SAGE 2014: Spatial and Seasonal Variability in the Accumulation of Black Carbon and Soluble Ions in the Snow Pack in Northwest Greenland.

In April, 2014 members of the SAGE team conducted an oversnow traverse from Thule AFB to the vicinity of the NEEM drill site. One component of this campaign was investigating 37 shallow snowpits along the route to characterize stratigraphy and microphysics, and also to collect samples for chemical analyses. All of the pits were sampled continuously at 3 cm resolution to depths encompassing the most recent year of accumulation (spring 2013 to spring 2014). Selected pits were sampled continuously from the surface down to the layer corresponding to summer 2012, results presented will be restricted to the top year of all pits. Large differences in the annual accumulation and seasonal variations of black carbon and major ions were observed between the pits. Some of these gradients were expected, as the traverse route covered a large range in both distance from the coast and elevation. In addition, we find significant differences in accumulation of chemical impurities in some pits that were relatively close together, especially in the lower and steeper parts of the traverse route. We hypothesize that the combination of local topography and the tracks of individual snow storms create higher variability over small spatial scales along the slopes of the ice sheet compared to the interior.