Secular shift of the magnetic dip pole and its consequences for auroral boundaries (PoleMotion)

This is chapter 1 of the State of Environmental Science in Svalbard (SESS) report 2024 (https://sios-svalbard.org/SESS_Issue7).

The Earth’s northern magnetic dip pole has shifted approximately 1500 km over the past 30 years, moving several tens of kilometres annually due to changes in the flow of metal alloys within Earth’s interior. The geomagnetic field influences the aurora’s location, leading to questions about whether it shifts with the magnetic pole. This work investigates long-term geomagnetic field variations and their impact on the auroral oval, as observed in Svalbard. Observations of the magnetic field at Hornsund, Svalbard, reveal a magnetic field rotation consistent with the dip pole motion.

Using satellite remote sensing, we show that the aurora over Svalbard is slowly but consistently moving equatorward. Observations using the EISCAT Svalbard radar seem to confirm this motion, though more investigations are needed before definitive conclusions can be drawn from EISCAT.

Variations in the local magnetic field have significant societal implications, particularly for navigation and infrastructure in Svalbard. The magnetic field remains crucial for navigation, and any changes in magnetic field direction imply that maps and navigation aids need to be updated. For example, runway designations and approach procedures at airports are based on magnetic orientation. These must be revised as the magnetic field changes. At Longyearbyen airport, runway designations were recently changed due to changes in the geomagnetic field.