Collective geographical ecoregions and precursor sources driving Arctic new particle formation

The Arctic is a rapidly changing ecosystem, with complex ice-ocean-atmosphere feedbacks. An important process is new particle formation (NPF), from gas-phase precursors, which provides a climate forcing effect. NPF has been studied comprehensively at different sites in the Arctic, ranging from those in the High Arctic and those at Svalbard to those in the continental Arctic, but no harmonised analysis has been performed on all sites simultaneously, with no calculations of key NPF parameters available for some sites. Here, we analyse the formation and growth of new particles from six long-term ground-based stations in the Arctic (Alert, Villum, Tiksi, Zeppelin Mountain, Gruvebadet, and Utqia;vik). Our analysis of particle formation and growth rates in addition to back-trajectory analysis shows a summertime maxima in the frequency of NPF and particle formation rate at all sites, although the mean frequency and particle formation rates themselves vary greatly between sites, with the highest at Svalbard and lowest in the High Arctic. The summertime growth rate, condensational sinks, and vapour source rates show a slight bias towards the southernmost sites, with vapour source rates varying by around an order of magnitudebetween the northernmost and southernmost sites. Air masses back-trajectories during NPF at these northernmost sites are associated with large areas of sea ice and snow, whereas events at Svalbard are associated with more sea ice and ocean regions. Events at the southernmost sites are associated with large areas of land and sea ice. These results emphasise how understanding the geographical variation in surface type across the Arctic is key to understanding secondary aerosol sources and providing a harmonised analysis of NPF across the Arctic.

Automated summary

The Arctic is undergoing rapid changes, including the formation of new particles from gas-phase precursors. Previous studies have examined the new particle formation (NPF) process at various Arctic sites, but there has been no coordinated analysis of all sites simultaneously. In this study, particle formation and growth rates were analyzed at six long-term ground-based stations in the Arctic. The results showed that NPF frequency and particle formation rates were highest at Svalbard and lowest in the High Arctic. The analysis also revealed variations in growth rates and vapor source rates between sites. The study emphasizes the importance of understanding geographical variations in surface types in order to fully understand NPF processes in the Arctic.