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Geomagnetically induced currents (GIC), ultimately due to disturbed conditions in the Earth’s space environment caused by Space Weather, affect power transmission grid transformers differently depending on latitude, ground conductivity, transformer type and grid topology. We evaluate the risk from GIC threat to transformers as a product of hazard and vulnerability. Hazard evaluates the probability of occurrence of geoelectric fields, which in turn depends on the primary currents flowing above the site in question, as well as on the local subsurface conductivity. On the other hand, the vulnerability of transformers depends on their winding resistances and on the network topology, which will favor GIC flow for certain orientations of the regional geoelectric field. Given that the period of available data is finite, and that it is precisely the large GICs that cause the most damage, an adequate risk assessment requires extreme value analysis techniques to obtain a continuous and reliable probability function for extreme GIC events. The method is exemplified with the case of one of the most vulnerable transformers of the Spanish power grid using magnetic observatory records of the period 2000 – 2021 and a ground conductivity model for the Iberian Peninsula., The 28th IUGG General Assembly (IUGG2023) (Berlin 2023)

Critical infrastructures on which society depends are affected by what are known as geomagnetically induced currents. As a consequence of Faraday's law of induction, which is associated with time variations of the magnetic field, an electromotive force is induced in the conductive earth. The (geo)electric field generated in this way acts as a voltage source through the power transmission networks, so that the induced currents during large geomagnetic storms can damage the transformers where the circuit is grounded. Many countries, such as Spain, have undertaken studies aimed at assessing the vulnerability of their power grids to the danger posed by this phenomenon, but one question that remained open was whether the grids that transmit power across their islands deserve attention. We have constructed models for the grids in each of the individual systems and used resistivity models of the lithosphere for each group of islands, from which we have calculated the surface impedances. The respective models of electrical admittances of the grids have been combined with the geoelectric field derived from the convolution of the recorded (or expected in an extreme scenario) geomagnetic storms and the impedances calculated from the geoelectrical models to derive the expected GICs in the power lines, substations, and transformers. The results of our study show that the vulnerability of the Canary Islands is very low, while that of the Balearic Islands is not negligible., The 28th IUGG General Assembly (IUGG2023) (Berlin 2023)

Additional file 2. Maps of the Y secular acceleration changes (δSA) from August 2015 to June 2020 at the Earth’s surface obtained from the CHAOS-7.7 model.

Additional file 1. The 2020-jerk in geomagnetic observatory and Swarm data. Figure S1. Monthly means of the East geomagnetic component Y (yellow dots) and the estimations from CHAOS-7.7 model at the same locations (red and blue lines). For an appropriate comparison, the average Y values for the whole time interval have been removed (see text for details). Note that after August 2020 the estimations from CHAOS-7.7 (blue lines) are likely caused by the model regularization instead of the data (see “Discussion: a global view from geomagnetic models” Section of the main text for more details). Figure S2. Double linear fit of the Y-component SV at geomagnetic observatories leading to the values of Table 1 (see main text). a and b refer to the 2017-jerk, while c through g correspond to the 2020-jerk. Figure S3. Yellow dots: SV of the East component Y from Swarm-A data relocated at 440 km altitude over the indicated observatory locations (see main text for details). Red and blue curves: SV estimation from CHAOS-7.7 model. Note that after August 2020 the changes in the curves (blue lines) from CHAOS-7.7 are likely caused by the model regularization instead of the data (see “Discussion: a global view from geomagnetic models” Section of the main text for more details). Figure S4. SA power for each harmonic coefficient from the CHAOS-7.7 model until degree n = 8 at the CMB. Vertical blue bands indicate the epochs of the reported jerks. Note that after mid-2020 the SA power curves from CHAOS-7.7 are biased by the model parametrization instead of the geomagnetic data providing unreliable values (see “Discussion: a global view from geomagnetic models” Section of the main text for more details).

Additional file 3. Maps of the secular acceleration (SA) of the radial field at the CMB from July 2015 to June 2020 obtained from the CHAOS-7.7 model.

22 pages, 9 figures

Additional file 6: Figure S5. RMS errors of vector and scalar observatory data versus time (modified Julian days relative to CASE* = 2015.0 for the DGRF parent model—blue lines and to CASE* = 2019.16 for the IGRF parent model—red lines).

Additional file 8: Figure S6. (Left column) Maps of external field vector components for the DGRF and IGRF parent models at 2015.0 and 2019.16, respectively. (Central column) Maps of external field vector components given by the CHAOS-6 model at 2015.0 and 2019.16, respectively. (Right column) Residual maps of the difference between the previous maps.

