Spatial and Temporal Variability of Surface Snowfall and Snowpack Chemistry in Central Ontario

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Abstract
The physical and chemical structure of the snowpack near North Bay, Ontario was examined during the winter of 1984. precipitation chemistry measurements were also made. A marked areal uniformity was noted in the layered structure of the snowpack and in the vertical variation of the chemical composition. In late January, pH values of the snowpack varied from ∼4.1 at the surface to ∼4.8 near the ground. After rain and a major thaw in February the pH was near 4.8 throughout. Nitrate concentrations exceeded those of sulfate in the snowpack. The molar concentration ratio of / was typically 0.5. Samples of precipitation from six sites had pH values ranging from 3.4 to 5.2. to equivalent ratios were 1 in rain. The chemical composition of the precipitation was closely related to the airmass trajectory. Southerly trajectories yielded the lowest pH values and highest pollutant concentrations. The one-month period from 20 January to 21 February had a deposition of 0.2 g m−2 and a deposition of 0.35 g m−2. For , this deposition would be about one-twelfth the expected annual deposition and for about one-fifth.