Global and regional modelling of the core field and its variations

The internal and external Gauss coefficients model the magnetic field generated within and outside the Earth, respectively. The core field coefficients change over time as the core-generated magnetic field evolves. To describe this variation, spherical harmonic analysis is commonly used. I have been involved in developing the International Geomagnetic Reference Field (IGRF), as well as in refining more precise internal models to better describe both the main field and the crustal component.

Improving Earth’s magnetic field models—by providing a more accurate description of both internal and external sources—is an ongoing effort within the scientific community. This is reflected in the continuous production of updated models such as CHAOS and GRIMM, in which I have contributed at various stages.

By utilizing data from the MAGSAT, CHAMP and Swarm satellites, we have been able to identify and interpret main field variations over the past decades, uncovering features at previously inaccessible length scales. At the core surface, changes in the core field are weak beneath the Pacific Ocean, while they are stronger at the polar latitudes and in regions centered around South Africa.

To overcome the limitations of classical methods and better capture the global and regional patterns of the magnetic field, new modeling techniques are being developed. One such method, which I have worked on, involves wavelet analysis. This approach plays a key role in addressing the complexities of Earth's magnetic field.

Geomagnetic jerks

The rate of change of the Earth's declination, for example, shows several abrupt shifts in the general trend of secular variation. The most notable of these changes, determined by using magnetic observatory data, occurred around 1925, 1969, 1978, 1992, and 1999.More events have been observed during the 21st century, when satellite magnetic data are available. These sudden changes are known as geomagnetic jerks or impulses. Despite being well documented, the causes of geomagnetic jerks remain poorly understood and, at present, are unpredictable.

A significant portion of my research focuses on the detection, analysis, and interpretation of these events using data from magnetic observatories and satellite measurements.

Lithospheric magnetic field

The magnetic field arising from magnetic materials in the Earth's crust is highly variable across spatial scales and is commonly referred to as the anomaly field. Understanding the crustal magnetic field is essential for geophysical exploration, as it can help identify local geological structures.

Recent models have been developed to improve the characterization of the crustal magnetic field and highlight well-known magnetic anomalies. One of the major initiatives I have participated in is the World Digital Magnetic Anomaly Map (WDMAM), which provides the scientific community with a global 5 km resolution magnetic anomaly grid. This map is instrumental in modeling and interpreting not only shallow geological features but also larger tectonic provinces. I have actively contributed to this project, from collecting magnetic data to developing analytical methods.

External field, its variations and the space weather

In addition to regular daily variations, the Earth's magnetic field also experiences irregular disturbances, the most significant of which are magnetic storms. The prevailing conditions in the solar-terrestrial environment, which influence these disturbances, have also been a focus of my research. I have shown that in modeling strongly heterogeneous fields—such as those generated by external currents—wavelet techniques can offer valuable insights. Wavelets allow for a more geometric description of these fields, helping to capture the complexity of space weather phenomena and their effects on Earth's magnetic environment.