Mobile mid-infrared differential absorption lidar for methane monitoring in the atmosphere: Calibration and first in situ tests

Abstract

A mobile infrared (IR) differential absorption lidar designed for the study of methane in the atmosphere is described. A mobile IR radiation source for the differential absorption lidar was calibrated in the informative range for methane sounding near ∼3400 nm. Informative methane sounding wavelengths for mid-latitude summer conditions are 3428.428 nm (on-line) and 3431.708 nm (off-line), respectively. The maximum output energy in a pulse of the mobile lidar is 4.3 mJ (for on-line wavelength) and 2.5 mJ (for off-line wavelength). The lidar was in situ tested in recording the atmospheric response at calibrated sounding wavelengths and in retrieving background methane concentrations of ∼2.0 ppm along surface atmospheric sounding paths. The test results at the Basic Experimental Complex and the Fonovaya Observatory of IAO SB RAS are presented.

Keywords

• Lidar
• Infrared region
• Differential absorption
• Atmosphere
• Methane