Variability of VTEC Gradient and TEC Rate Index Over Kisumu, Kenya During Selected Quiet and Storm Days of 2013 and 2014

Uluma Edward; Ndinya Boniface; Omondi George

doi:doi:10.11648/j.ajaa.20190704.13

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Variability of VTEC Gradient and TEC Rate Index Over Kisumu, Kenya During Selected Quiet and Storm Days of 2013 and 2014

Uluma Edward, Ndinya Boniface, Omondi George

Published in American Journal of Astronomy and Astrophysics (Volume 7, Issue 4)

Received: 30 October 2019 Accepted: 26 November 2019 Published: 4 December 2019

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Abstract

Vertical Total electron content (VTEC) gradient or rate of change of TEC (ROT) and total electron content (TEC) rate index or rate of change of TEC index (ROTI) can directly be estimated from receiver independent exchange (RINEX) data and can be used to estimate presence and intensity of ionospheric irregularities. In this paper we present results of the variation of ROT and ROTI over Kisumu, Kenya (Geomagnetic coordinates: 9.64°S, 108.59°E; Geographic coordinates: 0.02°S, 34.6°E) for both selected quiet and disturbed conditions between 1^st January 2013 and 31^st December 2014 using data derived from NovAtel GSV4004B SCINDA-GPS receiver at Kisumu as a step in establishing ionospheric irregularities over Kisumu, Kenya during a high solar activity period of solar cycle 24. ROT was calculated from filtered average daily VTEC data within intervals of 120 seconds while ROTI was computed over 4 minutes window from ROT. ROT and corresponding ROTI for the selected quiet and storm days were plotted against universal time (UT). The presence and intensity of irregularities on the selected quiet and storm days of the years 2013 and 2014 were determined by checking ROT fluctuations and the corresponding ROTI values from the plots. The obtained results showed increased fluctuation of ROT corresponding with large ROTI values after sunset. The selected storm days of the years 2013 and 2014 had higher ROTI values than the selected quiet days of the years 2013 and 2014. The higher ROTI values during the selected storm days may be attributed to the impact of geomagnetic storms brought about by several competing dynamics including Prompt penetration electric field (PPEF), disturbance dynamo electric field (DDEF) and reduction in electron density due to increased recombination rates. The high ROTI values after sunset were a manifestation of post-sunset plasma irregularities. The obtained results also showed a diurnal trend for ROT and ROTI where ROT increased steadily from 0.00UT to around 12:00UT before falling and having an increased fluctuation between 18:00UT and 20:00UT. This corresponded well with low ROTI values between 0:00UT and 16:00UT followed by high ROTI values between 18:00UT and 20:00UT. The diurnal variability of ROT might have resulted from variation of TEC and which was attributed to changes in the intensity of incoming solar radiation.

Published in	American Journal of Astronomy and Astrophysics (Volume 7, Issue 4)
DOI	10.11648/j.ajaa.20190704.13
Page(s)	67-72
Creative Commons	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.
Copyright	Copyright © The Author(s), 2019. Published by Science Publishing Group

Keywords

Ionospheric Irregularities, Total Electron Content, Geomagnetic Storms

References

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APA Style

Uluma Edward, Ndinya Boniface, Omondi George. (2019). Variability of VTEC Gradient and TEC Rate Index Over Kisumu, Kenya During Selected Quiet and Storm Days of 2013 and 2014. American Journal of Astronomy and Astrophysics, 7(4), 67-72. https://doi.org/10.11648/j.ajaa.20190704.13

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ACS Style

Uluma Edward; Ndinya Boniface; Omondi George. Variability of VTEC Gradient and TEC Rate Index Over Kisumu, Kenya During Selected Quiet and Storm Days of 2013 and 2014. Am. J. Astron. Astrophys. 2019, 7(4), 67-72. doi: 10.11648/j.ajaa.20190704.13

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AMA Style

Uluma Edward, Ndinya Boniface, Omondi George. Variability of VTEC Gradient and TEC Rate Index Over Kisumu, Kenya During Selected Quiet and Storm Days of 2013 and 2014. Am J Astron Astrophys. 2019;7(4):67-72. doi: 10.11648/j.ajaa.20190704.13

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@article{10.11648/j.ajaa.20190704.13,
  author = {Uluma Edward and Ndinya Boniface and Omondi George},
  title = {Variability of VTEC Gradient and TEC Rate Index Over Kisumu, Kenya During Selected Quiet and Storm Days of 2013 and 2014},
  journal = {American Journal of Astronomy and Astrophysics},
  volume = {7},
  number = {4},
  pages = {67-72},
  doi = {10.11648/j.ajaa.20190704.13},
  url = {https://doi.org/10.11648/j.ajaa.20190704.13},
  eprint = {https://article.sciencepublishinggroup.com/pdf/10.11648.j.ajaa.20190704.13},
  abstract = {Vertical Total electron content (VTEC) gradient or rate of change of TEC (ROT) and total electron content (TEC) rate index or rate of change of TEC index (ROTI) can directly be estimated from receiver independent exchange (RINEX) data and can be used to estimate presence and intensity of ionospheric irregularities. In this paper we present results of the variation of ROT and ROTI over Kisumu, Kenya (Geomagnetic coordinates: 9.64°S, 108.59°E; Geographic coordinates: 0.02°S, 34.6°E) for both selected quiet and disturbed conditions between 1st January 2013 and 31st December 2014 using data derived from NovAtel GSV4004B SCINDA-GPS receiver at Kisumu as a step in establishing ionospheric irregularities over Kisumu, Kenya during a high solar activity period of solar cycle 24. ROT was calculated from filtered average daily VTEC data within intervals of 120 seconds while ROTI was computed over 4 minutes window from ROT. ROT and corresponding ROTI for the selected quiet and storm days were plotted against universal time (UT). The presence and intensity of irregularities on the selected quiet and storm days of the years 2013 and 2014 were determined by checking ROT fluctuations and the corresponding ROTI values from the plots. The obtained results showed increased fluctuation of ROT corresponding with large ROTI values after sunset. The selected storm days of the years 2013 and 2014 had higher ROTI values than the selected quiet days of the years 2013 and 2014. The higher ROTI values during the selected storm days may be attributed to the impact of geomagnetic storms brought about by several competing dynamics including Prompt penetration electric field (PPEF), disturbance dynamo electric field (DDEF) and reduction in electron density due to increased recombination rates. The high ROTI values after sunset were a manifestation of post-sunset plasma irregularities. The obtained results also showed a diurnal trend for ROT and ROTI where ROT increased steadily from 0.00UT to around 12:00UT before falling and having an increased fluctuation between 18:00UT and 20:00UT. This corresponded well with low ROTI values between 0:00UT and 16:00UT followed by high ROTI values between 18:00UT and 20:00UT. The diurnal variability of ROT might have resulted from variation of TEC and which was attributed to changes in the intensity of incoming solar radiation.},
 year = {2019}
}

