Nitrate ion in Antarctic firn as a marker for solar activity

This paper presents the first comparison of nitrate ion (NO sub(3) super(-) ) concentrations in firn cores collected from South Pole (1978-1979) and Vostok (1979-1980) stations, covering a continuous sequence of similar to 1200 yr. Previous reports have focused primarily upon the limited data exclusively from South Pole collections, i.e., Parker et al (1977, 1978), Parker and Zeller (1980), Rood et al (1979), Stothers (1980), and Zeller and Parker (1979, 1981). Firn cores were obtained from two locations on the East Antarctic ice sheet by using dry, open hole drilling in consecutive summers by the Polar Ice Coring Office of the University of Nebraska. The first core was drilled to a depth of 108 m at South Pole Station,which has an altitude of 2912 m and a mean annual temperature of -50.9 degrees C. Snow accumulation at South Pole was found to vary from 6.6 cm water/yr between 1760 and 1767 to a high of 7.8 cm water/yr between 1920 and 1930 (Giovinetto, 1960). The present accumulation rate is about 7.5 cm water/yr. The second core was drilled at Vostok Station, located at 77 degrees S, 108 degrees E, near the south geomagnetic pole. The mean annual temperature at Vostok is -55.6 degrees (NFAC, 1978), and the snow accumulation rate averages between 2.5 and 2.0 cm water/yr. In both cases, 1-m core sections were logged, bagged in polyethelene tubing, placed in aluminum-lined cardboard tubes, and shipped under refrigeration to Virginia Tech.