The geomagnetic secular variation is now one of the best documented part of the main geomagnetic field record. Yearly to decadal variations of the field at the core-mantle boundary are now described with an unprecedented level of temporal and spatial accuracy, thanks to the joint use of satellite and ground-based data. They are key to understanding the physical mechanisms within the core that govern these changes: advection by the fluid flow, hydromagnetic waves, a combination of these two, with possibly an ounce of diffusion.

This session aims at bringing together people from the data and modelling community, and welcomes contributions addressing the determination of time-dependent models of the Earth's magnetic field at the core-mantle boundary, their interpretation in terms of the core state, as well as physical models of the geomagnetic secular variation and attempts to explain its different components.