INSTANTANEOUS VELOCITY OF MAGNETIC POLES ACCORDING TO GLOBAL MODELS OF THE GEOMAGNETIC FIELD
St. Petersburg Branch of Pushkov Institute of Terrestrial Magnetism, the Ionosphere and Radio Wave Propagation, Russian Academy of Sciences
Journal: Geophysical research
Tome: 25
Number: 2
Year: 2024
Pages: 79-97
UDK: 550.383+550.389
DOI: 10.21455/gr2024.2-5
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Ivanov
S.A S.A. INSTANTANEOUS VELOCITY OF MAGNETIC POLES ACCORDING TO GLOBAL MODELS OF THE GEOMAGNETIC FIELD
// . 2024. Т. 25. № 2. С. 79-97. DOI: 10.21455/gr2024.2-5
@article{Ivanov
S.AINSTANTANEOUS2024,
author = "Ivanov
S.A, S. A.",
title = "INSTANTANEOUS VELOCITY OF MAGNETIC POLES ACCORDING TO GLOBAL MODELS OF THE GEOMAGNETIC FIELD
",
journal = "Geophysical research",
year = 2024,
volume = "25",
number = "2",
pages = "79-97",
doi = "10.21455/gr2024.2-5",
language = "English"
}
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Keywords: magnetic pole, magnetic pole drift, instantaneous drift velocity.
Аnnotation: A new approach is proposed to calculate the instantaneous velocity of magnetic poles. The method uses the spatial distribution of the vector of the horizontal component H, calculated from analytical models of the main geomagnetic field for the current and the nearest epochs. The horizontal component was calculated using the coefficients of two models: IGRF13 and COV-OBSx2. The equation for the velocity of pole movement is obtained from the condition that the horizontal field component at the pole point is equal to zero at any moment in time, what allowed us to determine the directions of instantaneous velocity. To find the position of the pole and the velocity of its movement between epochs, it is proposed to use a Hermite spline, which describes a smooth curve, whose tangent coincides with the velocity vector in each epoch.
It is shown that the velocity vector of the pole movement depends linearly on the derivative of the horizontal component with respect to time and is inversely proportional to the derivative of H with respect to coordinates. It has been established that higher harmonics are primarily responsible for the acceleration of the pole movement. This is due to their significant contribution to the horizontal component in the polar regions. The obtained instantaneous velocities were compared with the average or interval ones, which are determined from the position of the pole for neighboring epochs. When using the IGRF13 model to calculate the coefficients, artifacts were found in the trajectory of the poles: large deviations in both the directions and magnitudes of the instantaneous velocity vectors compared to interval ones. For the COV-OBSx2 model, no such artifacts were found. It has been assumed that the observed systematic differences in the vectors of instantaneous and interval velocities calculated using the IGRF13 model are associated with the methodological features of constructing this model. In particular, the interval between generations of the IGRF13 model is 5 years, while for the
COV-OBSx2 model it is 2 years and splines were used to construct the latter model. It is noted that the direction of interval velocities for these two models can differ by 40°. Limitations on the applicability of the method associated with sudden changes in the trajectory of the pole are determined. In this case, the method may work unstable, since when calculating the time derivatives of the field at a given epoch, models of the nearest epochs are used. In the case of sudden changes in the pole's trajectory, the values of these derivatives strongly depend on the chosen method of numerical differentiation with respect to time. For the reliability of the proposed method, it is required to know the geomagnetic field in the vicinity of the pole at time intervals shorter than that included in the IGRF13 model.
Bibliography: Alken P., Califf S., Chulliat A., Nair M., Schnepf N.R., Varner J., Woods A., Thébault E., Amit H., Langlais B., Saturnino D., Beggan C.D., Brown W.J., Cox G.A., Macmillan S., Finlay C.C., Hammer M.D., Kloss C., Ol-sen N., Toffner-Clausen L., Aubert J., Fournier A., Hulot G., Lesur V., Ropp G., Vigneron P., Gillet N., Huder L., Livermore P.W., Metman M.C., Mound J.E., Lowes F.J., Korte M., Matzka J., Morsch¬hauser A., Rother M., Stolle C., Vervelidou F., Toh H., Chambodut A., Wardinski I., Shen X., Yang Y., Zeren Z., Zhou B., Magnes W., Jager T., Léger J.M., Bondar T.N., Petrov V.G., Minami T., Nakano S., Sanchez S., Wicht J., Baerenzung J., Holschneider M., Kuang W., Sabaka T.J., Tangborn A., Pavón-Carrasco F.J., Marsal S., Torta J.M., Mandea M., Grayver A., Kuvshinov A., International Geomagnetic Reference Field: the thir-teenth generation, Earth, Planets and Space, 2021, vol. 73, pp. 1-25. DOI: 10.1186/s40623-020-01288-x
Bakhvalov N.S., Chislennye metody (Numerical methods), Moscow, Nauka, 1975, 632 p. [In Russian].
