Wind
Wind
• Wind: the horizontal movement of air
• Wind is caused by the uneven heating of Earth’s
surface
Wind
• Wind speed is measured using an anemometer
• Wind direction is measured using a weathervane
The Coriolis Effect
• The Coriolis effect: a shift in the path of a
moving object caused by the rotation of the
earth on its axis
• Animation
• https://www.youtube.com/watch?v=i2mec3v
geaI
• Video
• hank Coriolis effect
• airplane
Coriolis Effect
• As wind blows, earth rotates underneath it, making
the wind appear to curve
• Northern Hemisphere: wind is deflected to the right
• Southern Hemisphere: wind is deflected to the left
Local Winds
• Land and Sea Breezes: Land
heats up and cools down faster
than water
• Daytime: low pressure air rises
, wind comes from the sea and
is called a sea breeze
• Nighttime: high pressure air
sinks, wind blows out to sea
and is called a land breeze
Local Winds
• Mountain and Valley Breezes
• Daytime: warm air from the valley
moves up and is called a valley
breeze
• Nighttime: mountains cool down
more quickly than valleys
• Cool air sinks down the mountain
and is called a mountain breeze
Global Winds
global winds
• Each hemisphere has three looping patterns
called convection cells (Hadley cells)
• Each cell corresponds to a wind belt,
characterized by winds that blow in one main
direction (prevailing winds)
• Winds are named according to the direction
they came from (winds blowing west to east
are called “westerly”)
Global Winds
• Winds are named for the direction they come from
• Hadley Convection Cells: Vertical convection
currents in the atmosphere (Brown)
• global winds
Global Winds
• Trade winds: between the equator and 30⁰ North
or South latitude (green)
• Westerlies: between 30⁰ and 60⁰ N or S latitude
(red)
• (Polar) Easterlies: between 60⁰ and 90⁰ N or S
latitude (blue)
Global Winds
• Doldrums: areas along the equator where there is
little wind (orange)
• Horse Latitudes: areas near 30⁰ N or S latitude
where there is little wind (Yellow)
Global winds
• Jet Stream: narrow bands of high speed winds in
the stratosphere (purple)
• Jet streams can affect airline routes and the paths
of storms
Weather
• Weather: the current conditions of the atmosphere
• All weather takes place in the troposphere
• Included in a weather report: Air temperature, air
pressure, cloud type, wind speed and direction, the
amount and type of precipitation, moon phase
Weather
• Weather changes every day because the air in the
atmosphere is always moving
• Weather also changes because the energy from the
sun is constantly being redistributed after it
reaches earth’s surface
Weather
• Meteorology: the study of atmospheric changes
(weather)
• Climate: the long term weather patterns of a
certain area
• Climatology: the study of the climate and climate
change
• Weather can change rapidly, climate changes
slowly over time