Studies of traveling ionospheric disturbances using rapid-run ionosonde, EISCAT radar and GPS TEC
Thesis event information
Date and time of the thesis defence
Place of the thesis defence
Auditorium L10, Linnanmaa campus
Topic of the dissertation
Studies of traveling ionospheric disturbances using rapid-run ionosonde, EISCAT radar and GPS TEC
Doctoral candidate
Master of Science Samson Tilahun Moges
Faculty and unit
University of Oulu Graduate School, Faculty of Science, Sodankylä Geophysical Observatory
Subject of study
Physics
Opponent
Doctor of Philosophy Jaroslav Chum, Institute of Atmospheric Physics (IAP) of the Czech Academy of Sciences (CAS)
Custos
Professor Eija Tanskanen, University of Oulu
Statistical studies of traveling ionospheric disturbances at high latitudes and its storm-time observation at low latitudes
Traveling Ionospheric Disturbances (TIDs) are wave-like variations in ionospheric plasma density that can disrupt radio communication and satellite-based navigation. Their impact on positioning accuracy is particularly critical for autonomous vehicles, making TIDs a timely research topic. At high latitudes, TIDs are generated by several mechanisms, including Joule heating, particle precipitation, and lower atmospheric forcing.
This doctoral thesis investigates the temporal variability of TID occurrence, their dependence on solar activity, and their vertical propagation characteristics at high latitudes. It also examines their role in low-latitude ionospheric irregularities during periods of intense geomagnetic activity. The work consists of five articles:
The first article addresses large-scale TIDs (LSTIDs) associated with the intense geomagnetic storm of March 17, 2015, in the East African sector and their impact on the equatorial ionospheric irregularity pattern.
The second article introduces a deep-learning method for the automatic extraction of ionospheric parameters from Sodankylä ionosonde data.
The third article analyzes TID occurrence across seasons using the critical frequency data.
The fourth article investigates the dependence of TID amplitudes on solar activity.
The fifth article examines seasonal and altitude variations of TIDs using EISCAT very high frequency radar measurements over Tromsø.
The results show that TID occurrence and characteristics vary significantly with season, solar activity, and background atmospheric conditions.
This doctoral thesis investigates the temporal variability of TID occurrence, their dependence on solar activity, and their vertical propagation characteristics at high latitudes. It also examines their role in low-latitude ionospheric irregularities during periods of intense geomagnetic activity. The work consists of five articles:
The first article addresses large-scale TIDs (LSTIDs) associated with the intense geomagnetic storm of March 17, 2015, in the East African sector and their impact on the equatorial ionospheric irregularity pattern.
The second article introduces a deep-learning method for the automatic extraction of ionospheric parameters from Sodankylä ionosonde data.
The third article analyzes TID occurrence across seasons using the critical frequency data.
The fourth article investigates the dependence of TID amplitudes on solar activity.
The fifth article examines seasonal and altitude variations of TIDs using EISCAT very high frequency radar measurements over Tromsø.
The results show that TID occurrence and characteristics vary significantly with season, solar activity, and background atmospheric conditions.
Created 26.2.2026 | Updated 27.2.2026