This page contains archived content and is no longer being updated. At the time of publication, it represented the best available science.
NASAs Total Ozone Mapping Spectrometer
(TOMS) provides measurements that enable scientists to accurately
estimate how much of the suns UV-B (290 to 320 nm) radiation reaches the Earth's
surface. Too much exposure to these wavelengths causes sunburn in
The false-color image above is a global map, averaged from TOMS
snapshots collected every day over a one-month period, showing where
more or less UV radiation reaches the surface. Yellow pixels show the
highest levels of radiation at the surface, red and pink hues are
intermediate values, and white indicates little or no UV exposure.
The TOMS sensor flies in a polar orbit, crossing the equator every day
at 12 noon local time, allowing it to measure the total amount of ozone
in a column of atmosphere as well as cloud cover over the entire globe.
Ozone and clouds absorb most of the ultraviolet light passing through
the atmosphere. TOMS also measures the amount of solar radiation
escaping from the top of the atmosphere. It is the combination of those
three measurements that enables scientists to accurately estimate the
amount of UV radiation that reaches the Earth's surface.