Impact of Arctic Amplification variability on the chemical composition of the snowpack in Svalbard

Abstract. Arctic Amplification (AA) is leading to significant glacier ice melting, rapid sea ice decline, and alterations in atmospheric and geochemical processes in the Arctic regions, with consequences on the formation, transport, and chemical composition of aerosols and seasonal snowpack. Svalbard is particularly exposed to the AA, thus represents a relevant site in the Arctic to evaluate changes in local environmental processes contributing to the seasonal snow chemical composition. Sampling campaigns were conducted from 2018 to 2021 at the Gruvebadet Snow Research Site in Ny-Ålesund, in the North-West of the Svalbard Archipelago. During the investigated years, interannual variability of ionic and elemental impurities in surface snowpack has been associated to an alternation between relative warm years (2018–19, 2020–21), typical of the Arctic Amplification (AA) period, and relatively cold years (2019–20), more similar to the pre-AA conditions. Our results indicate that the concentration of impurities during the colder sampling season is strongly dependent on the production of sea spray related aerosol, likely deriving by a larger extension of sea ice, and drier, windy conditions. Our findings were therefore linked to the presence of sea ice in the Kongsfjorden in March 2020, and more generally around Spitsbergen, resulting from the exceptional occurrence of a strong and cold wintry stratospheric polar vortex and unusual AO index positive phase. By comparing the snow chemical composition of the 2019–20 season with 2018–19 and 2020–21, we present an overview of the possible impact of AA on the Svalbard snowpack, and the related change in the aerosol production process.