[A-CG50] Biogeochemical linkages between the surface ocean and atmosphere

[ACG50-10] Seasonal variations in the sources of atmospheric organic aerosols in northern Greenland

*Yuzo Miyazaki¹, Eri Tachibana¹, Yutaka Kurosaki^1,2,3, Sumito Matoba¹ (1.Institute of Low Temperature Science, Hokkaido University, 2.Graduate School of Environmental Science, Hokkaido University, 3.Graduate School of Environmental Studies, Nagoya University)

Keywords:Marine atmospheric organic aerosol, Greenland, Sea ice melting, Biogeochemical linkage between the atmosphere and the ocean

Organic aerosol (OA) is one of the most abundant fractions of the submicrometer aerosol mass and plays an important role in modulating the radiation balance of the sensitive Arctic atmosphere. However, the sources and formation processes of OAs in the Arctic have yet to be well understood. In order to reveal the annual cycles in the relative contributions of anthropogenic and biogenic sources to OAs in the Arctic region, we made continuous aerosol sampling and off-line chemical analysis of submicrometer OAs and relevant chemical parameters in Siorapaluk in northern Greenland during 2021–2023. We show that organic matter was the dominant component of submicrometer aerosols from spring to autumn, where water-soluble fraction (70%) was dominant. In spring, OA in the Arctic is dominated by marine biogenic secondary sources associated with phytoplankton bloom in the North Atlantic and the North Water Polynya. These OAs include oxidation products of dimethyl sulfide (DMS) and α-pinene. In winter, the observed OA is dominated by anthropogenic emissions, which consist of both direct combustion emissions and long-range transported aerosols. During the summer and autumn period, both terrestrial biogenic sources and marine sources contributed to the observed OAs. The seasonality of the different source contribution to the submicrometer OAs has the potential to modify the cloud condensation nuclei properties as well as ice-nucleating particles.