CHEMICAL-SPECIES SPATIAL-DISTRIBUTION AND RELATIONSHIP TO ELEVATION AND SNOW ACCUMULATION RATE OVER THE GREENLAND ICE-SHEET

Major chemical species (Cl-, NO3-, SO42-, Na+, K+, Mg2+, Ca2+) from 24 snowpits (sampled at a resolution of 3 cm, total 2995 samples) collec ted from northern, central, and southern Greenland were used for this investigation. The annual and seasonal (winter and summer) concentrati on of each chemical species was calculated and used to study the spati al distribution of chemical species over the central portion of the Gr eenland Ice Sheet. A two-sided t-distribution test (alpha=0.05) sugges ts that concentrations of major chemical species in snow do not vary s ignificantly over this portion of central Greenland. The relationship between chemical concentration and snow accumulation rate was investig ated using annual data from two groups of snowpits: those from coastal sites (northern and southern Greenland); and those from high-altitude inland sites (central Greenland). The snowpit data from a single grou p, when examined independently of the other group, show that chemical concentrations do not vary with snow accumulation rate. However, when data from the two groups are integrated into a single data set, pseudo relationships appear, with NO3- concentration decreasing and Na+, K+, Mg2+, and Cl- increasing as snow accumulation rate increases. Therefor e we suggest that it is improper to study the relationship between che mical concentration and snow accumulation rate by using data collected from different geographic sites. The relationship between elevation a nd chemical concentration was investigated using the same suite of ann ual data sets. We find that Cl-, Na+, and Mg2+ concentrations decrease , while NO3- concentration increases, with increasing elevation on the Greenland Ice Sheet.