Speaker
Description
Extreme solar particle events (ESPEs) are caused by rare, enormously intense solar eruptions and can produce globally detectable spikes in tree-ring radiocarbon ($^{14}$C), known as Miyake events, which serve as precise chronological tie-points and indicators of extreme solar activity. After production, radiocarbon is subjected to the complex carbon cycle, including large- scale atmospheric transport, which is crucially important for fast and strong Miyake events with highly inhomogeneous 14C production. In this study, we apply the 3D dynamical climate-chemistry model SOCOL:14C-Ex, which simulates atmospheric $^{14}$C production and transport with high temporal and spatial resolution, to quantify extreme solar particle events. Response curves of Δ$^{14}$C to a reference ESPE (100 × GLE #69) were computed for different event dates in both hemispheres and used to analyse Miyake events under varying background conditions. Seven strong events over the past 14 millennia (AD 993, AD 774, 664 BC, 5260 BC, 5411 BC, 7177 BC, and 12351 BC) were analysed by fitting the reference curves to the available annual 14C data, identifying the most probable values and confidence intervals of their strength (relative to the reference ESPE) and timing. By applying corrections for the geomagnetic and atmospheric (CO$_2$) factors, the strengths of the corresponding ESPEs were reassessed.