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Modeling the ocean effect of geomagnetic storms
Earth, Planets and Space volume 56, pages 525–530 (2004)
Abstract
At coastal sites, geomagnetic variations for periods shorter than a few days are strongly distorted by the conductivity of the nearby sea-water. This phenomena, known as the ocean (or coast) effect, is strongest in the magnetic vertical component. We demonstrate the ability to predict the ocean effect of geomagnetic storms at geomagnetic observatories. The space-time structure of the storm is derived from the horizontal components at worldwide distributed observatories from which we predict the vertical component using a model of the Earth’s conductivity that a) only depends on depth, and b) includes the conductivity of the sea-water. The results for several strong geomagnetic storms (including the “Bastille Day” event of July 14–15, 2000) show much better agreement (improvement by up to a factor of 2.5) between the observed and the modeled magnetic vertical component at coastal sites if the oceans are considered. Our analysis also indicates a significant local time asymmetry (i.e., contributions from spherical harmonics other than P 01 ), especially during the main phase of the storm.
References
Everett, M., S. Constable, and C. Constable, Effects of near-surface conductance on global satellite induction responses, Geophys. J. Int., 153, 277–286, 2003.
Fainberg, E. B., Electromagnetic induction in the world ocean, Geophys. Surveys, 4, 157–171, 1980.
Fujii, I. and A. Schultz, The 3D electromagnetic response of the Earth to ring current and auroral oval excitation, Geophys. J. Int., 151, 689–709, 2002.
Kuvshinov, A. V., D. B. Avdeev, O. V. Pankratov, S. A. Golyshev, and N. Olsen, Modelling electromagnetic fields in 3D spherical Earth using fast integral equation approach, in 3D Electromagnetics, edited by M. S. Zhdanov and P. E. Wannamaker, chap. 3, pp. 43–54, Elsevier, Holland, 2002a.
Kuvshinov, A. V., N. Olsen, D. B. Avdeev, and O. V. Pankratov, Electromagnetic induction in the oceans and the anomalous behaviour of coastal C-responses for periods up to 20 days, Geophys. Res. Lett., 29, doi:10.1029/2001GL014,409, 2002b.
Kuvshinov, A. V., H. Utada, D. Avdeev, and T. Koyama, 3-D modelling and analysis of the Dst C-responses in the North Pacific ocean region, revisited, Geophys. J. Int., 2004 (in review).
Langel, R. A. and R. H. Estes, Large-scale, near-Earth magnetic fields from external sources and the corresponding induced internal field, J. Geophys. Res., 90, 2487–2494, 1985.
Laske, G. and G. Masters, A global digital map of sediment thickness, EOS Trans. AGU, 78, F483, 1997.
Olsen, N., Estimation of C-responses (3 h to 720 h) and the electrical conductivity of the mantle beneath Europe, Geophys. J. Int., 133, 298–308, 1998.
Olsen, N., Induction studies with satellite data, Surveys in Geophysics, 20, 309–340, 1999.
Parkinson, W. D., Introduction to Geomagnetism, Scottish Academic Press, Edinburgh, 1983.
Parkinson, W. D., The global conductivity distribution, Surveys in Geophysics, 9, 235–244, 1987.
Parkinson, W. D. and F. W. Jones, The geomagnetic coast effect, Rev. Geophys., 17, 1999–2015, 1979.
Rikitake, T. and Y. Honkura, Developments in Earth and planetary sciences, in Solid Earth Geomagnetism, edited by T. Rikitake, vol. 5, Terra Scientific Publishing Company, 1985.
Rostoker, G., E. Friedrich, and M. Dobbs, Physics of magnetic storms, in Magnetic Storms, edited by B. T. Tsurutani, W. D. Gonzales, Y. Kamide, and J. K. Arballo, vol. 98 of Geophysical Monograph Series, pp. 149–160, American Geophysical Union, Washington DC, 1997.
Schmucker, U., Magnetic and electric fields due to electromagnetic induction by external sources, in Landolt-Börnstein, New-Series, 5/2b, pp. 100–125, Springer-Verlag, Berlin-Heidelberg, 1985a.
Schmucker, U., Electrical properties of the Earth’s interior, in Landolt-Börnstein, New-Series, 5/2b, pp. 370–397, Springer-Verlag, Berlin-Heidelberg, 1985b.
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Olsen, N., Kuvshinov, A. Modeling the ocean effect of geomagnetic storms. Earth Planet Sp 56, 525–530 (2004). https://doi.org/10.1186/BF03352512
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DOI: https://doi.org/10.1186/BF03352512