Title: A1256655846KBrqm
1The Structure of the Atmosphere
2I well remember a brilliant red balloon which
kept me completely happy for a whole afternoon,
until, while I was playing, a clumsy movement
allowed it to escape. Spellbound, I gazed after
it as it drifted silently away, gently swaying,
growing smaller and smaller until it was only a
red point in a blue sky. At that moment I
realized, for the first time, the vastness above
us a huge space without visible limits. It was
an apparent void, full of secrets, exerting an
inexplicable power over all the earths
inhabitants.
3- The Function of the Atmosphere
- A. Earths atmosphere allows for life to exist
by - Regulating temperature
- Providing protection from harmful solar radiation
- Providing space for water and nutrient cycles
- The Composition of the Atmosphere
- 78 Nitrogen Gas
- 21 Oxygen Gas (O2)
- 1 other--
- water vapor, carbon dioxide,
- argon, helium, hydrogen,
- ozone, particles (dust, soot),
chlorofluorocarbons, etc.
CO2 and H2O vapor play a critical role in
regulating the amount of heat energy the
atmosphere absorbs.
4- The Structure of the Atmosphere
- A. In order from the top down
- Exosphere
- Thermosphere
- Mesosphere
- Stratosphere
- Troposphere
- The Sky Makes Thunder Emphatically!
Figure 11.2
5- Characteristics of the Troposphere
- Contains most of the atmospheric mass.
- Weather occurs in this layer.
- Pollution and smog collect in this layer.
- Temperature decreases as altitude increases.
- The amount of heat absorbing molecules (CO2, H2O)
decrease as the distance from Earths surface
increases. - The layer closest to the Earths surface.
- Bottom boundary 0 km (sea level)
- Top boundary 10 km, varying from equator to
poles - Approximate Thickness 10 km
6- C. Characteristics of the Stratosphere
- Contains ozone gas (O3) , making the Ozone
Layer. - Jet planes fly here because of steady weather
conditions. - Temperature increases as altitude increases.
- Ozone gas absorbs ultraviolet radiation from the
sun. - Bottom boundary 10 km
- Top boundary 50 km
- Approximate Thickness
- 40 km
7- C. Characteristics of the Mesosphere
- Air molecules are less concentrated in this
layer. - Temperature decreases as altitude increases.
- With the absence of ozone, temperature again
decreases as the number of heat absorbing
molecules decrease. - Bottom boundary 50 km
- Top boundary 100 km
- Approximate Thickness
- 50 km
8- Characteristics of the Thermosphere
- Gas molecules are sparse and widely spaced.
- Temperature increases as altitude increases.
- Molecules are heated faster because they are
closer to the sun and absorb intense solar
radiation. - Temperatures are high (up to 1000 C!), but heat
is low. - Bottom boundary 100 km
- Top boundary 500 km
- Approximate Thickness 400 km
9- Characteristics of the Ionosphere (part of the
thermosphere) - This layer is made of electrically charged
particles called ions. - At the poles, ions interact with air molecules to
form auroras. - Radio waves from earth reflect off the ionosphere
back to Earth. - Ranges from 65 km -500 km above sea level.
10- Characteristics of the Exosphere
- Air molecules are very sparse in this layer.
- Only light gases (Helium Hydrogen) are found
here. - Temperature increases as altitude increases.
- Temperatures are high, but heat is low.
- Bottom boundary 500 km
- Top boundary ???
- There is no clear distinction between the top
boundary and outer space.
11Summary Diagram