Seasonal variations of pH and electrical conductivity in a snow-firn pack on Glacier No. 1, eastern Tianshan, China
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Analyses of pH and electrical conductivity (EC) in surface snow and snow-firn pack samples collected successively in a weekly basis during September 2002 to September 2004 on the east branch of Glacier No. 1, eastern Tianshan, China is presented. pH and EC in surface snow show obvious seasonal variations. pH and EC values are high in spring and early summer, and they are low in late summer; moreover, pH value indicates more and less alkalinity in spring and winter, respectively. In addition, both pH and EC peaks strongly coincide with the corresponding period of greatest NE and ENE wind velocity. After deposition, pH and EC in snow-firn pack display diverse features and seasonal trends, which correlate with snow compaction, dry deposition, precipitation and temperature, and so on.
Furthermore, both pH and EC peaks occur above dust layers, and are adjacent to dust layers in some snow-firn packs. This implies that dust layers may have an influence on the elution process of soluble ions. In addition, linear correlation analyses among major chemical species (Na+, K+, Ca2+, Mg2+, NH4+, Cl−, SO42−, NO3−, pH and EC) in surface snow indicate that Ca2+ is the key ion determining pH and EC in the study area.
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