Ship-Borne Observations of Atmospheric CH 4 and δ 13 C Isotope Signature in Methane over Arctic Seas in Summer and Autumn 2021

• Published in: Atmosphere
• Main Authors: Natalia Pankratova, Andrey Skorokhod, Igor Belikov, Valery Belousov, Valeria Muravya, Mikhail Flint
• Format: Article in Journal/Newspaper
• Language: English
• Published: MDPI AG 2022
• Subjects: arctic methane; methane emissions; stable isotopes; Meteorology. Climatology; QC851-999; Arctic
• Online Access: https://doi.org/10.3390/atmos13030458; https://doaj.org/article/bcc83f4bad074ec98776fddda692a70f

Determining the sources of methane emissions in the Arctic remains a complex problem, due to their heterogeneity and diversity. Information on the amount of emissions has significant uncertainties and may differ by an order of magnitude in various literature sources. Measurements made in the immediate vicinity of emission sources help to clarify emissions and reduce these uncertainties. This paper analyzes the data of three expeditions, carried out in the western Arctic seas during Arctic spring, summer, and early autumn in 2021, which obtained continuous data on the concentration of methane and its isotope signature δ 13 C. CH 4 concentrations and δ 13 C displayed temporal and spatial variations ranging from 1.952 to 2.694 ppm and from −54.7‰ to −40.9‰, respectively. A clear correlation was revealed between the surface methane concentration and the direction of air flow during the measurement period. At the same time, even with advection from areas with a significant anthropogenic burden or from locations of natural gas mining and transportation, we cannot identify particular source of emissions; there is a dilution or mixing of gas from different sources. Our results indicate footprints of methane sources from wetlands, freshwater sources, shelf sediments, and even hydrates.