Monday, February 22, 2010

Fresh snow is the most reflective natural surface on earth

Fresh snow is the most reflective natural surface on earth because it has the highest albedo, or how strongly an object reflects light from other light sources (i.e. the Sun). At first thought you might think that water would be the most reflective surface on earth - on sunny days a body of water (with an albedo of can look like a mirror of the sea, and snow just remains white - but water allows some of the light absorb below the surface, while snow reflects almost all light back to the sky.

Sample Albedos

Surface Typical Albedo
Fresh asphalt 0.04
Worn asphalt 0.12
Bare soil 0.17
Green grass 0.25
Desert sand 0.40
New concrete 0.55
Ocean Ice 0.5–0.7
Fresh snow 0.80–0.90

Still don't get it? Check out this diagram...

The albedo of snow drops significantly as the snow gets older. As snow its on the ground it gets dirtier and the surface becomes rough, leaving room for the light of the sun to be absorbed. This is why ski goggles are so important - without them the snow would be blinding. Last weekend I visited Shawnee Mountain in PA to give skiing another chance, and I'm thankful that my Aunt had some ski goggles to lend me, because there was a lot of fresh snow (the only thing brighter than the snow was Jeremy's lime green jacket and matching snowboard).

I had a pretty good time and enjoyed a couple of good runs (conquering the Little Chief trail in one try and created a new method for skiing called "Fauxhawk and Blowout") until my knee started to hurt.

Little Chief

Then I retired to the lounge, enjoyed a Bud Light (or two) and listened to live music courtesy of Steve McDaniel (of the Steve McDaniel Band). Steve did an awesome cover of Johnny Cash's A Boy Named Sue, and was nice enough to give me a CD. Check him out on MySpace Music.

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