BIOL 100 Chapter Notes - Chapter 46: Background Radiation, Electromagnetic Radiation, Atmospheric Railway
Textbook Notes
Chapter 46
Climate Systems and the Biosphere
Concept 1: Climate Change
The Sun
Sole source of life on earth
Electromagnetic wave energy transfer (radiation) accounts for nearly all energy transfer from the sun, and is the
primary source of energy for the atmosphere and the entire climate system
Radiant - for energy to reach the world it has to be this
The other means of heat transfer are conduction and convection both of which would not work in outer space
For the Earth to maintain a steady climate the radiant heat from the sun must equal the radiant heat emitted by
the globe
Incoming radiant heat must equal outgoing radiant heat
Radiation
Short-wave form - predominant in the radiation from the sun
This is primarily in the wavelength range from 0.2 to 4.0 microns which encompasses the visible part of
the spectrum
Provides a source of energy for the climate system as it is absorbed in the atmosphere, clouds, ocean,
land surface, and by living matter
Long-wave form - terrestrial or long-wave type predominant with the radiation emitted by matter in the climate
system
Range for this form is from 4 to 60 microns which is entirely in the invisible infrared part of the
spectrum
Solar Radiation
Coming into the Earth’s atmosphere from above leads to heating as it is absorbed by gases, aerosols and clouds
in the atmosphere, and by the ocean, land, ice and biosphere elements at the Earth’s surface
The absorption is proportional to the intensity of the solar radiation and depends on the properties of
these substances
As the solar radiation is absorbed, there is less radiation available to be absorbed at lower levels
The intensity depends on the temperature of the sun and the distance from the sun to the Earth
The Albedo
Indicative of (inversely related to) the absorption of radiation by that surface
A surface with a high albedo is heated much less than one with a low albedo
At the Earth’s surface, the albedo ranges from about five percent for ocean surfaces and the top surface of dark
thick coniferous forests to 90% for fresh snow
Since much of the reflected and back scattered solar radiation travels back out to space, it is never converted to
heat in the climate system
Document Summary
Electromagnetic wave energy transfer (radiation) accounts for nearly all energy transfer from the sun, and is the primary source of energy for the atmosphere and the entire climate system. Radiant - for energy to reach the world it has to be this. The other means of heat transfer are conduction and convection both of which would not work in outer space. For the earth to maintain a steady climate the radiant heat from the sun must equal the radiant heat emitted by the globe. Incoming radiant heat must equal outgoing radiant heat. Short-wave form - predominant in the radiation from the sun. This is primarily in the wavelength range from 0. 2 to 4. 0 microns which encompasses the visible part of the spectrum. Provides a source of energy for the climate system as it is absorbed in the atmosphere, clouds, ocean, land surface, and by living matter.
