South Atlantic Anomaly
Swarm satellites have observed a weak-field region expanding from 2014 to 2025. This is a recent observational context, not evidence that a reversal is imminent.
ESA Swarm analysis ↗The magnetic poles (dip poles, where the field is vertical) drift by tens of kilometres a year. The trails follow the annual positions modelled by NOAA from 1590 to 2025; white dots are field surveys.
NOAA NCEI annual positions (gufm1 and IGRF models); field surveys listed in the atlas below.