Aerosol characteristics over the Arctic seas of Eurasia: results of measurements in 2018 and average spatial distribution in the summer-autumn periods of 2007–2018

Abstract

In August-September 2018, on the route of the expedition “Arctic-2018” (R/V “Akademik Tryoshnikov”) in the Arctic Ocean we carried out the following cycle of measurements of aerosol characteristics: aerosol optical depth (AOD) of the atmosphere in the wavelength range of 0.34–2.14 μm, number concentrations of particles with diameters of 0.4–10 μm, and mass concentration of absorbing substance (black carbon) in the near-ground layer. The optical and microphysical characteristics of aerosol were measured using portable sun photometer SPM, photoelectric particle counter AZ-10, and aethalometer MDA. Analysis of the measurements showed that aerosol and black carbon concentrations are maximal in the atmosphere of the Barents Sea and especially in its southern part, subject to outflows of fine aerosol from the north of Europe. The average aerosol characteristics near Kola Peninsula had been 7.2 cm–3 for aerosol concentration, 167 ng/m3 for black carbon concentration, and 0.16 for AOD (0.5 μm). To estimate the specific features of the spatial variations in aerosol over the Arctic seas of Russia, we generalized the measurements in nine (2007–2018) expeditions. All aerosol characteristics are found to decrease from west toward east in the average spatial distribution. The average concentrations of aerosol are 3.5 cm–3, black carbon concentrations are 41.2 ng/m3, and AOD (0.5 μm) values are 0.080 over the Barents Sea; and they decrease to 1.96 cm–3, 24.3 ng/m3, and 0.039 respectively over the East Siberian Sea. The decreasing tendency in the northeastern direction is noted in more detailed latitude-longitude distributions of aerosol characteristics in the atmosphere over the Barents and Kara Seas.