1. The Atmosphere
Chapter 22

2. The Atmosphere
Atmosphere: a mixture of gases that surrounds a planet, such as Earth
The atmosphere protects Earth’s surface from the sun’s radiation and helps regulate the temperature of Earth’s surface.

3. Composition of the Atmosphere
Composition of the Atmosphere: is 78% Nitrogen and 21% Oxygen.
Nitrogen is maintained by the Nitrogen Cycle. (with the help of nitrogen-fixing bacteria)
Oxygen is maintained by plants through photosynthesis.

4. The Ozone Ozone: a gas molecule that is made up of three oxygen atoms.
Ozone in the upper atmosphere forms the ozone layer, which absorbs harmful ultraviolet radiation from the sun.
The ozone layer has been damaged by human activities from chlorofluorocarbons (CFCs) released into the atmosphere.

5. Particulates in the Atmosphere
Particulates: tiny solid particles suspended in the atmosphere.
Examples: Volcanic Ash, Dust/Dirt from tornadoes, Salt left from sea spray, Pollen from plants.

6. Atmospheric Pressure
Atmospheric Pressure: the force per unit area that is exerted on a surface by the weight of the atmosphere.
Atmospheric pressure decreases as altitude increases.
Atmospheric pressure is measured using a barometer.

7. Layers of the Atmosphere
Troposphere: the lowest layer of the atmosphere, in which temperature drops at a constant rate as altitude increases; the part of the atmosphere where weather conditions exist.
Stratosphere: the layer of the atmosphere that lies between the troposphere and the mesosphere and in which temperature increases as altitude increases; contains the ozone layer

8. Layers of the Atmosphere
Mesosphere: the coldest layer of the atmosphere, between the stratosphere and the thermosphere, in which temperature decreases as altitude increases
Thermosphere: the uppermost layer of the atmosphere, which temperature increases as altitude increases; includes the ionosphere where interactions between solar radiation causes auroras

9. Layers of the Atmosphere

10. Temperature Inversion
Temperature Inversion: the layering of warm air on top of cool air. Warm air is less dense than cool air and can trap cool polluted air beneath it.

11. Solar Energy and the Atmosphere
All of the energy that Earth receives from the sun travels through space between Earth and the sun as radiation.
Electromagnetic Spectrum: all of the frequencies or wavelengths of electromagnetic radiation.

12. Solar Energy and the Atmosphere
About 70% of the solar energy that reaches Earth is absorbed by Earth’s surfaces and by the atmosphere. The remainder is reflected back into space.
Albedo: the fraction of solar radiation that is reflected off the surface of an object

13. Solar Energy and the Atmosphere
Mirage: occurs when warm air near Earth’s surface bends light rays to produce reflections.

14. The Greenhouse Effect
Greenhouse Effect: the warming of the surface and lower atmosphere of Earth that occurs when carbon dioxide, water vapor, and other gases in the air absorb and reradiate infrared radiation.

15. The Greenhouse Effect
Increases in the amount of carbon dioxide may intensify the greenhouse effect and may cause Earth to become warmer in some areas and cooler in others.

16. The Greenhouse Effect

17. Conduction vs. Convection
Conduction: the transfer of energy as heat through a material
Convection: the movement of matter due to differences in density that are caused by temperature variations; can result in the transfer of energy as heat

18. Atmospheric Circulation
Coriolis Effect: the apparent curving of the path of a moving object from an otherwise straight path due to Earth’s rotation.
Objects deflected to the right in the Northern Hemisphere and are deflected to the left in the Southern Hemisphere.

19. Global Winds
Trade Winds: prevailing winds that blow from east to west from 30 latitude to the equator in both hemispheres
Westerlies: prevailing winds that blow from west to east between 30 and 60 latitude in both hemispheres
Polar Easterlies: prevailing winds that blow from east to west between 60 and 90 latitude in both hemispheres

20. Global Winds

21. Jet Streams
Jet Stream: a narrow band of strong winds that blow in the upper troposphere.

22. Local Winds
Land and Sea Breezes: A cool wind moving from water to land is a sea breeze and a land breeze flows from the cool land toward the warmer water.
Mountain and Valley Breezes: A valley breeze blows upslope and mountain breezes blows down slope.