than water)
Land Breeze
• A convection current where air flows from
land to sea during the nighttime; a local
wind (land heats up and cools down faster
than water)
Watch This…
• Check out this animation of land and sea
breeze
• http://www.classzone.com/books/earth_sci
ence/terc/content/visualizations/es1903/es
1903page01.cfm
Sea
•
vs.
During the day, land gets heated by
the Sun much quicker than water. As
the land becomes warmer, it heats the
air in the atmosphere above it. This
causes the air to expand, becoming
less dense, creating a low pressure.
Water heats up less quickly, air above
the ocean also takes longer to
increase in temperature. A higher
pressure is maintained. With a high
pressure above the water and a lower
pressure above the land, conditions
are perfect for a small breeze to
develop. Wind blows from the sea
towards the land along the pressure
gradient in an attempt to equalize
pressure.
Land
• In the night, land cools
down much quicker than
does the waters of the
ocean. As the land
becomes cooler, so does
the air above it. This
results in air becoming
more dense, forming a
high pressure, causing
winds to blow outward
towards the sea.