We study plasma density variations within the ionosphere and their effects on trans-ionospheric signals, with a geodetic focus on Sweden from 2014 to 2023. We look for temporal, spatial, seasonal, and solar cycle patterns. We also discuss the percentage of occurrence of ionospheric irregularities and GNSS signal disturbances within the data at hand. We use in situ data collected by ESA-Swarm satellites and ground data provided by the Lantmäteriet-Swepos network ionosphere monitor. We find that high-latitude regions are susceptible to displaying more irregular electron density fluctuations (i.g., polar cap patches) than mid-latitudes. We also find that GNSS signal interference resulting in increased receivers’ positioning uncertainty is predominant at high latitudes. On the other hand, increased positioning uncertainty may be detected at noon in mid-latitude regions, mainly due to solar radiation exposure. Furthermore, hourly geomagnetic effects at high latitudes induce enhanced electron density fluctuations and positioning uncertainty at night. Findings also show more electron density fluctuations around winter and less in summer. Moreover, we find that the solar cycle influences the intensity of electron density fluctuations and positioning uncertainty, with the seasonal effects being more pronounced during periods of increased solar activity. Finally, results show that when ionospheric irregularities are observed, disturbances in GNSS signals may be detected, leading to imprecision in positioning services. Furthermore, we see that the absence of ionospheric irregularities results in a generally safe path for GNSS signals, which is beneficial for positioning accuracy. This comprehensive research enhances our understanding of ionospheric behavior in higher latitude environments and its impact on GNSS signals. Future research in this field could go deeper into the specific mechanisms driving electron density fluctuations and scintillation effects, explore additional geographic regions, and consider longer periods to refine our understanding of ionospheric dynamics and its implications for advanced space weather forecasting and satellite system resilience.
| Identifer | oai:union.ndltd.org:UPSALLA1/oai:DiVA.org:uu-531855 |
| Date | January 2024 |
| Creators | Cherry, Arthur |
| Publisher | Uppsala universitet, Institutionen för fysik och astronomi, Uppsala universitet, Institutet för rymdfysik, Uppsalaavdelningen |
| Source Sets | DiVA Archive at Upsalla University |
| Language | English |
| Detected Language | English |
| Type | Student thesis, info:eu-repo/semantics/bachelorThesis, text |
| Format | application/pdf |
| Rights | info:eu-repo/semantics/openAccess |
| Relation | FYSAST ; FYSMAS1233 |
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