Variability of methane concentration in the Arctic atmosphere from shipborne measurements in 2023

Arctic temperatures have in recent decades risen faster than the global average, threatening the large carbon pools locked in the Arctic permafrost. Atmospheric composition monitoring has become a priority, but it is extremely difficult to set up in such remote regions, especially over the Arctic seas. These observations are limited by the length of the navigation season and the logistical difficulties of sampling and measuring atmospheric composition. In this study, atmospheric CH₄ concentrations were measured over 28 days in the fall and early winter of 2023. The main study areas were the Barents Sea and the southern regions of the Kara Sea, with special attention paid to the bays of the western coast of the Novaya Zemlya archipelago. During the study period, atmospheric CH₄ concentrations ranged from 2.018 to 2.122 ppm, with an average value of 2.039 ± 0.013 ppm.

Variations in atmospheric CH₄ in the surface layer were mainly due to meteorological conditions, as well as the geographical location of the vessel and the time of measurements. High-resolution coupled measurements of marine and atmospheric CH₄ data are critical for understanding the scale of methane emissions at the ocean-atmosphere interface, especially in winter when the mixing layer increases, convection intensifies, and more methane from the water column can enter the atmosphere. In addition, our data can be used as input parameters for climate models.