Deposition of ionic species and black carbon to the Arctic snow pack: Combining snow pit observations with modeling

Abstract. Although aerosols in the Arctic have multiple and complex impacts on the regional climate, their removal due to deposition is still not well quantified. We combined meteorological, aerosol, precipitation, and snow pack observations with simulations to derive information about the deposition of sea salt components and black carbon (BC) from November 2011 to April 2012 to the Arctic snow pack at two locations close to Ny-Alesund, Svalbard. The dominating role of sea salt and the contribution of dust for the composition of atmospheric aerosols were reflected in the seasonal composition of the snow pack. The strong alignment of the concentrations of the major sea salt components in the aerosols, the precipitation, and the snow pack is linked to the importance of wet deposition for the transfer from the atmosphere to the snow pack. This agreement was less strong for monthly snow budgets and deposition indicating important relocation of the impurities inside the snow pack after deposition. Wet deposition was less important for the transfer of nitrate, non sea salt-sulfate, and BC to the snow during the winter period. The average BC concentration in the snow pack remains small with a limited impact on snow albedo and melting. Nevertheless, the observations also indicate an important redistribution of BC in the snowpack leading to layers with enhanced concentrations. The complex behavior of bromide due to modifications during the sea salt aerosol formation and remobilization in the atmosphere and in the snow were not resolved due to the lack of measurements in aerosols and precipitation.