[A-AS04] Atmospheric Chemistry

[AAS04-09] Black Carbon and Inorganic Aerosols in Snowpack over the Arctic

*Tatsuhiro Mori¹, Kumiko Goto-Azuma^2,3, Yutaka Kondo², Yoshimi Ogawa-Tsukagawa², Kazuhiko Miura¹, Motohiro Hirabayashi², Naga Oshima⁴, Makoto Koike⁵, Kaarle Kupiainen⁶, Nobuhiro Moteki⁵, Sho Ohata⁷, Sinha Puna Ram⁸, Konosuke Sugiura⁹, Teruo Aoki¹⁰, Martin Schneebeli¹¹, Konrad Steffen¹¹, Atsushi Sato¹², Akane Tsushima¹³, Vladimir Makarov¹⁴, Satoshi Omiya^15,16, Atsuko Sugimoto¹⁷, Shinya Takano¹⁷ (1.Tokyo University of Science, 2.National Institute of Polar Research, 3.The Graduate University for Advanced Studies, 4.Meteorological Research Institute, 5.Depertment of Earth and Planetary Science, Graduate School of Science, The University of Tokyo, 6.Environmental Protection Department Ministry of the Environment, 7.Institute for Space–Earth Environmental Research (ISEE), Nagoya University, 8.Department of Space Indian Space Research Organization, 9.University of Toyama, 10.Okayama University, 11.WSL Institute for Snow and Avalanche Research, 12.former Snow and Ice Research Center, 13.Reserach Institute for Humanity and Nature, 14.Melnikov’s Permafrost Institute, 15.Institute of Low Temperature Science, Hokkaido University, 16.Civil Engineering Research Institute for Cold Region, 17.Graduate School of Environmental Science, Hokkaido University)

Keywords:Black carbon, Wet deposition, Arctic

Black carbon (BC) deposited on snow lowers snow albedo, potentially contributing to the warming in the Arctic. The distributions of inorganic aerosols (ions), which contribute to direct and indirect aerosol effects, are also greatly influenced by deposition. It is critically important to measure the spatial distributions of BC and ions in snowpack in different regions of the Arctic to quantify these effects. Because accurate measurements of BC and ions in snowpack are very limited, we measured the mass concentrations of size-resolved BC (C_MBC) and ions in snowpack over Finland, Alaska, Siberia, Greenland, and Spitzbergen in early spring during the period of 2012 – 2016 by using a single-particle soot photometer and ion chromatography, respectively. BC deposition amounts (DEP_MBC) during snow accumulation periods were derived from C_MBC and snow water equivalent (SWE). Detailed analyses have shown that the spatial distributions of the anthropogenic BC flux and topography strongly influenced the latitudinal variations of C_MBC and BC size distributions. The average size distributions of BC in snowpack shifted to smaller sizes with the decrease in C_MBC, likely due to an increase in the removal efficiency of BC with the increase in BC diameter during transport from major BC sources. The present C_MBC were much lower than previous C_MBC measured by using an Integrating Sphere/Integrating Sandwich spectrophotometer by a factor of about 13. The present accurate data of C_MBC, SWE, and DEP_MBC are very useful in constraining climate model to estimate the effect of BC on the climate of the Arctic.