Continuously tunable ir lidar with applications to remote measurements of SO(2) and CH(4).

Remote atmospheric measurements of SO(2) and CH(4) were performed using a differential absorption lidar with a continuously tunable LiNbO(3) parametric oscillator and amplifier source in the 1.4-4.0-microm region. A comparison of injected gas concentration in a remotely located sample chamber showed excellent agreement with a SO(2) detection sensitivity of 0.9 ppm-km. An ambient level measurement of methane at the 1.66-microm overtone transition gave 3.9 +/- 0.7 ppm Performance predictions indicate an order of magnitude gain in sensitivity is possible with recently demonstrated tunable source improvements. The wide tuning range capability allows the measurement of numerous other pollutant molecules in the 1.4-4.0-microm region.