Characteristics of the Atmosphere

1
Characteristics of the Atmosphere

• Pgs. 4 -9

2
What is the Atmosphere?

• The atmosphere is a mixture of gases that
  surrounds the Earth.
• It contains oxygen for us to breath.
• It protects us from harmful UV rays.

3
Composition of the Atmosphere

• Nitrogen 78
• Oxygen 21
• Carbon Dioxide, Water Vapor, Argon and others
  1
• Dust, volcanic ash, salts dirt and smoke make up
  some of the solids in the atmosphere.
• Water droplets in the air are the most abundant
  liquid in the atmosphere.

4
Atmospheric Pressure and Temperature

• Air pressure is the measure of the force with
  which the air molecules push on a surface.
• Your ears pop on an airplane or elevator when the
  air pressure outside your ears changes and then
  equalize.

5
Pressure

• The Earths atmosphere is held close to the
  surface by Earths gravity.
• Most of the particles in the atmosphere are close
  to the surface and so pressure is greatest
  closest to the surface.
• As you increase altitude, there are less air
  particles applying pressure to you and pressure
  decreases.
• Altitude is the height of an object above the
  Earths surface.

6
Air Temperature

• Air temperature changes as you increase altitude.
• The temperature changes from cooler to warmer
  based upon how solar energy is absorbed as it
  moves through the different layers of the
  atmosphere.
• Some layers will absorb more solar energy than
  others.

7
Troposphere

• The lowest layer of the atmosphere is also the
  densest layer.
• It contains 90 of the atmospheres total mass.
• Most of the Earths carbon dioxide, water vapor,
  clouds, air pollution, weather, and life-forms
  are in the troposphere.

8
Stratosphere

• The stratosphere is the second lowest layer of
  the atmosphere.
• It has very thin air and contains little
  moisture.
• Temperature ranges from -60 0.
• Temperature rises with altitude due to Ozone
  molecules that absorb UV radiation.
• Ozone is made of 3 Oxygen atoms.

9
Mesosphere

• The mesosphere is above the stratosphere and is
  the coldest layer of the atmosphere.
• Temperature decreases with altitude ranging from
  0 (-93) C.
• Large wind storms exist in the mesosphere that
  can exceed 320km/hr winds!

10
Thermosphere

• The uppermost atmospheric layer is the
  thermosphere.
• The temperature increases with altitude.
• Many gases absorb solar radiation.
• Temperatures can reach 1,700 C.
• The particles are very spread out and moving very
  fast, however, it would not feel very warm.
• Heat is not transferred because the particles are
  too spread out.

11
Ionosphere

• Within the lower thermosphere and upper
  mesosphere is an area where x-rays and gamma rays
  are absorbed.
• Here the particles become electrically charged,
  like ions.
• This area is known as the ionosphere.
• Ions can radiate different light colors when
  charged.
• The ionosphere can also reflect AM radio waves.
• The more reflection that occurs, the clearer the
  signal.