Laser remote sensing of atmospheric temperature by observing resonant absorption of oxygen

A dual-frequency system is used to demonstrate the measurement of atmospheric temperature, through laser energy absorption monitoring at the center of an O2 resonant absorption line near 770 nm. It is shown that the average temperature of a 1 km path can be determined within 1.0 C, with a noise level of 0.3 C. An iterative algebraic expression for this method was developed, and is shown to be applicable in the troposphere; the effects of pressure and humidity on temperature determination were made clear by the algorithm and found to be small near the earth's surface.