Atmospheric CO 2 and CH 4 Fluctuations over the Continent-Sea Interface in the Yenisei River Sector of the Kara Sea

• Published in: Atmosphere
• Main Authors: Alexey Panov, Anatoly Prokushkin, Igor Semiletov, Karl Kübler, Mikhail Korets, Ilya Putilin, Anastasiya Urban, Mikhail Bondar, Martin Heimann
• Format: Article in Journal/Newspaper
• Language: English
• Published: MDPI AG 2022
• Subjects: climate; Arctic; Siberia; atmospheric composition; carbon dioxide; methane; Meteorology. Climatology; QC851-999; Arctic Ocean; Kara Sea; Yenisei River; permafrost; Taimyr; Tundra
• Online Access: https://doi.org/10.3390/atmos13091402; https://doaj.org/article/1f42b331d2e74c5aaff38e4d3cd93a76

Observations of the atmospheric sources and sinks of carbon dioxide (CO 2 ) and methane (CH 4 ) in the pan-Arctic domain are extremely scarce, limiting our knowledge of carbon turnover in this climatically sensitive environment and the fate of the enormous carbon reservoirs conserved in the permafrost. Especially critical are the gaps in the high latitudes of Siberia, covered by the vast permafrost underlain tundra, where only several atmospheric monitoring sites are operational. This paper presents the first two years (September 2018–January 2021) of accurate continuous observations of atmospheric CO 2 and CH 4 dry mole fractions at the recently deployed tower-based measurement station “DIAMIS” (73.5068° N, 80.5198° E) located on the southwestern coast of the Taimyr Peninsula, Siberia, at the Gulf of the Yenisei River that opens to the Kara Sea (Arctic Ocean). In this paper, we summarized the scientific rationale of the site, examined the seasonal footprint of the station with an analysis of terrestrial vegetation and maritime sector contributing to the captured atmospheric signal, and illustrated temporal patterns of CO 2 and CH 4 for the daytime mixed atmospheric layer over the continent–sea interface. Along with the temporal variations reflecting a signal caused pan-Arctic and not very much influenced by the local processes, we analyzed the spatiotemporal distribution of the synoptic anomalies representing the atmospheric signatures of regional sources and sinks of CO 2 and CH 4 for the studied high-arctic Siberian domain of ~625 thousand km 2 , with nearly equal capturing the land surface (54%) and the ocean (46%) throughout the year. Both for CO 2 and CH 4 , we have observed a sea–continent declining trend, presuming a larger depletion of trace gases in the maritime air masses compared to the continental domain. So far, over the Kara Sea, we have not detected any prominent signals of CH 4 that might have indicated processes of subsea permafrost degradation and occurrence of cold seeps–still mainly observed ...