Concentration and Isotopic Composition of Methane, Associated Gases, and Black Carbon over Russian Arctic Seas (Shipborne Measurements).

In Russian Arctic seas, observations of surface methane concentrations (CH₄), ozone, nitrogen and carbon oxides, as well as the content of isotope and black carbon (BC, soot aerosol), were carried out from onboard of the R/V Academician Mstislav Keldysh. The areas of local methane releasing from bottom sediments were investigated. It was shown that the studied methane releasing on the Arctic shelf are of a local nature and, on the whole, insignificantly affect the composition of the atmosphere in the region. The average concentration of methane in the surface air in the Arctic seas is mainly determined by large-scale processes of air mass transfer. An analysis of the distribution of black carbon along the route of the vessel was carried out. It was found that the excess in the concentration of black carbon over the background values is observed occasionally during advection of air masses from the mainland and from the areas of associated gases burning and forest fires. The effect of emissions from a ship's chimney on the data obtained was analyzed. [ABSTRACT FROM AUTHOR]