Arctic Six Fellow thesis defence: From strong to superstorms

University of Oulu's Arctic Six fellow Otto Kärhä has his thesis defense on the 28th of November: "From strong to superstorms: regional effects and spatial geomagnetic gradients driven by extreme space weather"

Doctoral researcher, Master of Science (Technology) Otto Kärhä, will defend his doctoral thesis on the 28th of November at 12:00.

Kärhä was appointed as a Arctic Six Fellow in 2022.

Kärhä will defend his doctoral dissertation at the University of Oulu titled “From Strong to Superstorms: Regional Effects and Spatial Geomagnetic Gradients Driven by Extreme Space Weather.” The research focuses on how geomagnetic storms, triggered by solar eruptions, cause large-scale disturbances in Earth’s magnetic field, posing risks to power grids and communication systems.

The study examined regional variability in magnetic disturbances by comparing data from magnetometer stations, particularly in the auroral zone. Results revealed significant differences in storm-time magnetic field variations: over 500 nanoteslas across 170 km during a 1977 storm and about 1,200 nanoteslas across 160 km during the 2003 Halloween superstorm. The strongest variations occurred on Earth’s nightside during peak storm phases.

Full event page can be found here: https://www.oulu.fi/en/theses/strong-superstorms-regional-effects-and-spatial-geomagnetic-gradients-driven-extreme-space-weather

Created 17.11.2025 | Updated 17.11.2025