Understanding Solar UV Radiation and Its Impact on Earth: A Brief Overview

[neilparker62]

Is solar uv completely blocked from reaching Earth or do we just need more sensitive uv detectors to make ground-based observations? In particular of the uv wavelengths corresponding to hydrogen Lyman series lines.

 

[Chronos]

Sunburns offer compelling evidence that some fraction of solar UV does reach the ground. The atmosphere screens out most, but not all UV radiation. I suspect some radiation at these wavelengths is visible in the Lyman series, but, most is in the Balmer series.

 

[neilparker62]

Sunburns offer compelling evidence that some fraction of solar UV does reach the ground. The atmosphere screens out most, but not all UV radiation. I suspect some radiation at these wavelengths is visible in the Lyman series, but, most is in the Balmer series.

Thanks - the reason I asked because we've got a whole lot of fancy hardware up in space examining distant stars and galaxies yet the data on our very own special star, the sun is pretty woeful as far as I can make out. I have researched sources of solar Lyman Alpha and Lyman Beta profiles and so far the best I can find is Artzner's 1978 profile and Lyman Beta extracted via 'densitometry' from Tousey's early rocket based observations. I would like to see Artzner's very careful profile at higher resolution. I would like to see what's going on in the small dips you see in left and right peaks. I would like to have a precision measurement of a key reference wavelength namely the geo-coronal absorption rather than seeing attempts to whitewash it out of the picture possibly compromising the profiles. I would also like to see precision measurements on the separation of the peaks in these profiles. Does that vary? Should it vary ? Do we need to be very careful where we measure (ie at disk centre of "quiet sun" rather than in wavy limb filaments or whatever) ?

 

[SteamKing]

If you're not too clear on how UV radiation affects the Earth and things living on the surface, you should peruse these fact sheets from the US EPA:

http://www.epa.gov/sunwise/doc/uvradiation.html

After all, sun tans do not come solely out of a bottle.