GNSS scintillation observations in the transition region between low and mid magnetic latitudes: On the response to solar flux variations

The occurrence of scintillation-causing ionospheric irregularities can be studied by monitoring Global Navigation Satellite System (GNSS) signals. A large number of investigations have already been carried out using GNSS-based scintillation measurements at low and high latitudes where ionospheric irregularities are known to occur frequently. For instance, amplitude scintillation, quantified by the S4 index, is associated with the occurrence of equatorial plasma bubbles (EPBs). EPBs develop at the magnetic equator and in the bottomside ionosphere and vertically extend along the magnetic field lines to low magnetic latitudes. A mid-latitudes, only a few cases of GNSS scintillation have been reported. This is, in great part, due to the lack of adequate instrumentation in this region. We still seek a better understanding about the occurrence rates, severity and drivers of mid-latitude scintillation.
Previously, we presented an overview of ionospheric scintillation and total electron content (TEC) measurements made by a low-cost monitor (ScintPi) deployed in Quebradillas, Puerto Rico (~25 deg. dip latitude) (Kikuchi et al., 2025). We focused on the spatio-temporal variation of scintillation observed during December Solstices on 2022, 2023 and 2024. We highlight that Puerto Rico can be described as located in a region that is transition between low and mid magnetic latitudes. Therefore, it allows us to study the latitudinal extent and impact of low-latitude ionospheric irregularities (e.g., EPBs).
In this poster, we will present a more comprehensive analyses than previously possible of the GNSS scintillation measurements made between December 2021 and December 2024 by the Quebradillas ScintPi. The routine measurements allowed us to investigate the day-to-day and inter-annual variation in quiet-time scintillation occurrence. The long-term set of measurements also enabled us to determine the response of the observed scintillation to changes in solar flux conditions.
Results to be presented and discussed include observed variations in the severity of scintillation with the increase of solar flux and the inter-annual variability in scintillation occurrence associated with EPBs. We will also present and discuss results related to the magnetic latitudinal extent of scintillation and how it responds to solar flux conditions.