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Albedo of skin?

  1. Jul 9, 2004 #1
    skin can have a very high albedo similar to ice.
    definition albedo: "fraction of solar energy (shortwave radiation) reflected from the Earth back into space..."

    I have hardly any skin pigment. Some areas especially on top of my arms and the complete inside seem to be totally free of pigment. Interestingly I get only sunburnt on areas of skin with at least a tiny bit of pigment, the white areas remain white, which is very good observable when the skin around is burnt. There's a sharp boundary between burnt and white. Try to picture an inversed cheetah here.

    I did an experiment a while ago. Asked friends to put some sunscreen on the rest of my body without touching my arms. Then I exposed the inside of my arms to the sun far too long. These areas did not burn at all and also did not get very warm, the sunburn started from the side of the arms where the amount of pigment increases, except: I have a tiny scar on the inside of my arm. That scar was burnt.

    Now I had an unfortunate accident a while back. Half a litre of boiling water ended up on my forearm. There's no visible scar, no different skin colour visible. Also no difference in how fast my skin burns on the outside of that arm. But interestingly the inside, but only the area where I burnt myself now is affected too by sun, similar to that little scar. Here the skin also gets a little bit brown.

    I guess the albedo theory is indeed a crap theory. It was rather a joke amonst friends. But still I'd like to know why my ('undisturbed') skin is partly not affected at all by shortwave radiation.

    And before someone asks: I usually use sunscreen, the highest I can get (60 in Europe). I made most observations when I was on a field trip in Spain this summer, the sunscreen didn't work and the next pharmacy was about 90 minutes by car away. Try to find those three hours when you're busy all day long :frown:
  2. jcsd
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