Chulliat A., Hulot G., Newitt L.R., Magnetic flux expulsion from the core as a possible cause of the unusually large acceleration of the north magnetic pole during the 1990s, Journal of Geophysical Research: Solid Earth, 2010, vol. 115, 12 p. DOI: 10.1029/2009JB007143
Dawson E., Newitt L.R., The magnetic poles of the Earth, Journal of Geomagnetism and Geoelectricity, 1982, vol. 34, pp. 225-240.
Demina I.M., Nikitina L.V., Farafonova Yu.G., Motion of the North Magnetic Polewithin the Scope of the Dy-namic Modelof the Main Geomagnetic Field Sources, Geomagnetism and Aeronomy, 2007, vol. 47, no. 2, pp. 263-270. DOI: 10.1134/S0016793207020168
Huder L., Gillet N., Finlay C.C., Hammer M.D., Tchoungui H., COV-OBS/x2: 180 years of geomagnetic field evolution from ground-based and satellite observation, Earth, Planets and Space, 2020, vol. 72, 18 p. DOI: 10.1186/s40623-020-01194-2
Jonkers A.R.T., Jackson A., Murray A., Four centuries of geomagnetic data from historical records, Reviews of Geophysics, 2003, vol. 41, no. 2, 37 p. DOI: 10.1029/2002RG000115
Korte M., Mandea M., Magnetic poles and dipole tilt variation over the past decades to millennia, Earth, Plan-ets and Space, 2008, vol. 60, pp. 937-948. DOI: 10.1186/BF03352849
Lepidi S., Di Mauro D., Tozzi R., Cafarella L., De Michelis P., Marzocchett M., Space observations to determine the location of locally vertical geomagnetic field, in Space Weather of the Heliosphere: Processes and forecasts, Proceedings IAU Symposium.V.335, Cambridge, Cambridge University Press, 2018, pp. 135-138. DOI: 10.1017/S1743921317007190
Livermore P.W., Finlay C.C., Bayliff M., Recent north magnetic pole acceleration towards Siberia caused by flux lobe elongation, Nature Geoscience, 2020, vol. 13, no. 5, pp. 387-391. DOI: 10.1038/s41561-020-0570-9
Mandea M., Dormy E., Asymmetric behavior of magnetic dip poles, Earth, Planets and Space, 2003, vol. 55, pp. 153-157. DOI: 10.1186/BF03351742
Merkuriev S.A., Demina I.M., Ivanov S.A., New data on the the South magnetic pole location in comparison with global models, in Materialy XIV shkoly-konferentsii s mezhdunarodnym uchastiem “Problemy Geo-kosmosa – 2022” (Materials of the XIV school-conference with international participation “Problems of Geocosmos – 2022”), St. Petersburg, Scythia-print, 2022, pp. 30-39. [In Russian].
Olsen N., Mandea M., Will the Magnetic North Pole Move to Siberia?, EOS Transactions AGU, 2007, vol. 88, no. 29, 2 p.
Regi M., Di Mauro D., Lepidi S., The location of the Earth's magnetic poles from circum-terrestrial observations, Journal of Geophysical Research: Space Physics, 2021, vol. 126, 19 p. DOI: 10.1029/2020JA028513
Rogers D., Adams J.A., Mathematical elements for computer graphics, New York, McGraw-Hill, 1991, 611 p.
Semakov N.N., Kovalev A.A., Pavlov A.F., Fedotova O.I., Where does the magnetic pole go?, Nauka iz pervykh ruk (First-hand science), 2016, vol. 68, no. 2, pp. 96-107. [In Russian].
Stasiewicz K., Polar Cusp Topology and Position as a Function of Interplanetary Magnetic Field and Magnetic Activity: Comparison of a Model with Viking and other Observations, Journal of Geophysical Research: Space Physics, 1991, vol. 96, 12 p. DOI: 10.1029/91JA01420
Wessel P., Luis J.F., Uieda L., Scharroo R., Wobbe F., Smith W.H.F., Tian D., The Generic Mapping Tools version 6, Geochemistry, Geophysics, Geosystems, 2019, vol. 20, pp. 5556-5564. DOI: 10.1029/2019GC008515
Witze A., Earth's magnetic field is acting up and geologists don't know why, Nature, 2019, vol. 565, pp. 143-144. DOI: 10.1038/d41586-019-00007-1
Bakhvalov N.S., Chislennye metody (Numerical methods), Moscow, Nauka, 1975, 632 p. [In Russian].
