Geomagnetic field excursions: revealing the extreme states of Earth's outer core

Descripción del proyecto

Resolver los misterios de las excursiones geomagnéticas

El campo magnético de la Tierra es fundamental para proteger nuestro planeta de las radiaciones solares y cósmicas nocivas. Sin embargo, las excursiones geomagnéticas (episodios de baja intensidad del campo magnético) perturban esta barrera protectora. Dichos fenómenos, que implican direcciones magnéticas anómalas sin inversiones completas de polaridad, pueden tener importantes consecuencias tecnológicas, medioambientales y climáticas. A pesar de su importancia, nuestra comprensión de las excursiones geomagnéticas sigue siendo limitada. En este contexto, el proyecto EXCURSION, financiado por el Consejo Europeo de Investigación, pretende colmar esta laguna construyendo el primer modelo basado en datos del campo geomagnético durante el período Cron Brunhes (los últimos 780 000 años). Al integrar reconstrucciones de alta resolución de las excursiones con simulaciones avanzadas de dinamos tridimensionales y novedosas técnicas de aprendizaje automático, el proyecto mejorará las predicciones de futuros fenómenos geomagnéticos.

Objetivo

EXCURSION resolves around fundamental questions concerning the operational mechanism, causation, and predictability of the most frequent transitional events of the Earth's magnetic field. Geomagnetic excursions are episodes of low field intensity globally with no complete polarity reversals but anomalous magnetic directions that do not reflect a dipolar field. They reduce the shielding against solar and cosmic radiation, thus triggering significant technological and potential environmental and climatic impacts. Our understanding of geomagnetic excursions is severely limited. The urgency to study these events arises from several facts, including the substantial decrease in geomagnetic field strength over the past centuries, certain future events considering the dynamic nature of excursions, and harmful effects on modern technology. To advance in this subject, we must understand the core dynamics and global and regional characteristics of as many of these events as possible. This project focuses on the geomagnetic excursions in the Brunhes Chron (past 780,000 years). I will build the first data-based model of the geomagnetic field over the Brunhes Chron, complemented with high-resolution reconstructions of excursions. These models will be assimilated into state-of-the-art 3D dynamo simulations to infer the excursional state of the core and geodynamo. Furthermore, novel machine learning methods will be applied to the new models to assess past field configurations that resemble the present-day and identify common characteristics and potential precursors of the excursions. This ground-breaking synthesis of multi excursional events analyzed with data-based reconstructions, data assimilation by 3D numerical simulations, and machine learning techniques will create a holistic framework and will advance our knowledge beyond the current understanding of the Earth's outer core dynamics.