Wandering of the Geomagnetic polesGeomagnetic polesMagnetic poles are defined in different ways. They are commonly understood as positions on the Earth's surface where the geomagnetic field is vertical (i.e., perpendicular) to the ellipsoid. These north and south positions, called dip poles, do not need to be (and are not currently) antipodal. In principle the dip poles can be found by conducting a magnetic survey to determine where the field is vertical. Other definitions of geomagnetic poles depend on the way the poles are computed from a geomagnetic model. In practice the geomagnetic field is vertical on oval-shaped loci traced on a daily basis, with considerable variation from one day to the next. Experimental observations of dip poles
It has been long understood that dip poles migrate over time.
In 1831, James Clark Ross located the north dip pole position in northern Canada.
Natural Resources Canada (NRCan) tracked the North Magnetic Pole, which is slowly
drifting across the Canadian Arctic, by periodically carrying out magnetic surveys
to reestablish the Pole's location from 1948 to 1994. An international collaboration,
led by a French fundraising association, Poly-Arctique, and involving NRCan,
Institut de Physique du Globe de Paris and Bureau de Recherche Geologique et Miniere,
added two locations of the North Magnetic Pole in 2001 and 2007. |
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