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UV index
UV index or clear-sky ultraviolet index is the effective UV irradiance reaching the Earth's surface (1 unit equals 25 mW/m2).
The clear-sky UV index is based on the CIE action spectrum for the susceptibility of the caucasian skin to sunburn (erythema) and it is valid for cloud-free conditions at local solar noon.
UV radiation
The ultraviolet region of radiation covers the wavelength range 100-400 nm and is divided into three bands: UVA (315-400 nm), UVB (280-315 nm) and UVC (100-280 nm).
As sunlight passes through the atmosphere, all UVC and approximately 90% of UVB radiation is absorbed by ozone, water vapour, oxygen and carbon dioxide. UVA radiation is less affected by the atmosphere. Therefore, the UV radiation reaching the Earth’s surface is largely composed of UVA with a small UVB component.
UV index maps
(External links to UVindex maps open in a new browser window.)
Europe and world UV index maps
Space weather and solar activity
Current web page, "UV index of the Sun today" is a part of Space weather and solar activity section of Lunaf.com. You may want to visit previous or next page too:
