Nitrate concentrations and electrical conductivity in an ice core from central Greenland have been measured simultaneously on 1.5 cm sections along the entire length of the 122 m core. This method of micro-resolution (time resolution is 1 week --1 month) provides for statistically significant determinations of rapid variations in nitrate fallout from the polar stratosphere superimposed on a background from all other sources. The seasonal No-3 background variations and the volcanic signal contained in the electrical conductivity data provide accurate dating of the ice core. This type of micro-resolution nitrate measurement appears to be useful as a tool to investigate the possible sources of polar nitrate anomalies such as solar proton events. ¿ American Geophysical Union 1995.