Testing the hypothesis of planetary waves in Earth´s core

Planetary waves, similar to those that control weather on Earth, are thought to exist in Earth’s core.

These waves, which form in response to the rotation of the planet and the presence of a magnetic field, carry important information about dynamical processes in the core.

In theory, it is possible to detect planetary waves by studying the associated westward motions of Earth’s magnetic field.

Westward drift of the field has been observed over the past 400-years, but it is currently not clear whether this is due to wave propagation or bulk core fluid motions (advection). There is a crucial need for longer and higher-resolution timeseries data.

Here we propose to use a novel geomagnetic field modelling approach, combined with new palaeomagnetic data from strategic locations, to reconstruct millennial-scale field variations with unprecedented resolution. We will use methods, designed to study planetary waves in meteorology, to identify signatures of planetary waves.

In addition, we will develop new methods to extract core flow information to test the hypothesis that the observed westward drift is due to advection rather than wave propagation.

Core flows are expected to affect Earth’s rotation rate and can be verified using independent millennial-scale reconstructions of length-of-day.

Ultimately, the results from this research will help constrain the energy budget of the geodynamo with important implications for our understanding of the thermal evolution of our planet.