International Journal of Astrophysics and Space Science

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Variations of Crest-to-Trough TEC Ratio of the East African Equatorial Anomaly Region

Received: 21 December 2015    Accepted: 29 December 2015    Published: 02 March 2016
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Abstract

In this paper, Vertical Total Electron Content (VTEC) data derived from dual-frequency GPS measurements obtained at two ground stations were used to study the variability of the equatorial ionization anomaly (EIA). The present study only focuses on analysis of the crest-to-trough TEC ratio (TEC-CTR) in the southern crest region. Data used in this study was obtained for the high solar activity year 2012. MAL2 station (Geomag Lat. -12.4°S, Geomag Long. 111.9°E) was considered for the southern crest region whereas ADIS station (Geomag Lat. 0.2°N, Geomag Long. 110.5°E) was considered for the trough region. Diurnal and seasonal variations as well as the dependency of TEC-CTR on solar activity levels were investigated in the present study. The results showed that the diurnal variation pattern of TEC-CTR is characterized by two remarkable peak values, one occurring in the post‐midnight hours around 02: 00-03: 00 UT (05: 00-06: 00 LT) and the second (highest) peak occurred in the post-sunset hours around 18: 00-20: 00 UT (21: 00-23: 00 LT). Seasonal TEC-CTR variations showed a semi-annual variation pattern, with maximum peak values occurring in the equinoctial months. TEC-CTR also revealed an existence of winter anomaly in this region, with higher values of TEC-CTR in the winter solstice than summer solstice. TEC-CTR in the daytime post-noon hours; between 01: 00-04: 00 UT (04: 00-07: 00 LT) does not vary much with the solar activity; however, TEC-CTR in the post-sunset hours; between 16: 00-20: 00 UT (19: 00-23: 00 LT) shows a clear dependence on the solar activity, with its values increasing with solar activity.

DOI 10.11648/j.ijass.20160401.12
Published in International Journal of Astrophysics and Space Science (Volume 4, Issue 1, February 2016)
Page(s) 12-20
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This is an Open Access article, distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution and reproduction in any medium or format, provided the original work is properly cited.

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Copyright © The Author(s), 2024. Published by Science Publishing Group

Keywords

Total Electron Content (TEC), Equatorial Ionization Anomaly (EIA), GPS Measurements, Solar Activity

References
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Author Information
  • Department of Physics, Busitema University, Tororo, Uganda

  • Department of Physics, Mbarara University of Science and Technology, Mbarara, Uganda

  • Department of Physics, Makerere University, Kampala, Uganda

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    Bosco Oryema, Edward Jurua, Nicolausi Ssebiyonga. (2016). Variations of Crest-to-Trough TEC Ratio of the East African Equatorial Anomaly Region. International Journal of Astrophysics and Space Science, 4(1), 12-20. https://doi.org/10.11648/j.ijass.20160401.12

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    Bosco Oryema; Edward Jurua; Nicolausi Ssebiyonga. Variations of Crest-to-Trough TEC Ratio of the East African Equatorial Anomaly Region. Int. J. Astrophys. Space Sci. 2016, 4(1), 12-20. doi: 10.11648/j.ijass.20160401.12

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    Bosco Oryema, Edward Jurua, Nicolausi Ssebiyonga. Variations of Crest-to-Trough TEC Ratio of the East African Equatorial Anomaly Region. Int J Astrophys Space Sci. 2016;4(1):12-20. doi: 10.11648/j.ijass.20160401.12

