A new instrument mounted on an aircraft has been used by the EPA to measure ozone concentration and distribution in a column of atmosphere for the first time. The instrument is called Ultra Violet Differential Absorption LIDAR (UV-DIAL). Previous instruments could give such data on ozone only in the area immediately surrounding the aircraft. LIDAR, light intensification detection and ranging, is similar to radar but uses electromagnetic waves of much shorter wavelength.
The new instrument uses light of two different wavelengths. One of the wavelengths is absorbed by ozone, and the other is not. The difference between the two combined signals is analyzed by the UV-DIAL to determine concentration and distribution of ozone in a column beneath the aircraft.