Scientists explain magnetic pole’s wanderings

Posted: May 7, 2020 by oldbrew in Geomagnetism, research

Magnetic North on the move [credit: ESA]

They have a go at doing so, anyway. To make it more complicated, the South Magnetic Pole is also moving, but at a much lesser rate.

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.

Using data from satellites that have measured the evolving shape of Earth’s magnetic field over the past 20 years, Dr Livermore and colleagues have attempted to model the North Magnetic Pole’s wanderings.

Continued here.

  1. oldbrew says:

    Does the shape of this graph look somehow familiar to anyone?

  2. Alan says:

    oldbrew: Sure does — see about 2/3 of the way down this article:

  3. tom0mason says:

    The North pole wanders about but so too does the South Atlantic Anomaly (SAA)
    Maybe these scientists could figure out what is happening with the South Atlantic Anomaly (SAA) — .

    The shape of the SAA changes over time. Since its initial discovery in 1958,[7] the southern limits of the SAA have remained roughly constant while a long-term expansion has been measured to the northwest, the north, the northeast, and the east. Additionally, the shape and particle density of the SAA varies on a diurnal basis, with greatest particle density corresponding roughly to local noon. At an altitude of approximately 500 km (310 mi), the SAA spans from −50° to 0° geographic latitude and from −90° to +40° longitude.[8] The highest intensity portion of the SAA drifts to the west at a speed of about 0.3° per year, and is noticeable in the references listed below. The drift rate of the SAA is very close to the rotation differential between the Earth’s core and its surface, estimated to be between 0.3° and 0.5° per year.

    Current literature suggests that a slow weakening of the geomagnetic field is one of several causes for the changes in the borders of the SAA since its discovery. As the geomagnetic field continues to weaken, the inner Van Allen belt gets closer to the Earth, with a commensurate enlargement of the SAA at given altitudes.

  4. HM says:

    “We know why one part of the magnetic field is moving – it’s because the other part of the magnetic field is moving” (paraphrase)

  5. Paul Vaughan says:

    Mayan U

    Mayan 5256 intro left out U & N.

    Net zero balance includes U, which tilts to wards 5258.

    47478.7405787809 = (49188.0648348793)*(45884.2272968667)/((49188.0648348793+45884.2272968667)/2)
    5913.21946605212 = (47478.7405787809)*(5258.32377718179) / (47478.7405787809 – 5258.32377718179)

    147001.351606394 = 4*36750.3379015986 (Suggestions-42 DO)
    6.40245058405984 = (147001.351606394)*(6.40217174588736) / (147001.351606394 – 6.40217174588736)

    6.40939025620035 = (5913.21946605212)*(6.40245058405984) / (5913.21946605212 – 6.40245058405984)
    -0.000008410484 = %error

    0.0370362449869445 = 0.999978614647502 / 27 (see Review below)
    0.0372515003604406 = (6.40939025620035)*(0.0370362449869445) / (6.40939025620035 – 0.0370362449869445)
    0.0745030007208812 = 2*0.0372515003604406

    27.2122210133018 = 365.25*0.0745030007208812
    0.000000048882 = %error

    0.074004917629613 = (11.0696157491918)*(0.0745030007208812) / (11.0696157491918 + 0.0745030007208812)
    27.0302961642162 = 365.25*0.074004917629613

    0.0372515003422313 = 27.212221/2/365.25
    = time between lunar nodes in julian years
    0.999978614647502 = 365.242189/365.25
    = tropical year length in julian years

    ⌊ 0.999978614647502 / 0.0372515003422313 ⌉ = ⌊26.843982268114⌉ = 27
    0.999978614647502 / 27 = 0.0370362449869445
    harmonic of 0.999978614647502 nearest 0.0372515003422313 is 0.999978614647502 / 27 = 0.0370362449869445
    6.40939079526111 = (0.0372515003422313)*(0.0370362449869445) / (0.0372515003422313 – 0.0370362449869445)
    = terrestrial polar motion period

    27.03 days = geocentric solar-equatorial long-run average period

    satUN wants Eur. folk US luck-D-own the dr.reign with UNjust grave IT, but decade AI french L-layer (as in forest soils) cant ignore thermal tides side door ink cove eye deed move UN water on the surf ace.

    EU: No. God’s watchin’ plain ice.

  6. Paul Vaughan says:

    ratChIT’s work’s dawn in won direction
    O-Thor D-wreck-shhUN: no.thing-bot cliques

  7. oldbrew says:

    MAY 13, 2020
    A possible explanation for the Earth’s North magnetic pole moving toward Russia

    The researchers suggest that there are two large lobes of negative magnetic flux at the boundary of the core and the mantle. They further suggest that changes in molten metal flow in the core result in changes in the magnetic flux in the lobes. The position of the pole is determined by the strength of the two lobes—when one gains strength, the other loses strength resulting in the pole moving in the stronger direction. The result is a constant tug-of-war between the two lobes. The current movement is therefore due to one of the lobes gaining the upper hand.

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