UV rays in indirect sunlight?

Hello, folks! With so many smart (and diverse) paddlers here, I thought I’d pose a question. I’m pretty particular about my boats, and try to take care of them when not using them. I keep them under a shed, and they are never hit by direct sunlight. I’m curious- is UV light present in the “ambient”, indirect sunlight, as well as in the bright sunshine? I know that UV light can come through cloud cover and still cause sunburn, but that is still direct sunlight. Any thoughts? Happy paddling, Regan

I’m no expert, but I’d guess
that since UV is just light that is beyond our (but not other creatures’) ability to see, it would be present in indirect as well as direct sunlight. Reflections from water and snow supposedly contain UV light, so that also suggests it’s present in indirect (i.e. reflected and scattered) light. On the other hand, the sky is blue because blue (more energetic) light scatters less than red (less energetic), so I’d guess that the fraction of UV would be lower in indirect than direct sunlight.

I’ll be curious to see what more knowledgeable folk think.


source attenuator detector

Sun atmoshere boat

increase the distance by 25% you cut the amount of light at the detector by 50%.( across all spectrums.)

Throw in another attenuator and the math gets really squirrelly. I would guess the Plaidpaddler could give you the actual formulae, He majored in this stuff, I just audited it.

Depending on the area that the sunlight is bouncing off of would be the big question mark. Some surfaces absord more uv then others.

Now that i have totally confused myself I am going to leave and eat diner…

I would guess that only direct sunlight will have damaging UV rays. I’ve never been sunburn while being in the shade.

UV can be reflected. That’s why you can get sunburned nostrils if you are sking on a sunny day.

Some surfaces are better reflectors than others.

Remember ROYGBIV? Red objects appear red because they reflect the red component of white light more than the other colors. Blue things appear blue because they reflect more blue light than other colors.

UV is Ultra-Violet, so it would fit in as

ROYGBIV UV. Thus light reflecting off of something violet in color probably has more UV content than light reflecting off something red.

UV is present in indirect sunlight - but in much lower amounts than in direct. I think coupled with a suitable protectant (303 or wax, depending on the boat construction) a boat would not be affected too much in the shade.

Flourescent lights also produce some UV light, so artwork or photographs should not be stored directly under them if they are going to be on for long periods of time. Perhaps boats would be affected also. Incandescent lights (bulbs) produce much less.