On a Method for Measuring Methane Concentration on Extended Atmospheric Paths Using a Remote Gas Analyzer with a Powerful Raman Amplifier

Resumo

Abstract—The paper presents the results of methane concentration measurements on extended horizontal and vertical paths in the Earth’s atmosphere using a laser-generated remote gas analyzer based on a two-stage Raman amplifier with an output power of about 3 W in quasi-continuous mode with linear-frequency modulation of the laser and distributed feedback. An empirical expression of the weight function for anomalous gas distribution is obtained with a maximum concentration at a height of ~700 m and an anomalously low concentration at heights above 1000 m. This distribution agrees well with the experimental data obtained for a situational plan with additional methane emission sources. During measurements, the water absorption line was detected, which strongly depends on atmospheric humidity and can be used to refine weather data and ecological conditions.