1. 17.1 Atmosphere Characteristics  D) Variable Components Water vapor 1) Water vapor is the source of all clouds and precipitation. water vapor absorbs heat given off by Earth. It also absorbs some solar energy.

2. 17.1 Atmosphere Characteristics 2) Ozone is a form of oxygen that combines 3 oxygen atoms into each molecule (O 3 ). a) Without O 3 absorbing UV radiation, our planet would be uninhabitable for many living organisms.

3. 17.1 Atmosphere Characteristics  3) Human Influence a) Emissions from vehicles account for nearly half the primary pollutants by weight.

4. Primary Pollutants

5. 17.1 Atmosphere Characteristics 1) The atmosphere rapidly thins as you travel away from Earth. 2) Atmospheric pressure = weight of the air above.  E) Pressure Changes

6. Atmospheric Pressure vs. Altitude

7. 17.1 Atmosphere Characteristics 4 layers. 1- troposphere 1- troposphere is the bottom layer -temperature decreases with an increase in altitude. 2- stratosphere temperature remains constant to a height of about 20 kilometers. It then begins a gradual increase until the stratopause.

8. Snowy Mountaintops Contrast with Warmer Snow-Free Lowlands

9. 17.1 Atmosphere Characteristics 3-mesosphere- 3-mesosphere- immediately above the stratosphere = decreasing temperatures with height. 4- thermosphere 4- thermosphere above the mesosphere = increasing temps, absorption of very short-wave solar energy by oxygen.

10. Thermal Structure of the Atmosphere