日本地球惑星科学連合2019年大会

講演情報

[J] ポスター発表

セッション記号 M (領域外・複数領域) » M-IS ジョイント

[M-IS14] 南大洋・南極氷床が駆動する全球気候変動

2019年5月27日(月) 15:30 〜 17:00 ポスター会場 (幕張メッセ国際展示場 8ホール)

コンビーナ:関 宰(北海道大学低温科学研究所)、岡 顕(東京大学大気海洋研究所)、植村 立(琉球大学 理学部)、真壁 竜介(国立極地研究所)

[MIS14-P07] 東南極における大気硫酸の硫黄安定同位体組成の季節変動と大気硫黄循環への示唆

*石野 咲子1服部 祥平1Joel Savarino2Michel Legrand2Susanne Preunkert2Bruno Jourdain2Francis Albarede3Emmanuelle Albalat3吉田 尚弘1,4 (1.東京工業大学物質理工学院応用化学系、2.グルノーブル大学/CNRS、環境地球科学研究所、3.リヨン高等師範学校(LGL-TPE)、4.東京工業大学地球生命研究所)

キーワード:硫黄同位体分析、硫酸エアロゾル、南極

Atmospheric sulfate in Antarctica is produced mainly from a marine biogenic sulfur compound, dimethyl sulfide. They are therefore a subject of study related to the linkage between marine biogenic activity and climate. We investigate year-round observations of sulfur isotopic compositions of atmospheric sulfate (SO42) at inland (Dome C) and coastal (Dumont d’Urville) sites in East Antarctica to quantify the relative importance of marine biogenic (mb) and non-marine biogenic (nmb) SO42 for the Antarctic atmospheric sulfur cycle. The δ34S values of non-sea salt sulfate showed clear seasonal variations with summer maxima and winter minima, and showed homogeneity between inland and coastal sites throughout the year. This result suggests that the isotopic fractionation through chemical reactions during transportation from coastal to inland areas insignificantly affects the observed δ34Snss values. The observed δ34Snss values are controlled mainly by the relative importance of mb-SO42 and nmb-SO42. This finding, in conjunction with the SO42 records in Antarctic ice cores, will open a perspective implying the increased relative importance of nmb-SO42 during glacial periods. We also found a significant increase in nmb-SO42 concentrations in November, especially for the inland site. This nmb-SO42 increase is correlated with the 210Pb concentration, suggesting the existence of long-range transport of continental nmb-SO42 from lower latitudes to the Antarctic inland. Identification of the sources of those nmb-SO42 will be a key step for elucidation of the linkage between Antarctic atmosphere/climate and environmental changes at lower latitudes from the past through the future.