Increased aerosol concentrations in the High Arctic attributable to changing atmospheric transport patterns

Abstract

The Arctic environment has changed profoundly in recent decades. Aerosol particles are involved in numerous feedback mechanisms in the Arctic, e.g., aerosol-cloud/radiation interactions, which have important climatic implications. To understand changes in different Arctic aerosol types and number concentrations, we have performed a trend analysis of particle number size distributions, their properties, and their associated air mass history at Villum Research Station, northeastern Greenland, from 2010 to 2018. We found that, during spring, the total/ultrafine mode number concentration and the time air masses spent over the open ocean is significantly increasing, which can be ascribed to transport patterns changing to more frequent arrival from the ice-free Greenland Sea. We found that, during summer, the total/ultrafine mode number concentration, the occurrence of the Nucleation cluster (i.e. newly formed particles from gas to particle conversion), and the time air masses spent over the open ocean is significantly increasing. This can also be attributed to changing transport patterns, here with air masses arriving more frequently from Baffin Bay. Finally, we found that, during autumn, the ultrafine number concentration and the occurrence of the Pristine cluster (i.e. clean, natural Arctic background conditions) is significantly increasing, which is likely due to increasing amounts of accumulated precipitation along the trajectory path and decreasing time air masses spent above the mixed layer, respectively. Our results demonstrate that changing circulation and precipitation patterns are the factors predominantly affecting the trends in aerosol particle number concentrations and the occurrence of different aerosol types in northeastern Greenland.

A full year of aerosol size distribution data from the central Arctic under an extreme positive Arctic Oscillation: Insights from the MOSAiC expedition

“…In general, the particles >100 nm in diameter originate from anthropogenic sources, where the secondary processes contribute to smaller particles. Overall, the annual cycle in the PNSD data presented here agrees with previous studies of the seasonality of Arctic aerosol from land-based sites (Tunved et al, 2013;Freud et al, 2017;Croft et al, 2016;Pernov et al, 2022;Dall'Osto et al, 2018;Lange et al, 2018). In winter, we observed elevated accumulation mode aerosol, or Arctic Haze, dominated by anthropogenic sources in Russia/Siberia, namely the Norilsk smelter region.…”

“…These clusters are generally similar to previous cluster results from other Arctic stations(Dall'Osto et al, 2017;Pernov et al, 2022). The differences mainly arise from different periods, different size ranges, different temporal aggregation, and the fact that landbased stations are stationary while Polarstern drifted in the central Arctic Ocean.…”

“…These cold air masses during this time of year have low moisture content, and the stability of the atmosphere remains intact due to such low temperatures, which limits both wet and dry depositional processes (Shaw, 1995;Garrett et al, 2011). While we do not assess precipitation during transport in this study, others have shown that precipitation amounts are higher in summer than in winter/spring during air mass transport from lower latitudes to the Arctic (Barrie, 1986;Freud et al, 2017;Pernov et al, 2022). Therefore, transport of anthropogenic emissions from lower latitudes is possible, as particulate pollution has longer lifetimes under cold, dry, and stable conditions (Bradley et al, 1993).…”

“…(2001-2017, aethalometer). eBC data from Villum, Greenland between 2018 -2020 were obtained using an Aethalometer, as detailed in Thomas et al (2022). For details on the measurements of the eBC and elemental carbon mass, we refer to Schmale et al (2022).…”

“…Globally, aerosol and cloud processes lead to a net cooling that opposes greenhouse gas warming (e.g., IPCC, 2021), however, aerosol-cloud interactions in the Arctic can lead to a warming effect that is comparable in magnitude to the warming associated with greenhouse gases, depending on the season (Lubin and Vogelmann, 2006). These aerosol-cloud interactions are sensitive to the presence of aerosols, which are known to exhibit a strong seasonal dependence in the Arctic (e.g., Lange et al, 2018;Schmale et al, 2022;Pernov et al, 2022).…”