Layers of the Atmosphere

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Layers of the Atmosphere

• Troposphere
• Stratosphere
• Mesosphere
• Thermosphere

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Layers of the Atmosphere
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This is an image of the sunrise from space over
the South China Sea. An astronaut would see
something like this clearly defined bands of
color through the atmosphere as the sun rises.
High-peaking cumulus clouds, topping out in
anvil-head cirrus can be seen as black shadows
against the sunlit horizon. The brightness of the
colors in the atmosphere in this photograph is
due to the amount of dust in the atmosphere. More
dust is found in near the equator. There are
various sources for such upper level dust. Many
dust storms in Africa and ash clouds from major
volcanic eruptions are two reasons.
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The Troposphere

• Layer closest to the earth and contains 75 of
  the atmospheres total mass.
• From the Earths surface it extends about 10
  miles high (about 4 from poles and 12 at
  equator).
• Almost all weather takes place in this region.

What is the troposphere?
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• As gases in this region decrease with height the
  air becomes thinner
• As a result, the temperature also decreases with
  height. The air cools gradually as it gets
  further from the earth.
• This is important, because it changes water vapor
  into ice, forming the cold trap.

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• COLD TRAP a temperature region where water
  vapor stops going up. If we had no cold trap,
  water molecules could rise in the atmosphere
  where they would eventually break down into
  oxygen and hydrogen. Leaving earth with limited
  water.

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The Stratosphere

• The stratosphere lies above the troposphere. It
  is about twenty miles deep (extends up to 30
  miles from earths surface).
• Gases are layered and do not mix as much as in
  the troposphere.
• The air is very thin and contains little moisture
  (very little water vapor).

The Earth's Atmosphere
What is the stratosphere?
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• The lower stratosphere is extremely cold, but as
  the temperature rises as altitude increases in
  the stratosphere. This happens because ozone in
  the stratosphere absorbs UV rays from the sun
  which warms the air.
• This layer has the ozone layer in it. It
  protects life of Earth by absorbing harmful UV
  radiation.

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A weather or sounding balloon is a balloon
(specifically a type of high altitude balloon)
which carries instruments aloft to send back
information on atmospheric pressure, temperature,
and humidity by means of a small, expendable
measuring device called a radiosonde. To obtain
wind data, they can be tracked by radar, radio
direction finding, or navigation systems (such as
the satellite based Global Positioning System).
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Relative position of the Earth, Atmosphere, and
the Moon.
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The Mesosphere

• About 20 miles deep - extends to about 50 miles
  from earths surface.
• It is the coldest layer as the temperature drops
  again to as low as -173 degrees F.
• Meteors, small pieces of matter drawn to the
  atmosphere by earth's gravity, become visible to
  the naked eye as they enter the mesosphere and
  are heated through friction caused by collisions
  with air molecules. Gases are thick enough to
  slow down meteorites that enter the atmosphere
  and they burn up leaving behind a fiery trail in
  the night sky.

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The Thermosphere

• The upper atmosphere
• Considered the "hot layer" because it contains
  the warmest temperatures in the atmosphere - 2000
  degrees F or more
• However, because the air is so thin (less dense),
  our bodies would not be able to detect this heat.
  
• There would not be enough molecules bombarding
  your body to transfer heat to your skin.

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• Ionosphere Bottom part of thermosphere. Energy
  from the sun causes gas molecules to become
  electrically charged particles called ions
  cause auroras/northern lights to be seen. AM
  Radio waves bounce off.
• Exosphere Top part of the thermosphere. This is
  the outermost layer. The exosphere is the region
  where molecules from the atmosphere can overcome
  the pull of gravity and escape into outer space.
  Satellites and space shuttle orbit the earth in
  this layer.

Layers of the Earth's Atmosphere