The 14C peak in AD 775 (M12) has been measured and confirmed globally in several studies since it was first measured in annual tree rings by Miyake et al. (2012). However, M12 data measurements in early- and latewood are limited. This paper presents the Δ14C values in early- and latewood from AD 762–776 Zelkova serrata tree rings from Bangu-dong, Ulsan, South Korea (35°33′N, 129°20′E). The results indicate no early rise in Δ14C values in the latewood of AD 774 in this sample located at mid-latitude. A comparison of the results of this and previous studies suggests latitude dependence (Büntgen et al. 2018); that is, the early rise of Δ14C in AD 774 was not observed at mid-latitudes in South Korea but was observed at high latitudes in Finland. The half-oxidation time of 14C was estimated from a detailed analysis of a small bomb peak in AD 1962. Based on the half-oxidation time, the Δ14C rise in the latewood, but not in the earlywood, of AD 774 in Finland, and the absence of a Δ14C rise in both the early- and latewood of AD 774 in South Korea, the 14C spike was estimated to have been produced from late April to mid-June in AD 774.

中文翻译：

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根据大气中 14C 的氧化时间和次年树木年轮中的 Δ14C 值估算公元 775 年 Δ14C 峰的出现时间

这14自从 Miyake 等人首次在年轮中测量到公元 775 年（M12）的 C 峰值以来，已经在多项研究中在全球范围内测量和证实了它。（2012）。然而，早期和晚期木材的 M12 数据测量是有限的。本文介绍了 Δ14公元 762-776 年早材和晚材的 C 值榉树韩国蔚山班古洞的年轮（35°33′N，129°20′E）。结果表明Δ没有提前上升14位于中纬度的样品中公元 774 年晚材的 C 值。本研究结果与以往研究结果的比较表明存在纬度依赖性（Büntgen et al. 2018）；即Δ的早升14公元 774 年的 C 在韩国的中纬度地区没有观测到，但在芬兰的高纬度地区观测到了。半氧化时间14C 是根据对公元 1962 年小炸弹峰的详细分析估算的。基于半氧化时间，Δ14芬兰公元 774 年晚材中 C 升高，但早材中没有升高，并且没有 Δ14C 在韩国公元 774 年的早材和晚材中均上升14据估计，C 尖峰是在公元 774 年的 4 月下旬至 6 月中旬产生的。