Spatial Distribution of Methane Concentration in Baikal Surface Water in the Spring Period

The results of describing the spatial distribution of methane concentration in the surface water of Lake Baikal in the spring are presented. The basis was the measurements of CH₄ content which were first carried out in the round-the-clock continuous mode along the entire route of the passage of research vessel in the complex expeditions of Limnological Institute, Siberian Branch, Russian Academy of Sciences, in the spring seasons of 2013, 2016, 2017, 2018, 2021, and 2022. Based on the results of six expeditions, a merged data array was compiled; it included 12 100 segments (with a step of 0.005° in latitude and 0.01° in longitude) which covered the total area 4466.7 km², or 14% of the surface of Lake Baikal. For a more detailed description of the spatial distribution of methane concentrations in surface water throughout the Baikal water area, the statistical characteristics were calculated in four zones: between 0 and 100 m, 100 and 200 m, 200 and 400 m, and over 400 m isobaths. The comparison of the methane concentrations in the analyzed array with the data of other researchers obtained in different years in nearby regions of the water area made it possible to conclude that the results presented in the work adequately reflect the most stable features of the spatial distribution of methane concentration in surface water of Lake Baikal in spring seasons.