25 Oct 2022
25 Oct 2022
Status: this preprint is currently under review for the journal ACP.

Disentangling methane and carbon dioxide sources and transport across the Russian Arctic from aircraft measurements

Clément Narbaud1, Jean-Daniel Paris1,2, Sophie Wittig1, Antoine Berchet1, Marielle Saunois1, Philippe Nédelec3, Boris D. Belan4, Mikhail Y. Arshinov4, Sergei B. Belan4, Denis Davydov4, Alexander Fofonov4, and Artem Kozlov4 Clément Narbaud et al.
  • 1Laboratoire des Sciences du Climat et de l’Environnement, IPSL, Orme des Merisiers, CEA-CNRS-UVSQ, 91190 Gif-sur-Yvette, France
  • 2Climate and Atmosphere Research Centre (CARE-C), The Cyprus Institute, Nicosia, 2121, Cyprus
  • 3LAERO, Université de Toulouse, UT3, CNRS, IRD, Toulouse, France
  • 4independent researcher

Abstract. A more accurate characterization of the sources and sinks of methane (CH4) and carbon dioxide (CO2) in the vulnerable Arctic environment is required to better predict climate change. A large-scale aircraft campaign took place in September 2020 focusing on the Siberian Arctic coast. CH4 and CO2 were measured in situ during the campaign and form the core of this study. Measured ozone (O3) and carbon monoxide (CO) are used here as tracers. Median CH4 mixing ratios are fairly higher than the monthly mean hemispheric reference (Mauna Loa, Hawaii, US) with 1890–1969 ppb vs 1887 ppb respectively, while CO2 mixing ratios from all flights are lower (408.09–411.50 ppm vs 411.52 ppm). We also report on three case studies. Our analysis suggests that during the campaign the European part of Russia’s Arctic and Western Siberia were subject to long-range transport of polluted air masses, while the East was mainly under the influence of local emissions of greenhouse gases. The relative contributions of the main anthropogenic and natural sources of CH4 are simulated using the Lagrangian model FLEXPART in order to identify dominant sources in the boundary layer and in the free troposphere. In western terrestrial flights, air masses composition is influenced by emissions from wetlands and anthropogenic activities (waste management, fossil fuel industry and to a lesser extent the agricultural sector), while in the East, emissions are dominated by freshwaters, wetlands, and the oceans, with a likely contribution from anthropogenic sources related to fossil fuels. Our results highlight the importance of the contributions from freshwater and oceans emissions. Considering the large uncertainties associated to them, our study suggests that the emissions from these aquatic sources should receive more attention in Siberia.

Clément Narbaud et al.

Status: open (until 06 Dec 2022)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on acp-2022-720', Anonymous Referee #1, 24 Nov 2022 reply
  • RC2: 'Comment on acp-2022-720', Anonymous Referee #2, 25 Nov 2022 reply

Clément Narbaud et al.

Clément Narbaud et al.


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Short summary
We reported aircraft measurements of methane and other greenhouse gases concentrations across Siberia and used a numerical model to determine the contributions of the different methane sources. We investigated 47 vertical profiles to better characterize methane emissions in this imperfectly known region that has a serious impact on global carbon budget. Methane emissions in western regions were mostly induced by human activities, while emissions in the east were dominated by natural sources.