Sun bath points to ponder - The Traveller


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Friday, April 8, 2011

Sun bath points to ponder


In the month of July in the northern hemisphere, the risk of sunburn due to UVB is 100 times greater than in winter.


The intensity of the sun is highest at the equator where the radiation is vertical and thus has a shorter path through the ozone layer.

The altitude

The amount of UVB increases by 4% every time you go up to 300 meters. This partly explains the greater risk of sunburn in the mountains. But why the sun is it more aggressive in the mountains? Is it because that altitude, it approaches the sun? Not at all, relative to the distance from earth to sun (150 million kilometers), an increase of a few hundred meters is not significant. By cons, as the distance from the sea level, the atmosphere traversed by the UV is scarce. Its action "filter" is thus reduced.

The schedule

Morning and evening the radiation is more oblique through the ozone layer between 11 hours and 14 hours when the UVB radiation is maximal.


Depending on their thickness and their height, they can filter some UV, but a sunburn is still possible under a cloudy sky.

The soil

The power of reflection is different depending on whether the snow (85%), sand (17%), water (5%) or grass (3%). Thus, the mountain combines all the dangers of UVB with more and more reflection on the snow.

You'll set sail for a holiday? Know that the foam in the wake of a boat doubles the amount of UV radiation received, the sails or deck painted the raise even more.

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