Non-Random Influence of External Sources on a Geomagnetic Induction Anomaly in the Northern Part of Greenland

• Published in: Geophysical Journal International
• Main Author: Wilhjelm, J.
• Format: Text
• Language: English
• Published: Oxford University Press 1968
• Subjects: Articles; Greenland; Station Nord
• Online Access: http://gji.oxfordjournals.org/cgi/content/short/16/3/259; https://doi.org/10.1111/j.1365-246X.1968.tb00222.x

Various authors have shown that vectors representing changes in the geomagnetic field often tend to lie in or close to a plane. W. D. Parkinson has observed that for coastal observatories this plane almost invariably tilts upwards towards the nearest deep ocean. In the present paper it is demonstrated that a similar effect exists in Greenland at station Nord situated close to the Polar Basin. Furthermore it is shown that the orientation of the preferred plane depends not only on the frequency spectrum of the geomagnetic variations, but also on the directional and non-random characteristics of the external sources. At station Nord these non-random characteristics lead to a diurnal variation in the orientation of the preferred plane which amounts to as much as 15° in tilt and 40° in azimuth. The concept of a ‘magnetic activity ellipsoid’ is introduced in Section 2 as a useful technique for the analysis of changes in the magnetic field. This method is not limited to the investigation of induction effects and might prove useful in other cases where polarization originating from the configuration of the sources can be expected.