The Evolution of the South Atlantic Anomaly by Swarm Data

Abstract:

The South Atlantic Anomaly (SAA) is a large depression of the Earth’s magnetic field strength characterized by values of geomagnetic field intensity around 30% lower than expected for those latitudes and covers a large area in the South Atlantic Ocean and South America. This peculiar feature of the present geomagnetic field has an internal origin in a prominent patch of reversed polarity flux in the Earth’s outer core. The study of the SAA is an important challenge nowadays, not only for the geomagnetic and paleomagnetic community, but also for other areas focused on the Earth Observation because of the reducing protective role of the geomagnetic field against the charged particles coming from the Sun and forming the solar wind. The SAA has showed to be a persistent feature of the geomagnetic field since its extent at the Earth’s surface has increased during the last four centuries and even accelerated more recently. In this context, the ESA Swarm satellite mission is providing detailed measurements of the intensity and directional elements of the geomagnetic field with high-precision and resolution never reached in the former space missions. This work aims to analyze in detail in space and time the SAA from the core-mantle boundary up to satellite altitudes using the dataset provided by the Swarm satellites and all the available ground-based data.