geomagnetic secular variation

Geomagnetic secular variation refers to the slow, continuous changes in Earth's magnetic field over time. Unlike the quick shifts caused by space weather, these gradual changes happen over decades and are driven by movements in Earth's liquid outer core, which generate the magnetic field. This ongoing evolution causes the magnetic poles to drift and the strength of the field to fluctuate. Scientists monitor these variations to better understand Earth's interior processes and to maintain accurate navigation systems relying on magnetic data.