Ice-core evidence for a small solar-source at atmospheric nitrate

A precision-dated ice-core nitrate record from Law Dome, coastal East Antar ctica is compared to the timing of known solar proton events and geomagneti c storms over the period 1888 to 1995. We find statistical evidence for a s ignificant (P < 0.03) but small elevation in mean nitrate concentrations fo llowing the solar events (<similar to> 11% over the 12 months beginning 3 m onths post-event). While some solar events are identifiable in the nitrate record, most are not distinguishable from the background noisy signal (whic h has numerous large peaks), and some solar events show no nitrate elevatio n above even mean levels.