Figure 2: Measured concentrations of nitrate in several polar ice cores around 775 AD (see Table S1).
From: Atmospheric impacts of the strongest known solar particle storm of 775 AD
Panel A: Law Dome, data with about monthly resolution; dating uncertainty is ±7 year. Panel B: Talos Dome, data with quarterly resolution. Panel C: Annual data from EPICA Dome C. Panel D: data from GISP2. Dating uncertainty of these three data sets can be also on the order of a several years. Panel E: NEEM, data with about 20 samples per year time resolution; note that the NO3 data is from the NEEM main core, while the 10Be peak at 774–775 was derived on a shallow core close-by (NEEM-S1). The relative dating uncertainty of these two neighboring cores should not be more than a few years and clearly smaller than 7 years. Within this uncertainty no NO3 peak is found in the NEEM main core. The vertical red dashed line depicts the proposed year of the SEP event.
