Glossary : Dobson Unit (DU)
The standard way to express ozone amounts in the
atmosphere. One DU is 2.7 x 1016 ozone molecules per
square centimeter. One Dobson unit refers to a layer of ozone that would
be 0.001 cm thick under conditions of standard temperature (0
oC) and pressure (the average pressure at the surface of the
Earth). For example, 300 Dobson units of ozone brought down to the
surface of the Earth at 0oC would occupy a layer only 0.3 cm
thick in a column. Dobson was a researcher at Oxford University who, in
the 1920s, built the first instrument (now called the Dobson meter) to
measure total ozone from the ground.
Courtesy of NASA
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