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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.
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) ?Chronos said: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.
Solar UV is measured using a device called a spectroradiometer, which measures UV radiation at different wavelengths. The data collected by the spectroradiometer is then used to calculate the solar UV index.
The solar UV index is a numerical scale that represents the intensity of UV radiation from the sun at the Earth's surface. It ranges from 0 to 11+ and is used to indicate the potential for harm from UV exposure.
The measurement of solar UV on earth can be affected by various factors such as cloud cover, ozone depletion, altitude, and atmospheric pollution. These factors can either enhance or reduce the amount of UV radiation reaching the Earth's surface.
The solar UV index is used to inform the public about the potential risk of UV exposure and to encourage people to take necessary precautions to protect themselves from UV radiation. It is also used by scientists to monitor changes in UV radiation levels over time.
Yes, it is possible to measure solar UV levels in real-time using ground-based or satellite-based instruments. This allows for more accurate and timely information on UV levels, which can help individuals make informed decisions about sun protection.