Special issue “International Geomagnetic Reference Field: the thirteenth generation”

The large-scale time-varying portion of Earth’s internal magnetic field originates from a dynamo process inside the outer core. This geodynamo drives changes in Earth’s magnetic field on timescales ranging from less than 1 year to hundreds of millions of years. Monitoring the large-scale internal geomagnetic field and its temporal variations is fundamental to improving our understanding of our planet’s interior dynamics, as well as maintaining and developing technology designed to utilize magnetic field observations for the benefit of society.