Acta Geodaetica et Geophysica

, Volume 53, Issue 4, pp 623–637 | Cite as

Ionospheric temporal variations over the region of Turkey: a study based on long-time TEC observations

  • Erman Şentürk
  • Murat Selim Çepni
Original Study


In this study, daily mean vertical total electron content (VTEC) and daily mean 2-h VTEC values were obtained from Center for Orbit Determination in Europe–Global Ionosphere Maps (CODE–GIM) data over the region of Turkey between January 1, 2003, and December 31, 2016. The time interval is sufficient to reflect temporal changes of the ionosphere. The daily mean VTEC data was used to analyze the space weather effects on the VTEC variability and daily mean 2-h VTEC data was utilized to see the pattern of the diurnal, monthly, seasonal and yearly variation of VTEC values. The highest correlation was found between VTEC and F10.7 (r = 0.83). Totally, 40 major geomagnetic storms were identified that 45% of the storms are caused a decrease and 55% of the storms are caused an increase in VTEC variation. The maximum VTEC is shown at 13:00 LT and the minimum VTEC is shown at 03:00 LT according to diurnal variation of the 14-year mean 2-h VTEC. The maximum VTEC is shown on April and the minimum VTEC is shown on July according to diurnal variation of monthly mean VTEC. Diurnal variation of seasonal mean VTEC and its standard deviations are higher in equinox than solstices. Diurnal variation of yearly mean VTEC has a significant change from low to high solar activity periods.


