1. Solar Energy and the Atmosphere
Earth and Space Science
Ms. Pollock

2. Radiation All forms of energy that travel through space as waves
Speed 300,000 km/s
Wavelength – distance from crest to crest or trough to trough
Electromagnetic spectrum – complete range of wavelengths of electromagnetic waves

3. Electromagnetic Spectrum

4. The Atmosphere and Solar Radiation
Upper atmosphere absorbs almost all radiation with wavelength shorter than visible light
Molecules of N and O absorb X rays, gamma rays, UV rays
In stratosphere, oxygen uses radiation to form ozone

5. The Atmosphere and Solar Radiation

6. The Atmosphere and Solar Radiation
Most solar rays reaching lower atmosphere longer wavelengths
Infrared radiation absorbed by CO2

7. Scattering
Particles and gas molecules in atmosphere reflect and bend solar rays
Some radiation back to space
Sunlight from all directions
Blue sky and red sunrise and sunset

8. Reflection Earth’s surface absorbing or reflecting energy
Physical properties of surface determine absorption or reflection
albedo – fraction of solar radiation reflected by a surface

9. Absorption and Infrared Energy
Not all radiation ever absorbed
Heating of surface materials
Reemission of radiation with altered wavelength
Necessary for maintenance of temperature of lower atmosphere
Causes mirage

10. Absorption and Infrared Energy

11. The Greenhouse Effect
Greenhouse glass allows light and infrared rays in.
The glass also prevents the reflected rays from escaping the greenhouse.
Earth’s atmosphere acts in the same way.

12. Human Impact on the Greenhouse Effect
Generally, the amount of energy entering the atmosphere and the amount of energy leaving the atmosphere is equal.
Human activities upset the balance
Burning fossil fuels

13. Variations in Temperature
Unequal heating of Earth
Delay between radiation reaching Earth and temperature increasing
Warmest time of day mid- to late afternoon
Depends on latitude, surface features, season, and time of day

14. Latitude and Season
Because of Earth’s shape, sun does not strike everywhere at same angle
At equator, rays striking at near 90º
More intense radiation
Seasonal temperature variation because of Earth’s tilt on axis
Opposite seasons in northern and southern hemisphere

15. Latitude and Season

16. Water in the Air and on the Surface
Water vapor stores heat.
Wide temperature variation in very dry areas or areas with high altitudes
Land areas near large bodies of water less variant, due to specific heat of water
Temperature variations caused by wind patterns

17. Water in the Air and on the Surface

18. Conduction
Transfer of energy from one substance to another by direct contact
Results from particle collisions
Air a poor conductor due to large spaces between particles
Conduction only in lower portion of atmosphere

19. Conduction

20. Convection
Process by which a fluid rises or sinks because of a difference in temperature
Result of uneven heating
Primary source of heating in lower atmosphere
Pressure difference between air of different temperatures creates wind.

21. Convection