Additional file 3: Figure S2. Number of Swarm data for each sub-dataset of 8000 Swarm data (see text for details) considering temporal bins of 5 days (a and c) and 30 days (b and d). Upper panel: data for the DGRF parent model. Lower panel: data for the IGRF parent model. Each column contains the mean ± standard deviation of the number of data within the temporal bin calculated from the 1000 sub-datasets of 8000 Swarm data each.

Additional file 2: Figure S1. Number of Swarm data within each of the 1000 considered spherical caps for the a) Swarm A, b) Swarm B and c) Swarm C satellites for the (upper panel) DGRF and (lower panel) IGRF parent models.

Additional file 7: Table S2. List of Gauss coefficients for the IGRF-13 candidate products. Columns 1 and 2 are the harmonic degree n and order m, respectively. For each candidate (i.e., DGRF, IGRF, and VS) the following columns provide the Gauss coefficients $$g_{n}^{m}$$ g n m and $$h_{n}^{m}$$ h n m and their uncertainties (denoted by $$\Delta g_{n}^{m} , \Delta h_{n}^{m}$$ Δ g n m , Δ h n m ) obtained from the normal distribution (1-σ of confidence level) of each coefficient. The dots in $$\dot{g}_{n}^{m}$$ g ˙ n m and $$\dot{h}_{n}^{m}$$ h ˙ n m of the last 4 columns represent the first time derivative, i.e., the secular variation.

Additional file 1: Table S1. List of observatories used in the DGRF and IGRF parent models. First column is the associated number used in Fig. 2 of the main text, second column is the IAGA code, and third column is the spatial weight used in the modelling approach.

Assuming optimal conditions, the δDδI vector magnetometer can be considered as a semi-absolute instrument. In this paper, the real situation and its differences with the ideal one are critically examined and regarded as potential sources of error. The analysis is applied to the equipment designed by the British Geological Survey (BGS) in the late 1980s, and the given figures are provided from the instrument in use at the Livingston Island Geomagnetic Observatory (LIV). Improved versions have been developed since then, being based on generally the same principles of measurement; thus, most of the results shown can be adapted to the new generation of magnetometers of this type.

Intercomparison of momentary values from observatories across Europe has been used as a test of reliability for the magnetic stations of this area, as well as for the whole net. One of the techniques used, based on the standard deviation of the mutual differences of monthly mean values, has permitted to obtain a measure of quality of the Ebre Observatory (EBR) magnetic elements for the period 1997-2001. The results nearly coincide with those obtained for the most significant observatories of the network, pointing out a good performance of EBR observatory.

Poster presentado en: International Workshop "Challenges for Geomagnetism Aeronomy and Seismology in the XXI Century: on the occasion of the Centennial Of Ebro Observatory". Roquetes (Tarragona), España. 29 september - 10 October 2004., Since 1996 Ebre Observatory is monitoring and studying the geomagnetic field not only in Spain but also in Antarctica. In this poster, a brief introdution to LIV Observatory characteristics and instruments is given, together with some experimental results and related models, obtained from the analysis of its data. Regional and continental magnetic studies have also been developed to compile and analyze marine and aeromagnetic anomaly data in the South Shetland Islands -Bransfield Strait- Antarctic Peninsula region, and to produce a main field plus secular variation geomagnetic reference model valid from 1960 onwards.

Resumen tomado de la revista. Resumen en Inglés. Monográfico: Deontología y práctica profesional Constituye un gran error olvidar que los profesionales del derecho no pueden ser simples aplicadores de códigos normativos, sino que a partir de una serie de declaraciones de principios deben ser intérpretes de la ley, siempre en clave constitucionalista. Nadie es aséptico por naturaleza ante un conflicto social. No interesa que el poder judicial sea débil, vulnerable e ineficaz, para así criticarlo cada vez que se discrepe de sus decisiones. Al poder político le gustan mucho más los juristas que se limitan a aplicar de forma literal y neutra la ley. El objetivo primordial del derecho es decidir lo que es justo. La administración de justicia tiene que ser honesta, servida por personas con una sólida formación jurídica; pero, al mismo tiempo, dotadas también de una inseparable formación complementaria en campos tan próximos al derecho como son la ética, la criminología, la educación psicosocial. El lenguaje jurídico debe ser también vehículo de comprensión de la ley. Cataluña ESP