as a self-propogating elecctric and magnetic wave that is similar to a wave that moves on the surface of a pond
the wave consists of a series of crests and troughs. the distance between two adjacent crests
greek letter a (lambda). an observer standing at a fixed point in the path of the wave would be passed by a given number of crests in one second. this number is called the frequency of the wave
v (nu) greek letter
a single particle or pulse, of electromagnetic radiation is referred to as a photon.
the full range of forms of electromagnetic radiation, which differ by their wavelengths (or by their frequencies), makes up the e.p.
or visible light, consists of a relatively narrow range of wavelengths, from about 400nm to 700nm.
the coloros of the rainbow--in other words, the range of component wavelengths of visible light--are referred to as the visible spectrum
are significantly longer than those of visible light. hence, it is convenient to keep track of them in units called micrometers (um) rather than in nanometers.
ultraviolet (UV) radiation
about 10% of the Sun's energy is emitted at wavelengths shorter than those of visislbe light
wavelengths of the ultraviolet region extend from 400nm down to about 10nm
is the amount of energy (or number of photons) in an eletromagnetic wave that passes perpendicularly through a unit surface area per unit time
is expressed mathematically as
S= S 0 (r0 / r ) ^2
kelvin (absolute) temperature scale
measured in units called kelvins (K)
Scientists, particularly those studying climate, often use this system
black body radiation
the radiation emitted by a blackbody
states that the flux of radiation emittted by a blackbody reaches its peak value at a wavelength amax that depends inversely on the body's aboslute temperature
according to this rule, hotter bodies emit radiation at shorter wavelengths than do colder bodies
amax (=approx) is the wavelength of maximum radiation flux in micrometers
the sun emits most of its energy, including visible radiation, from the surface layer, and photosphere
stefan boltzmann law
states that the energy flux emitted by a blackbody is related to the fourth power of the body's absolute temperature
effective radiating temperature
we do this by defining a quantity Te that represents the ert of the planet. this temperature is the temperature that a true blackbody would need to have to radiate the same amount of energy that Earth radiates
the decrease with altitude follows the barometric law, which states that atmospheric pressure decreases by about a factor of 10 for every 16km increase in altitude
which extends from the surface up to 10 to 15km (higher in the tropics, lower near the poles)
immediately above the troposphere is the stratosphere, which is located from about 10 to 15km to 50 km above the surface and in which temperature increases with altitude
above the stratosphere, temperature decreases with altitude in the mesosphere (from about 50km to 90km) and then increases once again in the uppermost layer, the thermosphere (above about 90km)
is a process in which heat energy is transported by the motions of fluid (a liquid or a gas).
is the heat energy released or absorbed during the transition from one phase--gaseous, liquid or solid--to another
is the transfer of heat energy in the form of electromagnetic waves
is the transfer of heat energy by direct contact between individual molecules
H2O rotation band
The frequency (or wavelength) of the radiation that can be absorbed or emittted depends on the molecules structure