A unit of measurement for the total amount of ozone in the atmosphere above a point on the earth's surface, one Dobson unit being equivalent to a layer of pure ozone 0.01 mm thick at standard temperature and pressure.
- ‘The ozone hole area is defined as the size of the region with total ozone below 220 Dobson units.’
- ‘The unit of measure is a Dobson unit, which is equivalent to 1 milli-centimetre atmosphere of column ozone.’
- ‘Ground-based measurements of ozone for all 3 days were within 8 Dobson units.’
- ‘Ozone measurements from the first week of March already show a region over the North Atlantic with very low ozone levels (<250 Dobson units).’
- ‘This ratio changed by less than 1% as column ozone varied by 50 Dobson units, about 300 DU, so for subsequent calculations we used only the ratios computed for the central ozone value.’
1980s from the name of G. M. B. Dobson (1889–1976), British meteorologist.