Quiet Time Geomagnetic Field Variations in the Equatorial East African Region During the Inclining Phase of Solar Cycle 24
International Journal of Astrophysics and Space Science
Volume 4, Issue 2, April 2016, Pages: 21-25
Received: May 23, 2016;
Accepted: Jun. 1, 2016;
Published: Jun. 20, 2016
Views 2066 Downloads 85
Omondi George Erick, Department of Physics and Materials Science, Maseno University, Maseno, Kenya
Baki Paul, Department of Physics and Space Science, Technical University of Kenya, Nairobi, Kenya
Ndinya Boniface, Department of Physics, Masinde Muliro University of Science and Technology, Kakamega, Kenya
In the present paper, geomagnetic field data obtained from magnetometer measurements at two ground based stations have been used to study solar activity dependence of the solar quiet variations. The study has focused on the horizontal component of the geomagnetic field. The data used in the current study was obtained for all quiet periods from the solar minimum year (2009) through the solar maximum year (2014) to the start of the declining phase (year 2015) of Solar Cycle 24. The present study uses the magnetic data from International Real-time Magnetic Observatory Network (INTERMAGNET) station at Addis Ababa (geomagnetic latitude 0.18°N, geomagnetic longitude110.47°E) and MAGnetic Data Acquisition System (MAGDAS) station at Nairobi (geomagnetic latitude 10.65°S, geomagnetic longitude 108.18°E). The amplitude of mean Sq(H) has shown a dependence on local time of the day and solar activity, with peak values occurring between 1100 LT and 1200 LT and increasing with increase in solar activity; attaining highest values during the solar maximum year. Further, the amplitude of mean Sq(H) at Nairobi is higher than the corresponding values at Addis Ababa in the morning hours around 0700-0800 LT. The local time dependence is attributed to the variation in solar heating and ionization rates while the solar activity dependence is attributed to the increase in electron density with increase in solar activity. The larger morning hours’ amplitudes at Nairobi than Addis Ababa are possibly due to counter electrojet effects close to the geomagnetic equator.
Omondi George Erick,
Quiet Time Geomagnetic Field Variations in the Equatorial East African Region During the Inclining Phase of Solar Cycle 24, International Journal of Astrophysics and Space Science.
Vol. 4, No. 2,
2016, pp. 21-25.
Abbas, M., Zaharadeen, Y. J., Joshua, B. and Mohammed, S. (2013). Geomagnetic Field Variations at Low Latitudes along 96 degrees Magnetic Meridian. International Journal of Marine, Atmospheric & Earth Sciences, 1(2): 96-109.
Baumjohann, W. and Treumann, R. A. (1996). Basic Space Plasma Physics. London: Imperial College Press.
Campbell, W. (2003). Introduction to geomagnetic fields (2nd ed.). New York: Cambridge University Press.
Campbell, W. (1989). Quiet Daily Geomagnetic Fields (1sted., Vol. 131). (W. H. Campbell, Ed.) Boston: Birkhiiuser Verlag Basel.
El Hawary et al. (2012). Annual and semi-annual Sq variations at 96° MM MAGDAS I and II stations in Africa. Earth Planets Space, 64, 425–432.
Matsushita, S., and Maeda, H. (1965). On the Geomagnetic Solar Quiet Daily Variation Field during the IGY. Journal of Geophysical Research, 70 (11), 2535-2558.
Rabiu, A. (2001). Seasonal variability of Solar quiet at middle latitudes. Ghana Journal of Science, 41, 15-22.
Rabiu, A. B., Mamukuyomi, A. I. and Joshua, E. O. (2007). Variability of equatorial ionosphere inferred from geomagnetic field measurements. Bull. Astr. Soc. India, 35, 607-618.
Rabiu, A. B., Nagarajan, N., Okeke, F. N., Ariyibi, E. A., Olayanju, G. M., Joshua, E. O. and Chukwuma, V. U. (2007). A Study Of day-to-day variability in geomagnetic field variations in the electrojet zone of Addis Ababa, East Africa. African Journal of Science and Technology (AJST) Science and Engineering Series, 8 (2), 54-63.
Rabiu, A. B., Yumoto, K., Falayi, E. O., Bello, O. R. & MAGDAS/CPMN Group. (2011). Ionosphere over Africa: Results from Geomagnetic Field Measurements During International Heliophysical Year IHY. Sun and Geosphere, 6 (2), 63-66.
Rastogi, R. G. and Iyer, K. N. (1976). Quiet Day Variation of Geomagnetic H-Field at Low latitudes. J. Geomag. Geoelectr., 28, 461-479.
Rastogi, R. G., Kitamura, T. and Kitamura, K. (2004). Geomagnetic field variations at the equatorial electrojet station in Sri Lanka, Peredinia. Annales Geophysicae, 22, 2729-2739.
Takeda, M. and Araki, T. (1985). Electric conductivity of the ionosphere and nocturnal currents. Journal of Atmospheric and Terrestrial Physics, 47 (6), 601-609.
World Data Center for Geomagnetism, Kyoto. (2016). Geomagnetic Data Service. Retrieved January 04, 2016, from http://wdc.kugi.Kyoto-u.ac.jp/cgi-bin/Kp-cgi
Yamazaki, Y. and Kosch, M. J. (2015). The equatorial electrojet during geomagnetic storms and substorms. Journal of Geophysical Research: Space Physics, 120, 2276-2287, doi:10.1002/2014JA020773.
Yamazaki, Y., Yumoto, K., Cardinal, M. G., Fraser, B. J., Hattori, P., Kakinami, Y., Liu, J. Y, Lynn, K. J. W., Marshall, R., McNamara, D., Nagatsuma, T., Nikiforov, V. M., Otadoy, R. E, Ruhimat, M., Shevtsov, B. M., Shiokawa, K., Abe, S., Uozumi, T. & Yoshikawa, A. (2011). An empirical model of the quiet daily geomagnetic field variation. Journal of Geophysical Research, 116 (A10312), doi: 10.1029/2011JA016487.