Radiation Flashcards
Five fundamental components of the Earth system.
Biosphere, Geosphere, Atmosphere, Cryosphere, Hydrosphere
Major components of the em spectrum.
- stream of photons each traveling in a wave-like pattern carrying energy in the form of heat
- wavelength(m), frequency(hz or s-1), and energy(eV)
What is the order of EM spectrum from smallest wavelength to largest? Highest frequency to lowest? Highest energy to lowest?
Gamma rays, X-rays, UV, Visible, IR, Microwaves, Radio waves
What is the formula for frequency?
f= c (2.9 x 10^-8)/lamda
What is solar flux? What are its units?
Amount of energy per unit area per unit time measured perpendicular to the beam (W/m^2)
What physical law describes the manner in which the intensity of sunlight changes as the observer moves away from the Sun?
Inverse Square Law
- solar flux decreases as the distance from the sun increases
- S = So(ro/r)^2
where So is solar flux at Earth’s surface
ro is the distance between the earth and the sun
r is the distance between the planet and Earth
- So is 1370 W/m^2
- ro is 1AU
What is a blackbody?
Emits or absorbs EM radiation with 100% efficiency at all wavelengths
What are the three physical laws that govern blackbody radiation?
Planck’s Function (radiation emitted by a blackbody is a function of wavelength; thus hotter bodies emit radiation at short wavelengths)
Wien’s Law (objects of different temperatures emit spectra that peak at different wavelengths)
Stefan-Boltzmann Law (flux emitted by a blackbody is proportional to the fourth power of the body’s absolute temperature)
Wien’s Law equation
lamda max = 2898/T
Stefan-Boltzmann Function
E = roT^4
where ro is 5.67 x 10^-8 W/m^2/K^4
What are the main differences between the emission spectra of the Sun and the Earth?
How does reduced or increased solar luminosity could affect the Earth?
How to calculate the effective radiating temperature of planets and of Earth.
Te = (S/4ro(1-A))^(1/4)
Earth: Te = (S/4ro(1-A))^(1/4)
where S = 1370 W/m^2
ro = 5.67 x 10^-8 W/m^-2/K^-4
A = 0.3
