The unit of measurement used to report the concentration of a gas that is present in the atmosphere or in some part of the atmosphere. It is most often used to measure ozone concentration in the stratosphere (see ozone layer). The unit is the thickness in millimetres of the layer the gas would occupy if all other gases were removed and the gas in question were subjected to sea-level atmospheric pressure. For example, 1-DU of ozone is equal to a layer 0.01 mm thick. The unit is named after Gordon Miller Bourne Dobson (1889–1976), the British physicist who spent many years studying the ozone layer.
Subjects: Ecology and Conservation — Meteorology and Climatology.