Comparison of Distributions of Atmospheric Gas Admixture Concentrations Measured by Remote and In Situ Instruments over the Russian Sector of the Arctic

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Data from aircraft and satellite sensing at the ocean–land boundary in the region of the Kara Sea in October 2014 are compared, using 11 and 7 profiles, which were synchronously measured over a continental part and ocean, respectively. It was found that the satellite usually overestimates the CH4 and CO2 concentrations in the 0–8-km layer over the continental part of the Arctic region and underestimates them over the ocean. Over continent, the satellite overestimates the methane concentrations by 28 ppb in the boundary layer and by much more in the middle (182 ppb) and upper (113 ppb) troposphere. Over ocean, the satellite measurements are, on average, lower by 37 ppb in the boundary layer, by 73 ppb in the middle troposphere, and by 71 ppb in the upper troposphere. Over continent, the discrepancy in CO2 concentrations, measured with different instruments, is, on average, 18.2 ppm in the boundary layer and can vary from 3.2 to 26.5 ppm. In the middle troposphere (4 km), the average differences decrease to 10.8 ppm, with the range of differences even increasing somewhat, to 0.6–25.5 ppm. In the upper troposphere (8 km), the average difference in measurements between the instruments decreases to 2.8 ppm. The underestimation turns out to be greater in amplitude over the ocean. It is noteworthy that the comparison yielded acceptable results for CO and O3.