Winds

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Winds
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What causes winds?

• A wind is the horizontal movement of air from an
  area of high pressure to an area of low pressure.
• Most differences in air pressure are caused by
  unequal heating of the atmosphere!
• Winds are caused by differences in air pressure.

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Measuring Wind

• Winds are described by their direction and speed.
• Wind direction is determined with a wind vane
  points in the direction the wind is moving!
• Wind speed is measured with an anemometer.
• The increased cooling that a wind can cause is
  called the wind chill factor.

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Local Winds

• Have you ever flown a kite at the beach on a hot
  summer day? Even if there is no wind inland,
  there may be a cool breeze blowing in from the
  water toward the beach. This breeze is an
  example of local winds!
• Local winds are winds that blow over short
  distances.
• They are caused by unequal heating of Earths
  surface within a small area.
• Two types of local winds are sea breezes and land
  breezes.

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Sea Breeze (Morning)
Land heats up faster than water. Hot air over
land rises (Low Pressure), cool air over water
falls (High Pressure). Winds move from the water
(High Pressure) to the land (Low Pressure).
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Land Breeze (Evening)
Land cools off faster than water. Cool air over
land falls (High Pressure), warm air over water
rises (Low Pressure). Winds move from the land
(High Pressure) to the water (Low Pressure).
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Global Winds

• Winds that blow steadily from specific directions
  are global winds.
• Created by unequal heating of Earths surface.
• Warm air rises at the equator and falls at the
  poles.

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Global Winds cont

• The movement of air between the equator and the
  poles produces global winds.
• The way that Earths rotation makes winds curve
  is called the coriolis effect.

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Global Wind Belts

• The five global wind belts are the doldrums, the
  horse latitudes, the trade winds, the prevailing
  westerlies, and the polar easterlies.

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Jet Streams

• Bands of high speed winds
• Hundreds of kilometers wide, but only a few
  kilometers deep.
• Blow from west to east at speeds of 200-400
  km/hr.
• Help airplanes save fuel and time when traveling
  east.

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THE END!

• Work on the worksheet attached to your notes!
• This is your homework!