The Spanish contribution to IGRF-14

Abstract This study presents the methodology and results of the Spanish team contribution to the 14th generation of the International Geomagnetic Reference Field (IGRF-14), headed by Universidad Complutense de Madrid (UCM). The IGRF-14 requires three model products: the Definitive Geomagnetic Reference Model for epoch 2020.0 (DGRF2020), the main field description for epoch 2025.0 (IGRF2025), and a predictive secular variation (SV) model from 2025.0 to 2030.0 (SV2025-30). Using data from the global network of ground-based geomagnetic observatories and the European Space Agency’s Swarm satellite mission, we developed two 1-year parent models covering the periods from July 2019 to July 2020 and from September 2023 to September 2024 to derive candidates for the three required products. These models account for the Earth’s outer core, lithospheric, external magnetospheric, and magnetospheric induced fields. A bootstrap approach was employed to generate an ensemble of sub-models, providing both coefficient values and uncertainty estimates. These uncertainties were further analysed by studying the resulting covariance matrices. The results show good fits to both observatory and satellite data, with significant improvements compared to the previous IGRF-13 Spanish candidate. In addition, we provide a test validation against independent data from the Macau Science Satellite-1 (MSS-1) that further supports the robustness of our models. Graphical Abstract