A full year of aerosol size distribution data from the central Arctic under an extreme positive Arctic Oscillation: insights from the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) expedition

• Published in: Atmospheric Chemistry and Physics
• Main Authors: M. Boyer, D. Aliaga, J. B. Pernov, H. Angot, L. L. J. Quéléver, L. Dada, B. Heutte, M. Dall'Osto, D. C. S. Beddows, Z. Brasseur, I. Beck, S. Bucci, M. Duetsch, A. Stohl, T. Laurila, E. Asmi, A. Massling, D. C. Thomas, J. K. Nøjgaard, T. Chan, S. Sharma, P. Tunved, R. Krejci, H. C. Hansson, F. Bianchi, K. Lehtipalo, A. Wiedensohler, K. Weinhold, M. Kulmala, T. Petäjä, M. Sipilä, J. Schmale, T. Jokinen
• Format: Article in Journal/Newspaper
• Language: English
• Published: Copernicus Publications 2023
• Subjects: Physics; QC1-999; Chemistry; QD1-999; Arctic; Arctic Ocean; Norilsk; black carbon; norilsk; Sea ice; Siberia
• Online Access: https://doi.org/10.5194/acp-23-389-2023; https://doaj.org/article/792e28cf901f4e77932d77eceff41e00

The Arctic environment is rapidly changing due to accelerated warming in the region. The warming trend is driving a decline in sea ice extent, which thereby enhances feedback loops in the surface energy budget in the Arctic. Arctic aerosols play an important role in the radiative balance and hence the climate response in the region, yet direct observations of aerosols over the Arctic Ocean are limited. In this study, we investigate the annual cycle in the aerosol particle number size distribution (PNSD), particle number concentration (PNC), and black carbon (BC) mass concentration in the central Arctic during the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) expedition. This is the first continuous, year-long data set of aerosol PNSD ever collected over the sea ice in the central Arctic Ocean. We use a k -means cluster analysis, FLEXPART simulations, and inverse modeling to evaluate seasonal patterns and the influence of different source regions on the Arctic aerosol population. Furthermore, we compare the aerosol observations to land-based sites across the Arctic, using both long-term measurements and observations during the year of the MOSAiC expedition (2019–2020), to investigate interannual variability and to give context to the aerosol characteristics from within the central Arctic. Our analysis identifies that, overall, the central Arctic exhibits typical seasonal patterns of aerosols, including anthropogenic influence from Arctic haze in winter and secondary aerosol processes in summer. The seasonal pattern corresponds to the global radiation, surface air temperature, and timing of sea ice melting/freezing, which drive changes in transport patterns and secondary aerosol processes. In winter, the Norilsk region in Russia/Siberia was the dominant source of Arctic haze signals in the PNSD and BC observations, which contributed to higher accumulation-mode PNC and BC mass concentrations in the central Arctic than at land-based observatories. We also show that the wintertime ...