Small radiocarbon rise, 1261 to 1262 (Miyahara 2022)

Miyahara 2022, asunaro tree from northern Japan, high precision: 1260 -13.74, 1261 -14.34, 1262 -12.09, 1263 -12.82, 1264 -16.23 permil (errors about 0.5). A rise of 2.2 permil into 1262, about 3 sigma, the smallest radiocarbon solar storm candidate yet claimed; about 13 percent of the 774 event. The authors say a disagreement with Brehm's data needs more measurements. Brehm's Swiss tree shows no rise. Timing rule from Miyahara et al. 2022: their asunaro (a Japanese conifer) photosynthesises from April and builds each ring mainly from April to August carbon of the same year. So a jump between ring N and ring N+1 means the burst of carbon-14 arrived after about August of year N and before about mid-year N+1. Oaks, by contrast, build their spring wood from the previous year's stored sugar, so oak records can lag a year.