Intercomparison of snow Sampling and Analysis Within the Alpine-Wide Snowpack Investigation (SNOSP)

In order to investigate the seasonal and geographical distribution of snow concentrations anddeposition fluxes of environmentally relevant ionic species in the Alps, the international programSNOSP was initiated. In the framework of this program, intercomparisons of snow samplingtechniques and analytical methods to determine the ionic species C1^-, NO ₃ ^- ,SO ₄ ^2- , K⁺, Na⁺, NH4 ⁺, Mg²⁺, and Ca²⁺, as well as the pH and the specificconductivity were performed. The concentrations of these species in the snow samples collectedin the SNOSP program varied by orders of magnitude with, e.g., concentrations of NO ₃ ^- , SO ₄ ^2- , and NH4 ⁺ ranging from 0.2-60, 0.2-90, and 0.1-60 µeq L^-1,respectively. The intercomparisons revealed a reasonable agreement of the determinations of thespecies Cl^-, NO ₃ ^- , SO ₄ ^2- , Na⁺, and NH4 ⁺ in snow. Results were less satisfactory for K⁺, Mg²⁺, Ca²⁺,and H⁺, mainly due to the very low concentrations. In conclusion, recommendations areformulated for the reliable derivation of chemical inventories from snow packs.