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  • @article{10.11648/j.ijass.20160401.12,
      author = {Bosco Oryema and Edward Jurua and Nicolausi Ssebiyonga},
      title = {Variations of Crest-to-Trough TEC Ratio of the East African Equatorial Anomaly Region},
      journal = {International Journal of Astrophysics and Space Science},
      volume = {4},
      number = {1},
      pages = {12-20},
      doi = {10.11648/j.ijass.20160401.12},
      url = {https://doi.org/10.11648/j.ijass.20160401.12},
      eprint = {https://download.sciencepg.com/pdf/10.11648.j.ijass.20160401.12},
      abstract = {In this paper, Vertical Total Electron Content (VTEC) data derived from dual-frequency GPS measurements obtained at two ground stations were used to study the variability of the equatorial ionization anomaly (EIA). The present study only focuses on analysis of the crest-to-trough TEC ratio (TEC-CTR) in the southern crest region. Data used in this study was obtained for the high solar activity year 2012. MAL2 station (Geomag Lat. -12.4°S, Geomag Long. 111.9°E) was considered for the southern crest region whereas ADIS station (Geomag Lat. 0.2°N, Geomag Long. 110.5°E) was considered for the trough region. Diurnal and seasonal variations as well as the dependency of TEC-CTR on solar activity levels were investigated in the present study. The results showed that the diurnal variation pattern of TEC-CTR is characterized by two remarkable peak values, one occurring in the post‐midnight hours around 02: 00-03: 00 UT (05: 00-06: 00 LT) and the second (highest) peak occurred in the post-sunset hours around 18: 00-20: 00 UT (21: 00-23: 00 LT). Seasonal TEC-CTR variations showed a semi-annual variation pattern, with maximum peak values occurring in the equinoctial months. TEC-CTR also revealed an existence of winter anomaly in this region, with higher values of TEC-CTR in the winter solstice than summer solstice. TEC-CTR in the daytime post-noon hours; between 01: 00-04: 00 UT (04: 00-07: 00 LT) does not vary much with the solar activity; however, TEC-CTR in the post-sunset hours; between 16: 00-20: 00 UT (19: 00-23: 00 LT) shows a clear dependence on the solar activity, with its values increasing with solar activity.},
     year = {2016}
    }
    

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  • TY  - JOUR
    T1  - Variations of Crest-to-Trough TEC Ratio of the East African Equatorial Anomaly Region
    AU  - Bosco Oryema
    AU  - Edward Jurua
    AU  - Nicolausi Ssebiyonga
    Y1  - 2016/03/02
    PY  - 2016
    N1  - https://doi.org/10.11648/j.ijass.20160401.12
    DO  - 10.11648/j.ijass.20160401.12
    T2  - International Journal of Astrophysics and Space Science
    JF  - International Journal of Astrophysics and Space Science
    JO  - International Journal of Astrophysics and Space Science
    SP  - 12
    EP  - 20
    PB  - Science Publishing Group
    SN  - 2376-7022
    UR  - https://doi.org/10.11648/j.ijass.20160401.12
    AB  - In this paper, Vertical Total Electron Content (VTEC) data derived from dual-frequency GPS measurements obtained at two ground stations were used to study the variability of the equatorial ionization anomaly (EIA). The present study only focuses on analysis of the crest-to-trough TEC ratio (TEC-CTR) in the southern crest region. Data used in this study was obtained for the high solar activity year 2012. MAL2 station (Geomag Lat. -12.4°S, Geomag Long. 111.9°E) was considered for the southern crest region whereas ADIS station (Geomag Lat. 0.2°N, Geomag Long. 110.5°E) was considered for the trough region. Diurnal and seasonal variations as well as the dependency of TEC-CTR on solar activity levels were investigated in the present study. The results showed that the diurnal variation pattern of TEC-CTR is characterized by two remarkable peak values, one occurring in the post‐midnight hours around 02: 00-03: 00 UT (05: 00-06: 00 LT) and the second (highest) peak occurred in the post-sunset hours around 18: 00-20: 00 UT (21: 00-23: 00 LT). Seasonal TEC-CTR variations showed a semi-annual variation pattern, with maximum peak values occurring in the equinoctial months. TEC-CTR also revealed an existence of winter anomaly in this region, with higher values of TEC-CTR in the winter solstice than summer solstice. TEC-CTR in the daytime post-noon hours; between 01: 00-04: 00 UT (04: 00-07: 00 LT) does not vary much with the solar activity; however, TEC-CTR in the post-sunset hours; between 16: 00-20: 00 UT (19: 00-23: 00 LT) shows a clear dependence on the solar activity, with its values increasing with solar activity.
    VL  - 4
    IS  - 1
    ER  - 

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