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Ch. 15. Atmosphere . The atmosphere is a mixture of gases. Nitrogen and oxygen make up most of the Earth’s atmosphere. Air Pressure decreases as altitude increases. The composition of atmospheric layers affects their temperature. .
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Ch. 15 Atmosphere
The atmosphere is a mixture of gases. • Nitrogen and oxygen make up most of the Earth’s atmosphere. • Air Pressure decreases as altitude increases. • The composition of atmospheric layers affects their temperature.
Throughout the atmosphere, there are changes in air pressure, temperature, and gases. • Air pressure decreases as altitude increases.
Temperature differences in the atmosphere are a result of the way solar energy is absorbed as it moves downward through the atmosphere.
Layers of the Atmosphere • Troposphere- lowest atmospheric layer. • It is the layer in which we live • Densest layer • All weather occurs here
Layers of the Atmosphere • Stratosphere- contains the ozone layer which protects us from harmful UV radiation
Layers of the Atmosphere • Mesosphere- coldest atmospheric layer
Layers of the Atmosphere • Thermosphere- uppermost layer of the atmosphere
Atmospheric Heating • Energy from the sun is transferred through the atmosphere by radiation, thermal conduction, and convection. • Radiation is energy transfer by electromagnetic waves. • Thermal conduction is energy transfer by direct contact. • Convection is energy transfer by circulation.
The green house effect is Earth’s natural heating process. • Increasing levels of green house gases could cause global warming.
Energy that reaches the Earth’s surface is absorbed or reflected. • Energy is transferred through the atmosphere by conduction and convection.
Global Winds and Local Winds • Winds blow from areas of high pressure to areas of low pressure. • Pressure belts are found approximately ever 30 degrees of latitude. • The Coriolis effect causes wind to appear to curve as it moves across the Earth’s surface.
Global winds include the polar easterlies, the westerlies, and the trade winds.
Local winds include sea and land breezes and mountain and valley breezes. • Local winds move short distances, can blow in any direction, and are influenced by geography.
Air Pollution • Primary pollutants are pollutants that are put directly into the air by human or natural activity. • Secondary pollutants are pollutant that form when primary pollutants react with other primary pollutants or with naturally occurring substances.
Transportation, industry, and natural resources are the main sources of air pollution. • Air pollution can be reduced by: • legislation, such as the Clean Air Act • Technology, such as scrubbers • Changes in lifestyle
Air pollution can heighten problems associated with allergies, lung problems, and heart problems. • The Clean Air Act has reduced air pollution by controlling the amount of pollutants that can be released from cards and factories.