C03_05

Toward detections of ¹⁴C spikes: regional differences in ¹⁴C data

Miyake F¹, Hakozaki M², Kimura K³, Tokanai F⁴, Nakamura T¹, Takeyama M⁴, Moriya T⁴, Panyushkina I⁵, Hantemirov R⁶, Helama S⁷, Jull A⁵

¹Nagoya University, Nagoya, Japan, ²National Museum of Japanese History, Sakura, Japan, ³Fukushima University, Fukushima, Japan, ⁴Yamagata University, Yamagata, Japan, ⁵University of Arizona, Tucson, USA, ⁶Institute of Plant and Animal Ecology, Ekaterinburg, Russia, ⁷Natural Resources Institute Finland, Rovaniemi, Finland

Annual ¹⁴C data in tree rings is a good proxy for past extreme solar energetic particle (SEP) events. As far, several signatures of extreme SEP events have been found in ¹⁴C data, such as 774 CE, 993 CE, 660 BCE, and 5259 BCE events. Although these events are characterized by a rapid ¹⁴C increase and a following decrease, ¹⁴C data recorded worldwide do not always show similar variations. Such regional differences in ¹⁴C data hinder a consistent understanding of the event and a detection of small 14C spikes, and affect a dating using ¹⁴C spikes. Here, we focus on a timing of rapid ¹⁴C increases and discuss a possible relationship with the atmospheric transport effect.