Frost flowers and sea-salt aerosols over seasonal sea-ice areas in north-western Greenland during winter–spring
Keiichiro Hara1, Sumito Matoba2, Motohiro Hirabayashi3, and Tetsuhide Yamasaki41Department of Earth System Science, Faculty of Science, Fukuoka University 2Institute of Low Temperature Science, Hokkaido University 3National Institute of Polar Research, Tokyo, Japan 4Avangnaq, Osaka, Japan
Received: 05 Dec 2016 – Accepted for review: 12 Dec 2016 – Discussion started: 13 Dec 2016
Abstract. Sea-salts and halogens in aerosols, frost flowers and brine play an important role in atmospheric chemistry in polar regions. Simultaneous sampling and observations of frost flowers, brine, and aerosol particles were conducted around Siorapaluk in north-western Greenland during December 2013–March 2014. Results show that water-soluble frost flower and brine constituents were sea salts (e.g., Na+, Cl−, Mg2+, and Br−). Concentration factors of sea-salt constituents of frost flowers and brine relative to seawater were 1.14–3.67. Sea-salt enrichments of Mg2+, K+, Ca2+, and halogens (Cl−, Br−, and I) in frost flowers were associated with sea-salt fractionation by precipitation of mirabilite and hydrohalite. Aerosol number concentrations, particularly in coarse mode, were increased considerably by release from the sea-ice surface under strong wind conditions. Sulphate depletion by sea-salt fractionation was found to be slight in sea-salt aerosols because of heterogeneous SO42− formation on sea-salt particles. However, coarse and fine sea-salt particles were found to be rich in Mg. Strong Mg enrichment might be more likely to proceed in fine sea-salt particles. Mg-rich sea-salt particles might be released from the sea-ice surface and frost flowers. Mirabilite-like and ikaite-like particles were identified only in aerosol samples collected near new sea-ice areas.
Hara, K., Matoba, S., Hirabayashi, M., and Yamasaki, T.: Frost flowers and sea-salt aerosols over seasonal sea-ice areas in north-western Greenland during winter–spring, Atmos. Chem. Phys. Discuss., doi:10.5194/acp-2016-1094, in review, 2016.