Study of Laser Radar System Using the Differential Absorption Method for Detection of Air Pollutants

Abstract

A laser radar system using the differential absorption method for remote measurement of atmospheric NO₂ and SO₂ is studied. A simultaneous two-wavelength dye laser for transmitter and a simultaneous two-wavelength signal processer for receiver are developed, By the use of this technique, one laser shot allows the determination of NO₂. concentraions with an un-certainty equivalent to 44 ppmΔX(m). It seems that the technique is most promising for a rangeresolved measurement of ambient molecular pollutants, because it has the advantage of cancelling the effect of atmospheric variation in a measurement when atmospheric aerosols are used as a distributed reflector.