Global Citizen-Science Observations of Fragmented Aurora-Like Emissions

Abstract. Fragmented aurora-like emissions (fragments) are small-scale green E-region structures that have previously been reported mainly from high-latitude locations near the poleward auroral oval boundary. Here we present a global citizen-science dataset of 26 fragment observations from 2017 to 2025, collected through an international citizen-science campaign via the Skywarden platform. The observations span magnetic latitudes from approximately 53 to 76°, a wide range of magnetic local times and activity levels, both hemispheres, and diverse auroral conditions. The dataset substantially extends the observational record of fragments beyond previously reported high-latitude regions. Both isolated fragments (type I) and the quasi-periodic wave-like fragments (type II) are represented in this broader geographical context.

To assess fragment locations relative to the auroral oval, three case studies combining satellite observations with ground-based auroral images were analysed in detail. These demonstrate that fragments occur poleward of the oval in Antarctica, equatorward of the oval in Manitoba, and within the oval near the diffuse-discrete boundary in Iceland. Together, the global dataset and case studies show that fragments occur across a much broader range of auroral and geomagnetic conditions and oval positions than previously documented. The results demonstrate the scientific value of citizen-science observations for studying short-lived and localised auroral phenomena.