GPS Amplitude Scintillations over Kampala, Uganda, During 2010-2011

• Autorzy: Akala A. O. , Idolor R. , D'Ujanga F. M. , Doherty P. H.

Identyfikatory

DOI

10.1515/acgeo-2016-0052

• Języki publikacji: EN

Abstrakty

EN

This study characterizes equatorial scintillations at L1/L2 GPS frequency over Kampala (0.30°N, 32.50°E, mag. lat. 9.26°S), Uganda, on different time scales during the minimum and ascending phases of solar cycle 24 (2010-2011). Of all the days investigated, 25 October 2011 recorded the highest occurrence of scintillation, and it was attributed to geomagnetic storm occurrence. We used the data of 25 October to generate plots of the elevation angle and S4 index against local time on a satellite-by-satellite basis, with a view to distinguishing satellites links whose signals were impaired by ionospheric irregularities from those impaired by multipath. Conclusively, GPS amplitude scintillations over Kampala occur predominantly during post sunset hours and decay around midnight. Equinoctial months recorded the highest occurrences of scintillations, while June solstice recorded the least. Scintillation occurrences also increase with solar and geomagnetic activity.

Słowa kluczowe

EN

Africa; equatorial region; irregularities; solar cycle; ionospheric scintillation

PL

Afryka; region równikowy; nieprawidłowości; cykl słoneczny

• Wydawca: Instytut Geofizyki PAN ; Springer
• Czasopismo: Acta Geophysica
• Rocznik: 2016
• Tom: Vol. 64, no. 5
• Strony: 1903--1915
• Opis fizyczny: Bibliogr. 13 poz.

Twórcy

autor

Akala A. O.

• Department of Physics, University of Lagos, Akoka, Yaba, Lagos, Nigeria

autor

Idolor R.

• Department of Physics, University of Lagos, Akoka, Yaba, Lagos, Nigeria

autor

D'Ujanga F. M.

• Department of Physics, Makerere University, Kampala, Uganda

autor

Doherty P. H.

• Institute for Scientific Research, Boston College, Boston, MA, USA

Bibliografia

• Aarons, J. (1982), Global morphology of ionospheric scintillations, Proc. IEEE 70, 4, 360-378, DOI: 10.1109/PROC.1982.12314.
• Akala, A.O., P.H. Doherty, C.E. Valladares, C.S. Carrano, and R. Sheeham (2011), Statistics of GPS scintillations over South America at three levels of solar activity, Radio Sci. 46, 5, RS4018, DOI: 10.1029/2011 RS004678.
• Akala, A.O., and P.H. Doherty (2012), Statistical distribution of GPS amplitude scintillations, J. Atmos. Sol. Terr. Phys. 74, RS4018, 199-211, DOI: 10.1016/j.jastp.2011.11.006.
• Akala, A.O., P.H. Doherty, C.S. Carrano, C.E. Valladares, and K.M. Groves (2012), Impacts of ionospheric scintillations on GPS receivers intended for equatorial aviation applications, Radio Sci. 47, 4, RS4007, DOI: 10.1029/ 2012RS004995.
• Akala, A.O., L.L.N. Amaeshi, P.H. Doherty, K.M. Groves, C.S. Carrano, C.T. Bridgwood, G.K. Seemala, and E.O. Somoye (2014), Characterization of GNSS scintillations over Lagos, Nigeria during the minimum and ascending phases (2009-2011) of solar cycle 24, Adv. Space Res. 53, 1, 37-47, DOI: 10.1016/j.asr.2013.09.034.
• Anderson, D., and G. Haerendel (1979), The motion of depleted plasma regions in the equatorial ionosphere, J. Geophys. Res. 84, NA8, 4251-4256, DOI: 10.1029/JA 088iA/0p08020.
• Basu, S., E.M. Mackenzie, and S. Basu (1988), Ionospheric constraints on VHF/ UHF communications links during solar maximum and minimum periods, Radio Sci. 23, 3, 363-378, DOI: 10.1029/Rs023i003p00363.
• Basu, S., K.M. Groves, S. Basu, and P.J. Sultan (2002), Specification and forecasting of scintillations in communication/navigation links: current status and future plans, J. Atmos. Sol. Terr. Phys. 64, 16, 1745-1754, DOI: 10.1016/s1364-6826 (02)00124-4.
• Chatterjee, S., and S.K. Chakraborty (2013), Variability of ionospheric scintillation near the equatorial anomaly crest of the Indian zone, Ann. Geophys. 31, 4, 697- 711, DOI: 10.5194/angeo-31-691-2013.
• Dubey, S., R. Wahi, and A.K. Gwal (2006), Ionospheric effects of GPS positioning, Adv. Space Res. 38, 11, 2478-2484, DOI: 10.1016/J.asr.2005.07.030.
• Fejer, J.A. et al. (1979), Ionospheric modification and paramectric instabilities, Rev. Geophys. 17, 1, 135-153, DOI: 10.1029/RG017i001p00135.
• Heelis, R.A. (2004), Electrodynamics In low and middle Latitude ionosphere: a tutorial, J. Atmos. Sol. Terr. Phys. 66, 10, 825-838, DOI: 10.1016/j.jastp.2004. 01.034.
• Kelley, M.C. (1989), The Earth’s Ionosphere, Academic Press Inc., London.