The impact of blowing snow above sea ice on atmospheric ice nucleating particles in the Central Arctic

Abstract. Ice nucleating particles (INPs) in the Central Arctic contribute to local climate feedback mechanisms through their impacts on cloud radiative properties and formation. Despite their importance, the contributions of local and remote aerosol sources to Arctic INP populations are currently poorly understood. One potential source of INPs during winter and spring is the sublimation of snow particles during blowing snow events (BSEs) over sea ice, which could constitute a significant local source in an otherwise remote region. We investigated the impact of BSEs on Central Arctic INPs using year-round observations taken during the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) campaign from October 2019 to October 2020. Based on our observations of atmospheric INP and surface snow samples as well as their major ion composition we did not find an impact of BSEs on INP concentrations, but we did observe an increase in INP activation temperatures. Additionally, we found overlapping INP activation temperatures in both surface snow and aerosol, and observed that BSEs brought the enrichment factors of SO₄^2-, K⁺, and Br^- with respect to Na⁺ closer to those observed in surface snow, indicating that sublimating snow is a source of non-sea-salt aerosol. However, our analysis also indicates contributions from long-range transportation during BSEs. We conclude that aerosol populations during BSEs are influenced by a case-dependant combination of sublimating snow and long-range transportation, and we recommend that further work at a higher temporal resolution is needed to fully understand the impact of BSEs on INPs.