[A-AS04] 大気化学

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

*森 樹大¹、東 久美子^2,3、近藤 豊²、塚川 佳美²、三浦 和彦¹、平林 幹啓²、大島 長⁴、小池 真⁵、Kaarle Kupiainen⁶、茂木 信宏⁵、大畑 祥⁷、Sinha Ram⁸、杉浦 幸之助⁹、青木 輝夫¹⁰、Martin Schneebeli¹¹、Konrad Steffen¹¹、佐藤 篤司¹²、對馬 あかね¹³、Vladimir Makarov¹⁴、大宮 哲^15,16、杉本 敦子¹⁷、鷹野 真也¹⁷ (1.東京理科大学、2.国立極地研究所、3.総合研究大学院大学、4.気象研究所、5.東京大学大学院、6.Environmental Protection Department Ministry of the Environment、7.名古屋大学、8.Department of Space Indian Space Research Organization、9.富山大学、10.岡山大学、11.WSL Institute for Snow and Avalanche Research、12.防災科学技術研究所、13.総合地球環境学研究所、14.Melnikov’s Permafrost Institute、15.北海道大学低温科学研究所、16.寒地土木研究所、17.北海道大学)

キーワード：ブラックカーボン、湿性除去、北極

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.