Chulliat A., Hulot G., Newitt L.R., Magnetic flux expulsion from the core as a possible cause of the unusually large acceleration of the north magnetic pole during the 1990s, Journal of Geophysical Research: Solid Earth, 2010, vol. 115, 12 p. DOI: 10.1029/2009JB007143
Dawson E., Newitt L.R., The magnetic poles of the Earth, Journal of Geomagnetism and Geoelectricity, 1982, vol. 34, pp. 225-240.
Demina I.M., Nikitina L.V., Farafonova Yu.G., Motion of the North Magnetic Polewithin the Scope of the Dy-namic Modelof the Main Geomagnetic Field Sources, Geomagnetism and Aeronomy, 2007, vol. 47, no. 2, pp. 263-270. DOI: 10.1134/S0016793207020168
Huder L., Gillet N., Finlay C.C., Hammer M.D., Tchoungui H., COV-OBS/x2: 180 years of geomagnetic field evolution from ground-based and satellite observation, Earth, Planets and Space, 2020, vol. 72, 18 p. DOI: 10.1186/s40623-020-01194-2
Jonkers A.R.T., Jackson A., Murray A., Four centuries of geomagnetic data from historical records, Reviews of Geophysics, 2003, vol. 41, no. 2, 37 p. DOI: 10.1029/2002RG000115
Korte M., Mandea M., Magnetic poles and dipole tilt variation over the past decades to millennia, Earth, Plan-ets and Space, 2008, vol. 60, pp. 937-948. DOI: 10.1186/BF03352849
Lepidi S., Di Mauro D., Tozzi R., Cafarella L., De Michelis P., Marzocchett M., Space observations to determine the location of locally vertical geomagnetic field, in Space Weather of the Heliosphere: Processes and forecasts, Proceedings IAU Symposium.V.335, Cambridge, Cambridge University Press, 2018, pp. 135-138. DOI: 10.1017/S1743921317007190
Livermore P.W., Finlay C.C., Bayliff M., Recent north magnetic pole acceleration towards Siberia caused by flux lobe elongation, Nature Geoscience, 2020, vol. 13, no. 5, pp. 387-391. DOI: 10.1038/s41561-020-0570-9
Mandea M., Dormy E., Asymmetric behavior of magnetic dip poles, Earth, Planets and Space, 2003, vol. 55, pp. 153-157. DOI: 10.1186/BF03351742
Merkuriev S.A., Demina I.M., Ivanov S.A., New data on the the South magnetic pole location in comparison with global models, in Materialy XIV shkoly-konferentsii s mezhdunarodnym uchastiem “Problemy Geo-kosmosa – 2022” (Materials of the XIV school-conference with international participation “Problems of Geocosmos – 2022”), St. Petersburg, Scythia-print, 2022, pp. 30-39. [In Russian].
Olsen N., Mandea M., Will the Magnetic North Pole Move to Siberia?, EOS Transactions AGU, 2007, vol. 88, no. 29, 2 p.
Regi M., Di Mauro D., Lepidi S., The location of the Earth's magnetic poles from circum-terrestrial observations, Journal of Geophysical Research: Space Physics, 2021, vol. 126, 19 p. DOI: 10.1029/2020JA028513
Rogers D., Adams J.A., Mathematical elements for computer graphics, New York, McGraw-Hill, 1991, 611 p.
Semakov N.N., Kovalev A.A., Pavlov A.F., Fedotova O.I., Where does the magnetic pole go?, Nauka iz pervykh ruk (First-hand science), 2016, vol. 68, no. 2, pp. 96-107. [In Russian].
Stasiewicz K., Polar Cusp Topology and Position as a Function of Interplanetary Magnetic Field and Magnetic Activity: Comparison of a Model with Viking and other Observations, Journal of Geophysical Research: Space Physics, 1991, vol. 96, 12 p. DOI: 10.1029/91JA01420
Wessel P., Luis J.F., Uieda L., Scharroo R., Wobbe F., Smith W.H.F., Tian D., The Generic Mapping Tools version 6, Geochemistry, Geophysics, Geosystems, 2019, vol. 20, pp. 5556-5564. DOI: 10.1029/2019GC008515
Witze A., Earth's magnetic field is acting up and geologists don't know why, Nature, 2019, vol. 565, pp. 143-144. DOI: 10.1038/d41586-019-00007-1