Scientists explain magnetic pole’s wanderings

Posted: May 14, 2020 by oldbrew in Geomagnetism, research

Magnetic North on the move [credit: ESA]


It’s down to a process known as ‘flux lobe elongation’, according to researchers. They foresee the magnetic north pole travelling a further 390–660 km towards Siberia.
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European scientists think they can now describe with confidence what’s driving the drift of the North Magnetic Pole, says BBC News.

It’s shifted in recent years away from Canada towards Siberia.

And this rapid movement has required more frequent updates to navigation systems, including those that operate the mapping functions in smartphones.

A team, led from Leeds University, says the behaviour is explained by the competition of two magnetic “blobs” on the edge of the Earth’s outer core.

Changes in the flow of molten material in the planet’s interior have altered the strength of the above regions of negative magnetic flux.

“This change in the pattern of flow has weakened the patch under Canada and ever so slightly increased the strength of the patch under Siberia,” explained Dr Phil Livermore.

“This is why the North Pole has left its historic position over the Canadian Arctic and crossed over the International Date Line. Northern Russia is winning the ‘tug of war’, if you like,” he told BBC News.

Earth has three poles at the top of the planet. A geographic pole which is where the planet’s rotation axis intersects the surface. The geomagnetic pole is the location which best fits a classic dipole (its position alters little). And then there is the North Magnetic, or dip, Pole, which is where field lines are perpendicular to the surface.

It is this third pole that has been doing all the movement.

When first identified by explorer James Clark Ross in the 1830s, it was in Canada’s Nunavut territory.

Back then it didn’t wander very far, very fast. But in the 1990s, it took off, racing to ever higher latitudes and crossing the date line in late 2017. In the process, it came to within just a few hundred kilometres of the geographic pole.

Continued here.
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Nature Geoscience article: Recent north magnetic pole acceleration towards Siberia caused by flux lobe elongation.

Comments
  1. oldbrew says:

    From the Geoscience article:
    The present two-patch structure of the high-latitude geomagnetic field then defines two ends of a linear conduit of near-vertical field, along which the north magnetic pole can readily travel.

    Between 1999 and 2019, the Siberian patch showed a slight intensification from a minimum value of −60.5 to −60.6 μT, while the Canadian patch decreased significantly in absolute value from a minimum of −59.6 to −58.0 μT (Fig. 2a, d). Together, these changes caused the north magnetic pole to travel towards Siberia.

  2. tallbloke says:

    Didn’t we already do this one on May 7?

  3. oldbrew says:

    Good spot – my short memory.

    But we get the link to the paper this time 😉

  4. Chaswarnertoo says:

    Thank gawd for tb. Thought I was suffering deja vu, again.

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