Effect of Non‐Dipole Field on VGP Estimation

• Published in: Chinese Journal of Geophysics
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2007
• Subjects: Pacific; Antarc*; Antarctica; Geomagnetic Pole; South Atlantic Ocean
• Online Access: http://dx.doi.org/10.1002/cjg2.1130; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2Fcjg2.1130; https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1002/cjg2.1130

Abstract The virtual geomagnetic pole (VGP) calculated under the assumption of a central dipole field is generally different from the real geomagnetic pole (RGP) since effect of the non‐dipole field. In order to quantitatively examine effects of the non‐dipole field on VGP determination, the VGP and RGP are calculated at 5° × 5° virtual sites by using the IGRF1900~2000 models. The results show significant departures of VGP from RGP in some major magnetic anomaly regions. The latitude departures of VGP from the RGP are as large as 25° in these anomaly regions, although they are acceptable in most sites on the earth's surface (less than 10°), mainly confined in the regions with a weak intensity of the non‐dipole field, such as Pacific Ocean. The longitude departures of VGP from RGP are much more remarkable, scattering in a wide range from –180° to 180° in Eurasian continent. The angle distance between VGP and the RGP are generally within a range of 15°, except the Antarctica, South Atlantic Ocean and Eurasia regions.