Remote sensing of atmospheric methane with IR OPO lidar system

Abstract

A differential absorption lidar (DIAL) system designed on the basis of optical parametric oscillators (OPO)with nonlinear KTiOAsO4 (KTA) and KTiOPO4 (KTP) crystals is described. The crystals allow laser radiation tuning in the infrared region (IR) wavelength region. The measurements in the 3.30-3.50 μm spectral range, which includes a strong absorption band of methane, are carried out. Lidar backscattered signals in the spectral band 3.30-3.50 μm has been measured and analyzed along the horizontal path in the atmosphere. Based on the experimental results, CH4 concentrations ~2.085 ppm along a 800 m surface path are retrieved in the spectral range under study with a spatial resolution of 100 m.