CODE–GIM Mid-latitude Ionosphere Space-weather Temporal variation 


  1. Adeniyi JO, Ikubanni SO (2013) Determination of the threshold value of F10.7 in the dependence of foF2 on solar activity. Adv Space Res 51(9):1709–1714CrossRefGoogle Scholar
  2. Ansari K, Corumluoglu O, Panda SK (2017) Analysis of ionospheric TEC from GNSS observables over the Turkish region and predictability of IRI and SPIM models. Astrophys Space Sci 362(4):65CrossRefGoogle Scholar
  3. Bagiya MS, Joshi HP, Iyer KN, Aggarwal M, Ravindran S, Pathan BM (2009) TEC variations during low solar activity period (2005–2007) near the equatorial ionospheric anomaly crest region in India. Ann Geophys 27(3):1047–1057CrossRefGoogle Scholar
  4. Chakrabarty D, Bagiya MS, Thampi SV, Iyer KN (2012) Solar EUV flux (0.1–50 nm), F10.7 cm flux, sunspot number and the total electron content in the crest region of equatorial ionization anomaly during the deep minimum between solar cycle 23 and 24. Indian J Radio Space Phys 41:110–120Google Scholar
  5. de Abreu AJ, Martin IM, Fagundes PR, Venkatesh K, Batista IS, de Jesus R, Rockenback M, Coster A, Gende M, Alves MA, Wild M (2017) Ionospheric F-region observations over American sector during an intense space weather event using multi-instruments. J Atmos Solar Terr Phys 156:1–14CrossRefGoogle Scholar
  6. Duncan RA (1969) F-region seasonal and magnetic storm behaviour. J Atmos Terr Phys 31:59–70CrossRefGoogle Scholar
  7. Gopal Rao MSV, Sambasiva Rao R (1969) The hysteresis variation in F2-layer parameters. J Atmos Terr Phys 31(8):1119–1125CrossRefGoogle Scholar
  8. Guo J, Li W, Liu X, Kong Q, Zhao C, Guo B (2015) Temporal–spatial variation of global GPS-derived total electron content, 1999–2013. PLoS ONE 10(7):e0133378CrossRefGoogle Scholar
  9. Hofmann-Wellenhof B, Lichtenegger H, Collins J (1992) Global positioning system theory and practice. Springer, New YorkCrossRefGoogle Scholar
  10. Inyurt S, Mekik C, Yildirim O (2015) Monitoring ionospheric variation for a definite period time in Turkey. Int Arch Photogramm Remote Sens Spat Inf Sci 40(1):339–342CrossRefGoogle Scholar
  11. Jakowski N, Wilken V, Schlueter S et al (2005) Ionospheric space weather effects monitored by simultaneous ground and space based GNSS signals. J Atmos Sol Terr Phys 67(12):1074–1084CrossRefGoogle Scholar
  12. Klobuchar JA (1996) Ionospheric effects on GPS. In: Parkinson BW, Spilker JJ (eds) Global positioning system: theory and applications, vol 1. American Institute of Aeronautics and Astronautics, Washington, DCGoogle Scholar
  13. Komjathy A, Langley RB (1996) The effect of shell height on high precision ionospheric modelling using GPS. In Proceedings of the 1996 IGS workshop international GPS service for geodynamics (IGS), vol 203Google Scholar
  14. Kuai J, Liu L, Liu J, Zhao B, Chen Y, Le H, Wan W (2015) The long-duration positive storm effects in the equatorial ionosphere over Jicamarca. J Geophys Res Space Phys 120(2):1311–1324CrossRefGoogle Scholar
  15. Kumar S, Priyadarshi S, Krishna SG, Singh AK (2012) GPS–TEC variations during low solar activity period (2007–2009) at Indian low latitude stations. Astrophys Space Sci 339(1):165–178CrossRefGoogle Scholar
  16. Li S, Peng J, Xu W, Qin K (2013) Time series modeling and analysis of trends of daily averaged ionospheric total electron content. Adv Space Res 52(5):801–809CrossRefGoogle Scholar
  17. Matsushita S (1959) A study of the morphology of ionospheric storms. J Geophys Res 64(3):305–321CrossRefGoogle Scholar
  18. Millward GH, Moffett RJ, Quegan S, Fuller-Rowell TJ (1996) Ionospheric F2 layer seasonal and semiannual variations. J Geophys Res 101:5149–5156CrossRefGoogle Scholar
  19. Perrone L, De Franceschi G (1998) Solar, ionospheric and geomagnetic indices. Ann Geofis 41(5–6):843–855Google Scholar
  20. Prasad R, Kumar S, Jayachandran PT (2016) Receiver DCB estimation and GPS vTEC study at a low latitude station in the South Pacific. J Atmos Solar Terr Phys 149:120–130CrossRefGoogle Scholar
  21. Prölss GW (1993) On explaining the local time variation of ionospheric storm effects. Ann Geophys 11(1):1–9Google Scholar
  22. Prölss GW (2006) Ionospheric F-region storms: unsolved problems. In: Characterising the ionosphere, proceedings of RTOMP-IST-056, paper 10Google Scholar
  23. Pundhir D, Singh B, Singh OP, Gupta SK (2017) A morphological study of low latitude ionosphere and its implication in identifying earthquake precursors. J Indian Geophys Union 21(3):214–222Google Scholar
  24. Salinas A, Toledo-Redondo S, Navarro EA, Fornieles-Callejón J, Portí JA (2016) Solar storm effects during Saint Patrick’s Days in 2013 and 2015 on the Schumann resonances measured by the ELF station at Sierra Nevada (Spain). J Geophys Res Space Phys. CrossRefGoogle Scholar
  25. Stankov SM, Jakowski N (2007) Ionospheric effects on GNSS reference network integrity. J Atm Sol Terr Phys 69(4–5):485–499CrossRefGoogle Scholar
  26. Stankov SM, Jakowski N, Tsybulya K, Wilken V (2006) Monitoring the generation and propagation of ionospheric disturbances and effects on global navigation satellite system positioning. Radio Sci 41(5):RS6S09. CrossRefGoogle Scholar
  27. Stankov SM, Stegen K, Warnant R (2010) Seasonal variations of storm-time TEC at European middle latitudes. Adv Space Res 46(10):1318–1325CrossRefGoogle Scholar
  28. Tapping KF (2013) The 10.7 cm solar radio flux (F10. 7). Space. Weather 11(7):394–406CrossRefGoogle Scholar
  29. Trichtchenko L, Zhukov A, Van Der Linden R et al (2007) November 2004 space weather events—real time observations and forecasts. Space Weather 5(6):S06001. CrossRefGoogle Scholar
  30. Viereck R, Puga L, McMullin D, Judge D, Weber M, Tobiska WK (2001) The Mg II index: a proxy for solar EUV. Geophys Res Lett 28(7):1343–1346CrossRefGoogle Scholar
  31. Wu CC, Fry CD, Liu JY, Liou K, Tseng CL (2004) Annual TEC variation in the equatorial anomaly region during the solar minimum: September, 1996–August 1997. J Atmos Terr Phys 66:199–207CrossRefGoogle Scholar
  32. Yao Y, Zhai C, Kong J, Liu L (2017) Contribution of solar radiation and geomagnetic activity to global structure of 27-day variation of ionosphere. J Geodesy. CrossRefGoogle Scholar
  33. Yu T, Wan WX, Liu LB, Tang W, Luan XL, Yang GL (2006) Using IGS data to analysis the global TEC annual and semiannual variation. Chin J Geophys 49(4):943–949CrossRefGoogle Scholar

Copyright information

© Akadémiai Kiadó 2018

Authors and Affiliations

  1. 1.Department of Surveying EngineeringKocaeli UniversityKocaeliTurkey

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