Energy in the Atmosphere Notes
Almost all the Energy in our Atmosphere comes from the Sun
It travels to Earth at electromagnetic waves
§ Most of the energy from the sun travels to Earth as visible light or infrared radiation.
A small amount arrives as ultraviolet radiation:
§ Visible Light
· All the colors of the rainbow.
· The different colors are due to different wavelengths
· Blues are the shortest, Reds are the longest
§ Infrared radiation
· Has long wave lengths
· Not visible
· Felt as heat
§ Ultraviolet radiation
· Has short wave lengths
· Not visible
· Causes sunburns, cancer and eye damage
Sunlight is absorbed or reflected by the atmosphere before it reaches the surface, the rest passes through the atmosphere
Some energy is absorbed:
Ø The ozone layer absorbs most ultraviolet radiation
Ø water vapor and carbon dioxide in our atmosphere absorb some infrared radiation
Ø clouds, dust and other gases also absorb energy
Other energy is reflected
Ø Dust particles in the clouds reflect sunlight back to earth
Ø Scattering: the reflecting of energy, radiation in all directions
o Energy of shorter wavelengths are scattered the most (blue light) (during daytime)
o During sunrise and sunset the atmosphere is very thick and most of the “blue” wavelengths are removed, so we see red
When the Earth’s surface is heated it radiates (sends) most of the energy back into the atmosphere as infrared radiation.
Ø It doesn’t travel all the way to space
Ø It is absorbed by water vapor, carbon dioxide, methane and other gases in the air.
Ø This absorbed energy heats our atmosphere
Ø These gases form a blanket called the “greenhouse effect”