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Peculiarities of the Earth magnetic moment change according to the observations at different points of the Earth surface
- Institute of Geology and Minerology SB RAS, Russia
Estimations of local magnetic constant in different regions during one
epoch and of magnetic moment change rate during magnetic observatory
operation with long observation series have been carried out. A number of
interesting regularities have been determined which make us to be more
attentive to the investigation of global and regional peculiarities in
spatial-temporal morphology of the Earth magnetic field. Within the
hypothesis on a single central dipole, it is impossible to explain the
difference in the observable characteristics of the magnetic field by the
Earth surface form and relief. Real distances from this surface to the
center of the Earth differ by not more than 28 km (the top of Chimborazo
Mountain in Ecuador and the ice surface in the North Pole). But for the
same value of central dipole magnetic moment the distance difference to it
from the farthest and the closest points of the Earth surface must exceed
2200 km. The hypothesis on a single shifted dipole also contradicts with
magnetic observatory data transformed into local magnetic constant,
introduced at the beginning of the 20-th century by Bauer L.A. just to
estimate the Earth magnetic moment change in different regions, and
forgotten, to our opinion, unfairly by modern magnetologists. ''Average''
decrease of the Earth magnetic moment with the rate of 5 percent per a
century is, in reality, composed of its increase in some regions with the
rates up to 20 percent per a century and decrease in other regions with
the rates up to 50 percent per a century. For the majority of the magnetic
observatories, magnetic moment change rate also undergoes considerable in
amplitude variations with characteristic time of about 60-100 years.