Japan Geoscience Union Meeting 2018

Presentation information

[EJ] Poster

A (Atmospheric and Hydrospheric Sciences) » A-AS Atmospheric Sciences, Meteorology & Atmospheric Environment

[A-AS06] Atmospheric Chemistry

Wed. May 23, 2018 1:45 PM - 3:15 PM Poster Hall (International Exhibition Hall7, Makuhari Messe)

convener:Yoko Iwamoto(Graduate School of Biosphere Science, Hiroshima University), Tomoki Nakayama(Graduate School of Fisheries and Environmental Sciences, Nagasaki University), Sakae Toyoda(東京工業大学物質理工学院, 共同), Nawo Eguchi(Kyushu University)

[AAS06-P26] Do hypohalous acids play important roles on sulfate formation in the Antarctic atmosphere?

*Sakiko Ishino1, Shohei Hattori1, Joel Savarino2, Qianjie Chen3, Jingyuan Shao3,4, Naohiro Yoshida1,5, Becky Alexander3 (1.School of Materials and Chemical Technology, Tokyo Institute of Technology, Japan, 2.Institut des Geosciences de l’Environnement, Universite Grenoble Alpes/CNRS, France, 3.Department of Atmospheric Sciences, University of Washington, USA, 4.Department of Atmospheric and Oceanic Sciences, School of Physics, Peking University, China, 5.Earth-Life Science Institute, Tokyo Institute of Tehcnology, Japan)

Keywords:Antarctica, Sulfate aerosols, Reactive bromine, 17O excess

Bry (= HBr + HOBr + Br2 + BrO + BrNO2 + BrNO3 + Br) is thought to play important roles in atmospheric chemistry in the Antarctic boundary layer through e.g., ozone destruction by Br atoms and oxidation of dimethyl sulfide by BrO [1,2]. A series of studies has indicated that a major source of Bry in coastal Antarctica is blowing-snow which takes a part of brine on the sea ice surface to the atmosphere [3,4]. Therefore, it has been suggested that the importance of Bry is limited at Dumont d’Urville (DDU; 66°40'S, 140°01'E), one of coastal Antarctic stations where the sea ice extent is relatively low compared to other coastal stations and highly exposed to the continental winds from the East Antarctic plateau [5]. Nevertheless, 17O-excess (Δ17O ≒ δ17O – 0.52 x δ18O) of atmospheric sulfate (SO42-) at DDU showed relatively low values in spring compared to autumn, which indicates the possibility of a significant contribution of hypohalous acids (HOBr, HOCl) to aqueous S(IV) oxidation in the spring time [6].
To test this hypothesis, we simulate 17O excess of SO42- using 3D chemical transport model (GEOS-Chem) in which reactions of S(IV) and hypohalous acids were recently implemented. We discuss the results by comparison of the observations at DDU with those from Concordia (75°06'S, 123°33'E), the inland Antarctic station which is located more than 1,000 km away from the sea ice.

[1] Saiz-Lopez et al. (2008), ACP, Vol.8, p.887-900, doi: 10.5194/acp-8-887-2008
[2] Read et al. (2008), ACP, Vol.8, p.2985-2997, doi: 10.5194/acp-8-2985-2008
[3] Yang et al. (2008), GRL, Vol.35, L16815, doi: 10.1029/2008GL034536
[4] Lieb-Lappen and Obbard (2015), ACP, Vol.15, p7537-7545, doi: 10.5194/acp-15-7537-2015
[5] Legrand et al. (2009), JGRA, Vo.114, D20, doi: 10.1029/2008JD011667
[6] Ishino et al. (2017), ACP, Vol.17, p.3713-3727, doi:10.5194/acp-17-3713-2017