ESA’s Swarm Satellites Reveal Detailed Variations in the Earth’s Magnetic Field

Caitlin Dempsey

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Three years of data collection the European Space Agency’s (ESA) Swarm satellites has resulted in the highest resolution map of Earth’s lithospheric magnetic field.  The lithosphere is the rigid outer part of Earth, consisting of the crust and upper mantle.  According to the ESA, he majority of the Earth’s magnetic field is generated deep within the planet due to movements by the molten iron in the outer core.  About 6% is from electric currents in the space surrounding the planet and from magnetised rocks in the upper lithosphere.  The agency was able to map this magnetic field by using data pulled from the trio of Swarm satellites and modeling it historical data from the German CHAMP satellite.  Nils Olsen from the Technical University of Denmark who worked on developing the map explains, “By combining Swarm measurements with historical data from the German CHAMP satellite, and using a new modelling technique, it was possible to extract the tiny magnetic signals of crustal magnetization.”

The new higher resolution map of the Earth’s magnetic field has revealed anomalies in its surface.  For example, the magnetic field is stronger and sharper around the city of Bangui located in Central Africa.  Researchers theorize this may be due to a meteorite hitting the area more than 540 million years ago.

Magnetic anomaly in Bangui. Red indicates areas where the lithospheric magnetic field is positive, while blues show areas where it is negative. Source: ESA/DTU Space/DLR
Magnetic anomaly in Bangui. Red indicates areas where the lithospheric magnetic field is positive, while blues show areas where it is negative. Source: ESA/DTU Space/DLR

The new map was unveiled at the 2017 Swarm Science Meeting in Canada.

More: Unraveling Earth’s Magnetic Field – ESA

Watch the video of the full model:





Red represents areas where the lithospheric magnetic field is positive, while blues show areas where it is negative.

Youtube video

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Caitlin Dempsey

Caitlin Dempsey is a geographer, writer, and founder and editor of Geography Realm. She holds bachelor's and master's degrees in Geography from UCLA and a Master of Library and Information Science (MLIS) from San José State University.

For more than two decades, she has written about geography, maps, geographic information systems (GIS), remote sensing, satellite imagery, and environmental science. Her work focuses on making geography accessible to a broad audience through articles, tutorials, and educational resources.

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