Methane Concentration and δ13C Isotopic Signature in Methane over Arctic Seas in Summer and Autumn 2020

• Published in: Oceanology (Washington. 1965) 2022-12, Vol.62 (6), p.757-764
• Main Authors: Pankratova, N. V., Belikov, I. B., Skorokhod, A. I., Belousov, V. A., Muravya, V. O., Flint, M. V., Berezina, E. V., Novigatsky, A. N.
• Format: Article
• Language: English
• Subjects: Autumn; Earth and Environmental Science; Earth Sciences; Emission measurements; Emissions; Expeditions; Isotopes; Marine Chemistry; Methane; Multiship expeditions; Northern Hemisphere; Oceanography; Summer
• ISSN: 0001-4370; 1531-8508
• DOI: 10.1134/S0001437022060108

We have studied the assessment of methane content in the near atmospheric layer of the Arctic seas and the sources of its emissions. Continuous atmospheric measurements of methane concentration and δ 13 C isotope signature in methane were carried out during two expeditions aboard the R/V Akademik Mstislav Keldysh in the summer and autumn of 2020. The minimum CH 4 concentration (mean 1.937 ± 0.010 ppm) were obtained over the North and Norwegian Seas. The maximum CH 4 concentration took place above the Kara (1.998 ± 0.030 ppm on average, maximum values are up to 2.000–2.040 ppm) and White (2.006 ± 0.030 ppm on average) seas. The average values of δ 13 C in the studied region were close to that typical for the Northern Hemisphere: –47.5‰. Regional changes in δ 13 C allowed CH 4 sources to be identified and showed that the methane concentration in the surface atmospheric level is mainly affected by the direction of air-mass advection.