Scottish Alliance for Geoscience, Environment and Society

Frederik Dahl Madsen

Research interests:

My main research interest is geomagnetism. I am particularly interested in inverting geomagnetic data for core-surface flow, in an attempt to understand the dynamics that happen on the core-surface, to better comprehend the dynamics in the core. A lot of international research come at this problem through numerical simulations or data assimilation, but I am primarily interested in approaching it from the data-side.

I am also interested in studying intra-decadal variations in the length-of-day. This is affected by many systems – angular momentum transfer from the atmosphere and oceans, and tidal effects from the moon – but after these effects are accounted for, there is a strong periodic signal from the solid Earth, that we attribute to the core. Understanding the periods in this signal can help us understand things like waves propagating through the core, core-nutation, and other phenomena.

Career history:

I completed my integrated masters in Geophysics at the University of Edinburgh in June 2022. During my bachelors, I worked on forecasting space weather, particularly the effect of extreme space weather at ground level. I presented this work at the IAGA-IASPEI 2021 scientific meeting, the 2021 European Space Weather Week, and published it in Frontiers in Physics in the summer of 2022.

I took a turn in my masters year, and started looking at the internal geomagnetic field rather than the external. Here, I learned how to create core-surface flow models from inverting satellite data, in order to investigate the behaviour of the geomagnetic field. In parallel, with this, I was working Dynamic Earth to create learning resources on space weather and aurora for primary schools. This is now available on the Dynamic Earth website, and we created a guide for Scottish citizens on how to observe aurora (even if you live in the central belt!).

I am using my skills in core-surface flow in my PhD, still at the University of Edinburgh, which I started in the summer of 2022. Now I am looking at geomagnetic jerks – localised abrupt changes in the magnetic field. These are currently poorly understood, but often occur simultaneously with changes in the length-of-day. Despite being in my first year, I have already presented work at the European Geoscience Union’s general assembly 2023, and will be presenting new work at the IUGG general assembly in July 2023.

Active research projects:

Currently I am involved in one research project, which is my PhD titled: "Reconciling geomagnetic jerks with intradecadal variations in length-of-day"

Recent publications:

Madsen, F. D., Whaler, K. A., Hammer, M. D., Holme, R., Brown, W., Beggan, C. (2023). Investigating geomagnetic jerks with Swarm: Using the spatial gradient tensor for flow modelling. Copernicus Meetings (EGU)

Madsen, F. D., Beggan, C. Whaler, K. A. (2022). Forecasting changes of the magnetic field in the United Kingdom from L1 Lagrange solar wind measurements. Frontiers in Physics.

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