Automatic Identification of Past Radiation Belts Electron Enhancement Events Using a Ground-Based Parameter

We propose a new method for automatically identifying radiation belt electron enhancement events using Ca, a ground-based 1D surrogate index for the global dynamics of the electron radiation belts. Our method improves event identification by accurately determining start and end dates, considering intensification and return-to-equilibrium phases, and resolving ambiguity between single, longer-lasting events and multiple, successive events. The events detected after 1995, are automatically associated with possible physical driving causes, such as interplanetary coronal mass ejections and stream interaction regions. The resulting list of events is consistent with our understanding of how radiation belts respond to interplanetary drivers, in terms of event intensity, duration, and distribution over the solar cycle. The list of events from 1868 to 2021 is publicly available for statistical analyses of radiation belt climatology, constructing space weather forecasting models, and selecting periods of interest for studying physical processes.