1. Basic Properties of the Atmosphere

2. Functions of the Atmosphere
Protection from UV radiation
Allowing light energy to reach the surface and ocean
Regulation of daily temperatures, night & day
Maintains average surface temperature of +15oC instead of -18oC
Transport of energy from the equator to the poles
Transport water vapor which leads to the dynamic processes of the water cycle.
Storage of huge amounts of nitrogen
Reservoir for carbon dioxide and oxygen
Dissipation of natural and man-made emissions
Protection from meteorites

3. Composition Original atmosphere was high in CO2.
High level radiation and photosynthesis changed atmosphere. (H2O)
First 20 km of atmosphere today is a mixture of gases (air)
Amt. of water vapor (<4%).
Sulfur and nitrogen compounds
Solid & liquid particles: dust, pollen, salt, soot, aerosols.
Draw pie chart into your notes

4. Pressure The force exerted by air on an area (weight of air).
Fewer the molecules the lower the pressure
Expressed in millibars (mb) or inches of mercury (Hg)
Measured w/ a barometer.

5. Temperature
Measure of the avg. kinetic energy or speed of molecules in a substance. (air)
Measured w/ a thermometer.
Defines the layers of the atmosphere.
Dew Point temp. measure to which air must cool for condensation to occur.

6. Structure of the Atmosphere
Troposphere
Contains all the weather.
Warmed by surface by conduction and radiation.
Temp. decrease with elevation (-60oC)
Jet stream
80% of atmospheric mass
Tropopause / Isothermal layer
Elevation changes with latitude & season
Max. at equator, min. poles.

7. Stratosphere Stratosphere Clear, dry layer, (limited water vapor)
Temp. inc. w/ altitude
(-60 to 0o C)
Inc. ozone with altitude
Protects surface & life from UV radiation
Ozone absorbs radiation and then releases some as heat.

8. Mesosphere & Thermosphere
Dec. temp. (-100oC)
Meteors begin to burn
Therm:
Inc. temp. (+1000oC)
Layering of atmospheric gases.
nitrogen (green), oxygen (red), helium (yellow), hydrogen.
Auroras
Ionosphere:
Ionized gases
Affected by solar activity
Radio communications