Climatology of GPS ionospheric scintillation over North European high and mid-latitudes under different solar activity conditions

Abstract

Under perturbed conditions caused by intense solar wind-magnetosphere coupling, the ionosphere may become highly turbulent and irregularities, typically enhancements or depletions of the electron density embedded in the ambient ionosphere, can form causing diffraction effects on the satellites signals passing through them. Such effects can cause GPS navigation errors and outages, abruptly jeopardizing its performance. Due to the morphology of the geomagnetic field, whose lines are almost vertical at high latitude, polar areas are characterized by the presence of significant ionospheric irregularities. The understanding and consequent mitigation of the effect of the scintillation phenomena is important, not only in preparation for the next solar cycle, whose maximum is expected in 2013, but also for a deeper comprehension of the dynamics of the high-latitude ionosphere. We analyze data of ionospheric scintillation over North European regions under different geomagnetic condition, to characterize the GPS scintillation phenomena under different forcing conditions of the near-Earth environment and to develop a “scintillation climatology” of the high and mid latitude ionosphere. The scintillation occurrence as a function of the magnetic local time and of the altitude adjusted corrected magnetic latitude is analysed, together with the Total Electron Content (TEC) information, to put in evidence the link between electron density gradients and ionospheric irregularities causing scintillation. The results shown herein are obtained merging observations from a network of GISTMs (GPS Ionospheric Scintillation and TEC Monitor) located over a wide range of latitudes in the Northern hemisphere. Findings confirm the associations of the occurrence of the ionospheric irregularities with the position of the auroral oval and of the ionospheric trough walls and show the contribution of the polar cap patches even under solar minimum conditions. This work could contribute to the development of forecasting tools for GPS ionospheric scintillation prediction.