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Data Product: ERYTHEMAL UV
EXPOSURE
This is an example of TOMS global image of
daily erythemal UV exposure. Ultraviolet radiation is at shorter
wavelengths than the visible spectrum (400 to 700 nm) and is divided into
three components: UV-A (315 to 400 nm), UV-B (280 to 315 nm) and
UV-C (less than 280 nm). The shorter wavelengths that comprise UV-B
are the most dangerous portion of UV radiation that can reach ground
level. Atmospheric ozone shields life at the surface from most of the
UV-B and almost all of the UV-C. UV-A and UV-B are reduced by a small
amount from Rayleigh scattering in the atmosphere. All forms of UV
radiation are reduced by cloud cover. Persistent lack of cloud cover in
some regions (e.g. Australia and South Africa) increases the danger from
UV radiation compared to similar latitudes in the Northern Hemisphere.
Chemical processes in the atmosphere can affect the amount of ozone, and
therefore, the level of protection provided by the ozone in the
statosphere and troposphere. This thinning of the atmospheric
ozone leads to elevated levels of UV-B at the earth's surface
and increases the risks of DNA damage
and other cellular damage in living organisms.
We organize our data and image products by the dates a specific
spacecraft returned data. Select from the buttons below to get
images and data for the dates of interest.
NEW!  Single-wavelength UV
irradiances for 305, 310, 320, and 380 nm. and erythemal local-noon
irradiances are now available for inspection in
a 1.0 X 1.0 gridded ASCII format. Final validation is in
progress.
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