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Abstract
Data collected since 1965 at a network of 9 stations in the northeastern United States show that precipitation is most acid in the growing season (May-September) and least acid in winter (December-February). For the Hubbard Brook station in New Hampshire, where the mean hydrogen ion content of precipitation ranges between 46 μeq/l in winter and 102 μeq/l in summer, the seasonal pattern in acidity correlates closely with seasonal differences in sulfur deposition from the atmosphere. As summer precipitation passes through the forest canopy, hydrogen ion concentrations are lowered by an average of 90 percent, primarily as a result of exchange with other cations. In winter the hydrogen ion content of incident precipitation is lowered from a mean of 50 μeq/l to a mean of 25 μeq/l during storage in the snowpack.
Parent Publication
Citation
Hornbeck, James W.; Likens, Gene E.; Eaton, John S. 1976. Seasonal patterns in acidity of precipitation and their implications for forest stream ecosystems. In: Dochinger, L. S.; Seliga, T. A., eds. Proceedings of the first international symposium on acid precipitation and the forest ecosystem; Gen. Tech. Rep. NE-23. Upper Darby, PA: U.S. Department of Agriculture, Forest Service, Northeastern Forest Experiment Station. 597-609
