Factors affecting the chemical composition of snowpack in the Kilpisjärvi area of North Scandinavia

Kilpisjärvi is a remote area in northwest Finland, almost without any local human impact on the environment. The design of the study was to investigate the chemical composition of local precipitation in the Kilpisjärvi region and determine the factors influencing it. To this aim, we collected 29 snow samples from the Lake Saana catchment and its surroundings in spring of 2008 and 2009. Already within the radius of a few hundred metres, significant chemical heterogeneity could be detected in the snow cover, caused by mixed marine and terrestrial precipitation and the impact of local rock dust. Based on the Cl−/Ca2+ ratio in snow, this could occur in localised areas, where marine or terrestrial aerosols predominate. Clear correlation was noted between SO42− and Ca2+, induced possibly by recombination of SO42− with carbonaceous dust. Other factors, such as nitrification in snow cover, could also have affected the pH levels of snow, which are mostly controlled by carbonate dust.