Abstract
Data set from three geomagnetic observatories located along the African meridian has been used to carry out an extensive study on the seasonal variability of Sq in horizontal H, declination D, and vertical Z intensity. The stations were managed by the International Centre for Space Weather Science Education ICSWSE, Kyushu University, Japan. Twelve months of data of only quiet days between August 2008 and September 2009 were used in the analysis following Lloyd’s seasonal classification. Seasonal variability was found to exist in all magnetic elements with equinoctial maxima and D-season minimum in the H field. The observed Sq in both D and Z fields has maximum J-season amplitude and minimum during September equinox. Results of the correlation coefficient show strong and positive correlation values between the same elements at different seasons. A poor correlation exists between the H field and other elements at all seasons but D and Z fields are well correlated in some seasons. This depicts some level of the interrelationship among geomagnetic elements at different seasons. Also, the variability in ionospheric current and shift in the relative position of Sq focus is assumed to be responsible for the seasonal variations.
Similar content being viewed by others
REFERENCES
Bartels, J. and Johnston, H.F., Geomagnetic tides in horizontal intensity at Huancayo, J. Geophys. Res., 1940, vol. 45, pp. 269–308.
Bello, O.R., Rabiu, A.B., Yumoto, K., and Yizengaw, E., Mean solar quiet daily variations in the Earth’s magnetic field along East African longitudes, Adv. Space Res., 2013, vol. 54, no. 3, pp. 283–289. https://doi.org/10.1016/j.asr.2013.11.058
Chapman, S., Some phenomena of the upper atmosphere, Proc. Phys. Soc., London, Sect. B, 1951, vol. 64, pp. 833–843.
Chapman, S. and Rajarao, K.O., The H and Z variation along and near-equatorial electrojet in India, Africa, and the Pacific, J. Atmos. Terr. Phys., 1965, vol. 27, pp. 559–581.
Doumouya, V., Vassal, J., Cohen, Y., et al., Equatorial electrojet at African longitudes: First results from magnetic measurements, Ann. Geophys., 1998, vol. 16, pp. 658–676.
Egedal, J., The magnetic diurnal variation of the horizontal force near the magnetic equator, Terr. Magn. Atmos. Electr., 1947, vol. 52, pp. 449–451.
Emila, D.A., and Last, B.J., A study of Sq variation at Addis Ababa, J. Atmos. Terr. Phys., 1975, vol. 39, pp. 375–381.
Forbes, J.M., The equatorial electrojet, Rev. Geophys. Space Phys., 1981, vol. 19, pp. 469–504.
Gauss, C.F., Allgemeine Theorie des Erdmagnetismus, in Resultate aus den Beobachtungen des Magnetischen Vereins in Jahre 1838, Leipzig: Weidmannsche Buchhandlung, 1839, vol.1, pp. 1–57.
Mann, R.J. and Schlapp, D.M., The equatorial electrojet and the day-to-day variability of Sq, J. Atmos. Terr. Phys., 1988, vol. 50, pp. 57–62.
Obiekezie, T.N. and Okeke, F.N., Variations of geomagnetic H, D and Z field intensities on quiet days at West African latitudes, Moldavian J. Phys. Sci., 2009, vol. 8, nos. 3–4, pp. 366–372.
Okeke, F.N., Variability of the horizontal component of geomagnetic element (H) with mean quiet-day variation, Int. J. Geomagn. Aeron., 2006, vol. 6, no. 2, id GI2005.
Okeke, F.N., and Hamano, Y., New features of abnormal quiet days in equatorial regions, Int. J. Geomagn. Aeron., 2000, vol. 2, pp. 109–114.
Okeke, F.N., Onwumechili, C.A. and Rabiu, A.B., Day-to-day variability of geomagnetic hourly amplitudes at low latitude, Geophys. J. Int., 1998, vol. 134, pp. 484–500.
Patil, A., Arora, B.R. and Rastogi, R.G., Daily variation of geomagnetic field near the focus in Sq current System of Indian longitude, Proc. Indian Acad. Sci., 1983, vol. 92, pp. 239–245.
Rabiu, A., Seasonal variability of Sq at middle latitude, Niger. J. Phys., 2002, vol. 14, no. 1, pp. 68–71.
Rabiu, A.B., Mamukuyomi, A.I. and Joshua, E.O., Variability of equatorial ionosphere inferred from geomagnetic field measurements, Bull. Astron. Soc. India, 2007, vol. 35, pp. 607–618.
Schuster, A., The diurnal variation of terrestrial magnetism, Philos. Trans. R. Soc. London, Ser. A, 1889, vol. 180, pp. 467–518.
Schuster, A., The diurnal variation of terrestrial magnetism. Philos. Trans R. Soc. London, Ser. A, 1908, vol. 280, pp. 163–204.
Stewart, B., Hypothetical views regarding the connection between the state of the Sun and the terrestrial magnetism, in Encyclopedia Britannica, 9th ed., 1882, vol. 16, pp. 181–184.
Tarpley, J.D., Seasonal movement of the Sq current foci and related effects in equatorial electrojet, J. Atmos. Terr. Phys., 1973, vol. 35, pp. 1063–1071.
Vestine, E.H., Main geomagnetic field, in The Physics of Geomagnetic Phenomena, Matsushita, S. and Campbell, W.H., Eds., New York: Academic Press, 1967, vol. 1, pp. 181–234.
ACKNOWLEDGMENTS
The Magnetic Data Acquisition System (MAGDAS) data used for this paper are available at the International Center for Space Weather Science and Education (ICSWSE) website http://magdas2.serc.kyushu-u.ac.jp/datausage/index.html upon request from the Project Leader (PL) of MAGDAS/ CPMN observations, A. Yoshikawa. The authors acknowledge the support of the Japan Society for the Promotion of Science (JSPS) Core-to-Core Program, B. Asia-Africa Science Platforms. The MAGDAS/CPMN group at International Center for Space Weather.
Science and Education (ICSWSE), Kyushu University, Japan, and all hosts of MAGDAS facilities at Addis Ababa, Khartoum, and Nairobi are acknowledged for keeping records of magnetic data and making them available for this study.
Author information
Authors and Affiliations
Corresponding authors
Ethics declarations
The authors declare that they have no conflicts of interest.
Rights and permissions
About this article
Cite this article
Femi, O.O., Rabiu, A.B. Seasonal Variabilities of Geomagnetic Field Components and Their Inter-Relationships along African Low Latitudes. Geomagn. Aeron. 62, 961–970 (2022). https://doi.org/10.1134/S0016793222080096
Received:
Revised:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1134/S0016793222080096