© Author(s) 2009. This work is distributed under the Creative Commons Attribution 3.0 License. The Cryosphere

Abstract. The chemistry of snow and ice cores from Sval-bard is influenced by variations in local sea ice margin and distance to open water. Snow pits sampled at two summits of Vestfonna ice cap (Nordaustlandet, Svalbard), exhibit spa-tially heterogeneous soluble ions concentrations despite sim-ilar accumulation rates, reflecting the importance of small-scale weather patterns on this island ice cap. The snow pack on the western summit shows higher average values of ma-rine ions and a winter snow layer that is relatively depleted in sulphate. One part of the winter snow pack exhibits a [SO2−4 /Na+] ratio reduced by two thirds compared with its ratio in sea water. This low sulphate content in winter snow is interpreted as the signature of frost flowers, which are formed on young sea ice when offshore winds predominate. Frost flowers have been described as the dominant source of sea salt to aerosol and precipitation in ice cores in coastal Antarctica but this is the first time their chemical signal has been described in the Arctic. The eastern summit does not show any frost flower signature and we interpret the unusu-ally dynamic ice transport and rapid formation of thin ice on the Hinlopen Strait as the source of the frost flowers.