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Abstract

Glaciochemical studies at midlatitudes promise to contribute significantly to the understanding of the atmospheric cycling of species with short atmospheric lifetimes. Here we present results of chemical analyses of environmentally relevant species performed on an ice core from Fiescherhorn glacier, Swiss Alps (3890 m above sea level). This glacier site is unique since it is located near the high-alpine research station Jungfraujoch. There long-term meteorological and air quality measurements exist, which were used to calibrate the paleodata. The 77-m-long ice core was dated by annual layer counting using the seasonally varying signals of tritium and 15•80. It covers the time period 1946-1988 and shows a high net accumulation of water of 1.4 m yr-• allowing for the reconstruction of high-resolution environmental records. Chemical composition was dominated by secondary aerosol constituents as well as mineral dust components, characterizing the Fiescherhorn site as a relatively unpolluted continental site. Concentrations of species like ammonium, nitrate, and sulfate showed an increasing trend from 1946 until about 1975, reflecting anthropogenic emission trends in western Europe. For mineral dust tracers, no trends were obvious, whereas chloride and sodium showed slightly higher levels from 1965 until 1988, indicating a change in the strength of sea-salt transport. Good agreement between the sulfate paleorecord with direct atmospheric measurements was found (correlation coefficient r2=0.41). Thus a "calibration" of the paleorecord over a significant period of time could be conducted, revealing an average scavenging ratio of 180 for sulfate.