Posted on Feb 5, 2019
As Magnetic North Pole Zooms Toward Siberia, Scientists Update World Magnetic Model
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North is on the move, and that's a problem for your smartphone maps.
Earth's geographic north pole is fixed. But the planet's magnetic north pole — the north that your compass points toward — wanders in the direction of Siberia at a rate of more than 34 miles per year.
That movement may seem slow, but it's forced scientists to update their model of Earth's magnetic field a year earlier than expected, so that navigational services, including map-based phone apps, continue to work accurately.
The drift results from processes taking place at the center of the planet. Molten iron and nickel slosh and spin in the planet's core, essentially serving as a metallic conductor for Earth's magnetic field. Changes in that fluid flow lead to changes in the magnetic field.
As a result of those changes, the accuracy of the National Oceanic Administration's World Magnetic Model (WMM) — a mathematical representation of the magnetic field — slowly deteriorates in the five-year periods between updates.
The next update was due in 2020. But "unplanned variations" have degraded the quality of the WMM so greatly that NOAA published an out-of-cycle update Monday. It was delayed from January by the partial government shutdown.
Earth's geographic north pole is fixed. But the planet's magnetic north pole — the north that your compass points toward — wanders in the direction of Siberia at a rate of more than 34 miles per year.
That movement may seem slow, but it's forced scientists to update their model of Earth's magnetic field a year earlier than expected, so that navigational services, including map-based phone apps, continue to work accurately.
The drift results from processes taking place at the center of the planet. Molten iron and nickel slosh and spin in the planet's core, essentially serving as a metallic conductor for Earth's magnetic field. Changes in that fluid flow lead to changes in the magnetic field.
As a result of those changes, the accuracy of the National Oceanic Administration's World Magnetic Model (WMM) — a mathematical representation of the magnetic field — slowly deteriorates in the five-year periods between updates.
The next update was due in 2020. But "unplanned variations" have degraded the quality of the WMM so greatly that NOAA published an out-of-cycle update Monday. It was delayed from January by the partial government shutdown.
As Magnetic North Pole Zooms Toward Siberia, Scientists Update World Magnetic Model
Posted from npr.org
Science
Canada
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Posted 6 y ago
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A lot of the maps I used in the Marine Corps had publication dates as far back as 1956! I spent time on several land nav courses and when the instructors did *NOT* walk the course beforehand we had an impossibly hard time finding the way-points. Even over 2 or 3 miles you could be off several hundred feet. In wooded terrain that meant you could not just eyeball the "marker".
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How often are the topo maps we use for land nav updated for correction factors? It's no wonder the "Butter" bar keeps getting lost.
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SMSgt Lawrence McCarter
One reason to use current information to account for the shifts that happen in magnetic North where geographic North doesn't change.
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