The location of the Earth's magnetic poles from circum‐terrestrial observations

The magnetic poles or dip poles are the points on the Earth's surface and circum‐terrestrial area where the magnetic field is vertical, so the horizontal component vanishes. They are not coincident with geomagnetic poles, which are the points where the dipole axis, obtained by analytic models,...

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Bibliographic Details
Published in:Journal of Geophysical Research: Space Physics
Main Authors: Regi, Mauro, Di Mauro, Domenico, Lepidi, Stefania
Other Authors: Istituto Nazionale di Geofisica e Vulcanologia (INGV), Sezione Roma2, Roma, Italia
Format: Article in Journal/Newspaper
Language:English
Published: Wiley Agu 2021
Subjects:
Magnetic poles location
Swarm satellites
Magnetic poles drift
Magnetic anomalies
Antarctic and Arctic polar regions
Monte Carlo test
04.05. Geomagnetism
05.01. Computational geophysics
Antarctic
Arctic
Antarc*
Online Access:http://hdl.handle.net/2122/14295
https://doi.org/10.1029/2020JA028513
Description
Summary:The magnetic poles or dip poles are the points on the Earth's surface and circum‐terrestrial area where the magnetic field is vertical, so the horizontal component vanishes. They are not coincident with geomagnetic poles, which are the points where the dipole axis, obtained by analytic models, intersects the Earth's surface, and their instrumental sampling determination from ad hoc ground surveys is difficult due to the harsh environmental conditions and remoteness of the areas where they are located. In this work, we use magnetic field measurements from ESA's Swarm satellites covering 5 years (2015‐2019), and determine the position of the magnetic poles by modelling the yearly average horizontal magnetic field component through analytic 2D Taylor polynomial fit and finding the locations where this component is minimum. The yearly dip poles positions at average satellites geocentric altitudes are also projected at ground level based on WGS84 geodetic reference system. Reliability of our method is evaluated by an optimized Monte Carlo test applied to combined IGRF model and Swarm data. The availability of several years of data allows us to investigate the long term variation and dynamics of the magnetic poles, also in comparison with the results provided by IGRF model (both IGRF12 and IGRF13). Our results agree with the model, in better accordance in the north hemisphere with IGRF13, indicating that both magnetic poles move in the north‐west direction, with a speed of ∼37‐72 km/y (lower in year 2016) for the north dip pole and of ∼5‐9 km/y for the south one. Published e2020JA028513 1A. Geomagnetismo e Paleomagnetismo JCR Journal

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