Mesoscale Ionospheric Irregularity Oval at High Latitudes Observed by Global GNSS Networks (2010–2024)

This study investigates high-latitude ionospheric mesoscale irregularities associated with energetic particle precipitation and magnetosphere-ionosphere-thermosphere coupling processes within the auroral oval using ground-based Global Navigation Satellite Systems (GNSS) total electron content (TEC) measurements. This scale size is much larger than those associated with GNSS scintillations, which range from sub-kilometers (small scales) to > 10 km (large scales). Analyzing 15 yr of data from 2010 to 2024, we characterize, for the first time, the climatology of enhanced intensity of ionospheric mesoscale irregularities at high latitudes. The observed intensity of irregularities in GNSS TEC fluctuations can serve as a proxy for the dynamic behavior of the auroral oval which varies with magnetic local time, longitude, latitude, season, solar activity cycle, geomagnetic disturbances, and hemisphere. The spatial distribution of the irregularity is oval-shaped and therefore this pattern is named as “irregularity oval”; the morphology of the irregularity oval is generally aligned well with the known variations of auroral oval established by using other technologies. While the primary goal has been to document systematically these irregularity long-term observations, future work will focus on the development of a novel GNSS TEC-based “irregularity oval” model.