Regional geomagnetic field model over the area comprising the South Atlantic Anomaly

Taking advantage of the Swarm three-satellite magnetic field mission by ESA, launched on 22 November 2013 and still orbiting, and ground observatory magnetic data, we determine a spatiotemporal regional model for the geomagnetic field using the R-SCHA technique over the area comprising the South Atlantic Anomaly (SAA). The SAA is the region above the South Atlantic and South America where the geomagnetic field intensity is much lower than expected by a simple dipolar field. Its origin is deep in the outer core and is likely due to a reverse magnetic flux area that has been increasing in the last four centuries. On the basis of this model, we observe 1) the recent evolution of the anomaly from 2014 up to date, with a focus on its “tails” towards South Africa and West Pacific, 2) some features that can be related to important properties of the main geomagnetic field, such as its secular variation and the occurrence of geomagnetic jerks.