Fig. 3
From: Solar superstorm of AD 774 recorded subannually by Arctic tree rings
Latitude vs. the 14C intensity I14C. The red line is a linear fit to the data. The uncertainties are based on error propagation and represent one standard error, and the dashed lines indicate the 95% confident intervals for the fit. The 14C intensities are obtained by fitting a GDF with each data set and by defining the I14C as an integral of this curve (see Methods). NH1 zone has been adopted from Hua et al.18. Differences in the 14C spatial distribution are manifested by distinct zones that span through both hemispheres, latitudes North of 40°N (NH1 zone) having the highest bomb-peak 14C intensities
