Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Solar radiation

  1. Jun 2, 2014 #1
    Can anyone speak on the spectrum of sunlight reaching the upper atmosphere and the surface ? Specifically I interested in finding out if there are any IR wavelengths disproportionally represented when compared to the original source.

    Please limit responses to constructive ones.
  2. jcsd
  3. Jun 2, 2014 #2


    User Avatar
    Science Advisor
    Gold Member

    By "upper atmosphere" do you mean above the atmosphere? If you are above the Earth's atmosphere, the spectrum of sunlight reaching you would be almost exactly that as given off by the sun. If you are inside the Earth's atmosphere, then many wavelengths get filtered out by the atmosphere itself, including UV radiation being filtered out by the ozone layer.
  4. Jun 2, 2014 #3


    User Avatar
    Science Advisor
    Gold Member

    Try this: http://en.wikipedia.org/wiki/Air_mass_(solar_energy)

    The charts show solar radiation at the top of the atmosphere, the black body (ideal) spectrum for the sun, and the solar spectrum at the ground. Note the many gaps in the last - these are the wavelengths absorbed by the atmosphere.
    Last edited by a moderator: Jun 2, 2014
  5. Jun 2, 2014 #4
    Thanks ultra, since this shows a nice smooth average decline I get the impression that this exclusively speaks to attenuation/absorption of incoming solar radiation. Im wondering if when we add the radiation reflected/emitted from the ground and the IR emitted from the surrounding excited gas molecules are there any wavelengths within the IR part of the spectrum that show unexpected peaks.

    Making up numbers for an example would there be peaks at 75 micrometers and 150 micrometers that would correspond to the amount emitted by excited gas molecules.

  6. Jun 2, 2014 #5


    User Avatar
    Science Advisor
    Gold Member

    There has been a great deal of research on the solar spectrum at ground level, dating back probably well into the 1800's. Bunsen & Kirchoff began photographing stellar and solar spectra in 1860:

    For an introduction to the measurement issues see:

    With the right concepts you should be able to find whatever interests you via any university library, or Google Scholar.
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook