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| INSTITUTET FÖR RYMDFYSIK | UPPSALA |
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| Swedish Institute of Space Physics | (59°50.272′N, 17°38.786′E) |
Master Project (45 c)/Masterprojekt (45 hp)
Investigating Ionospheric Scintillations Using Swarm and GNSS Measurements
Student: Bengu Biliroglu, Uppsala UniversitySupervisor: Stephan Buchert
Period: 2025
Abstract
Solar activity variations, including solar flares and coronal mass ejections, drive geomagnetic storms that inject energy into the magnetosphere–ionosphere system, producing field-aligned currents (FACs), auroral phenomena, and plasma density irregularities. These irregularities cause rapid fluctuations in Global Navigation Satellite System (GNSS) signal amplitude and phase, known as scintillations, which degrade navigation and communication accuracy. This study combines data from the ESA Swarm satellite mission—providing measurements of electron density and FACs—with ground-based GNSS scintillation receivers that record S4 (amplitude) and σϕ (phase) indices. Geomagnetically active days were selected using the Kp, Dst, and Hp30 indices. Results show that during major storms, FACs of up to 108 uA/m2 were observed near 67 degrees AACGM latitude, expanding equatorward at storm onset. The electron drift velocity in the ionosphere increased from about 600 m/s on quiet days to nearly 20,000 m/s under storm conditions. Ground stations recorded strong scintillations (S4 > 0.4, up to 1.4) at equatorial latitudes, coinciding with Swarm detections of plasma bubbles. Correlation analysis revealed a link between electron density irregularities and scintillation intensity (Pearson r > 0.7 for Swarm A and C). Overall, the findings confirm that space weather–driven ionospheric disturbances impact GNSS signal stability, particularly during geomagnetic storms at high and equatorial latitudes. These results highlight the importance of integrating satellite and ground-based observations to improve space weather monitoring and the reliability of global navigation systems.Results
Final report
![[Swarm]](../../img/swarm.jpg)
The Swarm satellites, each carrying two IRF Uppsala Langmuir probes providing the in situ plasma density measurements used in this work.