UV index 4 from 29 March

GREVILLE

Re: UV index 3 from ~14 March

Post by GREVILLE »

So figures on a UV index can be boosted by conditions encouraging more reflected light. This must account for a comment heard by a BBC weather forecaster who said that sunlight can be even stronger with patchy fairweather cloud than gin-clear blue skies.
stephenprudence

Re: UV index 3 from ~14 March

Post by stephenprudence »

GREVILLE wrote:So figures on a UV index can be boosted by conditions encouraging more reflected light. This must account for a comment heard by a BBC weather forecaster who said that sunlight can be even stronger with patchy fairweather cloud than gin-clear blue skies.
Where have you come across blue gin?? :lol:

Bombay Sapphire?

Yes certainly high cloud can magnify UV.. however it won't be taken on board by UV models.
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Yorkshire Kris
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Re: UV index 3 from ~14 March

Post by Yorkshire Kris »

All this talk of UV and no mention of skin cancer? Remember to keep convered up and apply sunscreen. It doesn't need to be hot and sunny for uv levels to be damaging to the skin.
otorongo
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Re: UV index 3 from ~14 March

Post by otorongo »

Yorkshire Kris wrote:All this talk of UV and no mention of skin cancer? Remember to keep convered up and apply sunscreen. It doesn't need to be hot and sunny for uv levels to be damaging to the skin.
Yeah skin cancer in index 3... never leave the house without a tank...

Image

I don't use protection for indices 11 or below, it's not really necessary, and strong sun is needed for good health. Using sun protection defeats the point of being in the sun as it cuts off your skin from the beneficial UV light.
Nathan

Re: UV index 3 from ~14 March

Post by Nathan »

otorongo wrote:
Nathan wrote:And haze from pollution can actually increase UV levels too...
Increase or decrease?

Coastal areas also have higher UV levels due to the light reflected by the water.

When you're out skiing in the Alps in the winter you can get sunburns, not only because of the altitude but also the sn*w reflecting more UV (and the sun is 5 deg higher down there).
Increase. This is taken from the WHO website:
UV intensities are highest under cloudless skies. Clouds generally reduce UV intensity, but light or thin clouds
have little effect and under certain conditions may even enhance the UV intensity. Hazy days generally have
higher amounts of water vapour; UV scatter in the atmosphere increases and can result in a higher personal UV
exposure. Thus, even though haze or cloud cover can cause one to feel cooler, the UV exposure can still be high.
http://www.who.int/uv/publications/proUVrad.pdf
Nathan

Re: UV index 3 from ~14 March

Post by Nathan »

otorongo wrote:
Yorkshire Kris wrote:All this talk of UV and no mention of skin cancer? Remember to keep convered up and apply sunscreen. It doesn't need to be hot and sunny for uv levels to be damaging to the skin.
Yeah skin cancer in index 3... never leave the house without a tank...

[ Image ]

I don't use protection for indices 11 or below, it's not really necessary, and strong sun is needed for good health. Using sun protection defeats the point of being in the sun as it cuts off your skin from the beneficial UV light.
With respect the amount of UV one can take is dependent on the colour of your skin, most of us would be very badly burnt at much much lower levels than you indicate. A UV of between 3 to 6 is 'moderate' for light skinned people & fair skinned people can burn at lower levels than that. Even people with naturally brown or black skin have a medium to high risk of burning in UV levels of 7 to 10, let alone 11! :?

Slip, slap, slop people icon_thumright
otorongo
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Re: UV index 3 from ~14 March

Post by otorongo »

Nathan wrote:
UV intensities are highest under cloudless skies. Clouds generally reduce UV intensity, but light or thin clouds
have little effect and under certain conditions may even enhance the UV intensity. Hazy days generally have
higher amounts of water vapour; UV scatter in the atmosphere increases and can result in a higher personal UV
exposure. Thus, even though haze or cloud cover can cause one to feel cooler, the UV exposure can still be high.
I think what this quote means to say is that in hazy conditions the UV is more diffused, so when you're in the shade you get more UV from the diffused light than you would on a clear day.

With clear skies the light is less diffused and more direct. As a result you get little UV in the shade, but full-on UV in the sun, assuming you're exposed to it properly - sitting at the optimal angle etc.

So as long as you are in the sun, clear is better than hazy. And you know where I will be... and how close to optimal my exposure will be :D

It is only those pale, photophobic people who spend all day indoors and squint at the sun when they come out of their boxes that will get more UV in hazy conditions, because they always seek shade and the haze will pump extra UV into the shade (at the cost of the sun-hungry people like myself).
stephenprudence

Re: UV index 3 from ~14 March

Post by stephenprudence »

Ive never burnt below UV 7, but I have burnt pretty spectacularly in UV 10 .. when I was in Mediterranean. I'm part of Britain darker quartile too (as a native), but Ive known people to say they've been burnt in February before.
otorongo
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Re: UV index 3 from ~14 March

Post by otorongo »

I've been burnt in January (in Costa Rica and Mexico), November and December (in Rio) but never in February, as by February my skin is already dark enough.

Recent studies suggest the lack of sun causes more cancer (not just skin, but all kinds) than the excess of it. For example in Britain the further South you go the lower the percentage of cancer cases.

I find that the sun in London is already too hot for comfort, but a breeze can go a long way icon_sunny
Exotic Life

Re: UV index 3 from ~14 March

Post by Exotic Life »

UV 3 possible here by the end of this week.
otorongo
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Re: UV index 3 from ~14 March

Post by otorongo »

Exotic Life wrote:UV 3 possible here by the end of this week.
Same here :)

Weekend and the following week looking sunny icon_sunny with index 3 every day excepting Monday.
stephenprudence

Re: UV index 3 from 8 March

Post by stephenprudence »

UV 1 here is also were due this week.
GREVILLE

Re: UV index 3 from 8 March

Post by GREVILLE »

Probably enjoyed UV 2 to 3 today. Wonderful to do some gardening in a tee shirt. My face has a little glow as I post this.
Nathan

Re: UV index 3 from 8 March

Post by Nathan »

A UV of 5 is forecast here next week icon_sunny
otorongo
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Re: UV index 3 from 8 March

Post by otorongo »

Nathan wrote:A UV of 5 is forecast here next week icon_sunny
Good for you, that's already close to sufficient icon_sunny
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