Featured Map for 30 January 2019:
Magnetic Meanderings


Earth's magnetic poles are located near the poles defined by the axis of Earth's rotation but are not at exactly the same location. Moreover, they wander over time (and reverse every few hundred thousand years). Navigation using a magnetic compass must factor in this variance from true north/south. Various mathematical models exist which describe this variation over time, including forecasts of future variations. These include the International Geomagnetic Reference Field (IGRF; IGRF-12 is valid for 1900-2020) and the World Magnetic Model (WMM; WMM2015 is valid for 2015-2020).

The location of the north magnetic pole has been moving from northern Canada towards Siberia for over a century. Recently, the rate of this change has accelerated, to the point where WMM2015 is likely to exceed limits for navigational error before expiring in 2020. As a result, an interim update (WMM2015v2) is being released to correct these errors. The Great Circle Mapper has been updated to use this data for calculations related to magnetic headings.

Today's Featured Map shows the position of the north magnetic pole from 1900 to today, calculated using the IGRF-12 model. The acceleration of the movement is apparent, with the change over the past nine years being nearly as large as the change over the first 50 years of the 1900s. The true north pole is also shown.

References and additional information:


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