Drivers of aerosol variability in the high Arctic: insights from integrated observations at Gruvebadet and Zeppelin (Ny-Ålesund)

Abstract. This paper summarizes the main results from the scientific project “Boundary layer Evolution Through Harmonization of Aerosol measurements at Ny-Ålesund research stations” (BETHA-NyÅ), in which aerosol measurements of two Arctic atmospheric observatories located near Ny-Ålesund (Svalbard) at different elevations were harmonized: at the Gruvebadet atmospheric laboratory (61 m a.s.l.) and Zeppelin observatory (472 m a.s.l.). This approach allows for a better understanding of how atmospheric layering may affect the variability of aerosol observations in the Ny-Ålesund area. From February 2022 to March 2023, a coordinated sampling campaign enabled a direct comparison of optical, chemical, and physical aerosol properties, integrated with meteorological data from the Amundsen-Nobile Climate Change Tower. Results reveal a strong seasonal coherence between the two sites for two topical markers such as sulfate and ammonium, with clear evidence of the winter–spring Arctic Haze phenomenon. Local differences emerged mainly for biogenic tracers (e.g., arabitol and mannitol) which were detected at higher concentrations at Gruvebadet compared to Zeppelin observatory, highlighting the role of near-surface sources and aerosol stratification. The analysis of trace elements, lead isotopic ratios, and organic markers helped us to distinguish natural from anthropogenic contributions, confirming the dominant role of long-range transport and the persistence of isotopic signatures consistent with Eurasian sources. The systematic comparison across the two observatories demonstrates the robustness of the harmonized protocol and emphasizes the importance of an integrated monitoring network for evaluating the evolution of atmospheric processes in the Arctic.