The South Atlantic Magnetic Anomaly is intensifying over Brazil, according to the US and UK governments
The phenomenon affects the region over Brazil and the South Atlantic, with a significantly weaker Earth's magnetic field compared to other parts of the planet. What implications does it have?
The intriguing magnetic anomaly of the South Atlantic (AMAS) is deepening and expanding, causing growing concern among the scientific community. This phenomenon, which affects the region over Brazil and the South Atlantic, has a significantly weaker terrestrial magnetic field compared to other parts of the planet, resulting in critical impacts for navigation systems.
The exact cause of the AMAS is still unknown, but the intensity of the magnetic field there falls to a third of the world average.
According to the annual report 2023 of the World Magnetic Model (WMM), prepared by the National Centres for Environmental Information (NCEI) and the British Geological Survey (BGS), in 2023 there was a decrease in the intensity of the magnetic field at the surface level of the AMAS. In addition, the centre of the anomaly moved approximately 20 km to the west. "The affected area, determined by the region within the 25,000 nT boundary, has increased by about 7% since 2020," the report highlights.
Impacts on Brazil and global technology
Although the phenomenon does not involve direct risks to human health or to daily activities on the ground, it can cause damage to satellites and affect the propagation of radio waves.
According to the report, "AMAS is deepening and moving to the west, with direct implications for the radiation that can reach the Earth, impacting satellites and the propagation of radio."
According to The Epoch Times, the anomaly directly affects South America, especially Brazil, where the lower intensity of the magnetic field exposes satellites and navigation systems to high levels of cosmic radiation. The weakness of the magnetic field in this region can cause failures in electronic components and on-board systems, negatively affecting critical communication and environmental surveillance technologies, which can cause frequent breakdowns and even the disconnection of equipment. In addition, the anomaly affects the accuracy of navigation systems that depend on accurate magnetic readings, such as compasses.
Reliable WMM model to evaluate the Earth's magnetic field
The WMM is a spherical harmonic model of the Earth's main magnetic field, developed in collaboration between NCEI and the BGS. It is updated every five years to reflect the changes that occur in the magnetic field.
The centre of the anomaly moved approximately 20 km to the west.
"The accuracy of the WMM2020 has been confirmed until 2024, with global errors that remain well below the maximums allowed by US military specifications," the report says. This indicates that the model is still a reliable tool for navigation and the reference of attitude and direction, despite the variations observed in AMAS.
The data used to monitor and predict changes in the magnetic field are collected by the Swarm satellite constellation of the European Space Agency (ESA). These data are essential to understand the dynamics of AMAS and develop strategies to mitigate its negative impacts.
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