Development of a Lidar System for Measuring Methane Using a Gas Correlation Method

We developed a laser long-path absorption lidar system using a gas correlation method for measuring atmospheric methane. This technique uses a broad-band laser and a gas correlation cell. We developed a potassium titanyl arsenate (KTA) optical parametric oscillator at 3.416 µm for the laser source. The optical round-trip path length is 20 m. The experiment was carried out using this system. It was estimated that the error in the density of methane is 4.4 ppm for measurement within 1 s.