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TY  - JOUR
T1  - Variability of VTEC Gradient and TEC Rate Index Over Kisumu, Kenya During Selected Quiet and Storm Days of 2013 and 2014
AU  - Uluma Edward
AU  - Ndinya Boniface
AU  - Omondi George
Y1  - 2019/12/04
PY  - 2019
N1  - https://doi.org/10.11648/j.ajaa.20190704.13
DO  - 10.11648/j.ajaa.20190704.13
T2  - American Journal of Astronomy and Astrophysics
JF  - American Journal of Astronomy and Astrophysics
JO  - American Journal of Astronomy and Astrophysics
SP  - 67
EP  - 72
PB  - Science Publishing Group
SN  - 2376-4686
UR  - https://doi.org/10.11648/j.ajaa.20190704.13
AB  - Vertical Total electron content (VTEC) gradient or rate of change of TEC (ROT) and total electron content (TEC) rate index or rate of change of TEC index (ROTI) can directly be estimated from receiver independent exchange (RINEX) data and can be used to estimate presence and intensity of ionospheric irregularities. In this paper we present results of the variation of ROT and ROTI over Kisumu, Kenya (Geomagnetic coordinates: 9.64°S, 108.59°E; Geographic coordinates: 0.02°S, 34.6°E) for both selected quiet and disturbed conditions between 1st January 2013 and 31st December 2014 using data derived from NovAtel GSV4004B SCINDA-GPS receiver at Kisumu as a step in establishing ionospheric irregularities over Kisumu, Kenya during a high solar activity period of solar cycle 24. ROT was calculated from filtered average daily VTEC data within intervals of 120 seconds while ROTI was computed over 4 minutes window from ROT. ROT and corresponding ROTI for the selected quiet and storm days were plotted against universal time (UT). The presence and intensity of irregularities on the selected quiet and storm days of the years 2013 and 2014 were determined by checking ROT fluctuations and the corresponding ROTI values from the plots. The obtained results showed increased fluctuation of ROT corresponding with large ROTI values after sunset. The selected storm days of the years 2013 and 2014 had higher ROTI values than the selected quiet days of the years 2013 and 2014. The higher ROTI values during the selected storm days may be attributed to the impact of geomagnetic storms brought about by several competing dynamics including Prompt penetration electric field (PPEF), disturbance dynamo electric field (DDEF) and reduction in electron density due to increased recombination rates. The high ROTI values after sunset were a manifestation of post-sunset plasma irregularities. The obtained results also showed a diurnal trend for ROT and ROTI where ROT increased steadily from 0.00UT to around 12:00UT before falling and having an increased fluctuation between 18:00UT and 20:00UT. This corresponded well with low ROTI values between 0:00UT and 16:00UT followed by high ROTI values between 18:00UT and 20:00UT. The diurnal variability of ROT might have resulted from variation of TEC and which was attributed to changes in the intensity of incoming solar radiation.
VL  - 7
IS  - 4
ER  -

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Author Information

Uluma Edward

Department of Physics, Masinde Muliro University of Science & Technology, Kakamega, Kenya
Ndinya Boniface

Department of Physics, Masinde Muliro University of Science & Technology, Kakamega, Kenya
Omondi George

Department of Physics and Materials Science, Maseno University, Maseno, Kenya

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APA Style

Uluma Edward, Ndinya Boniface, Omondi George. (2019). Variability of VTEC Gradient and TEC Rate Index Over Kisumu, Kenya During Selected Quiet and Storm Days of 2013 and 2014. American Journal of Astronomy and Astrophysics, 7(4), 67-72. https://doi.org/10.11648/j.ajaa.20190704.13

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ACS Style

Uluma Edward; Ndinya Boniface; Omondi George. Variability of VTEC Gradient and TEC Rate Index Over Kisumu, Kenya During Selected Quiet and Storm Days of 2013 and 2014. Am. J. Astron. Astrophys. 2019, 7(4), 67-72. doi: 10.11648/j.ajaa.20190704.13

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AMA Style

Uluma Edward, Ndinya Boniface, Omondi George. Variability of VTEC Gradient and TEC Rate Index Over Kisumu, Kenya During Selected Quiet and Storm Days of 2013 and 2014. Am J Astron Astrophys. 2019;7(4):67-72. doi: 10.11648/j.ajaa.20190704.13

Copy | Download

@article{10.11648/j.ajaa.20190704.13,
  author = {Uluma Edward and Ndinya Boniface and Omondi George},
  title = {Variability of VTEC Gradient and TEC Rate Index Over Kisumu, Kenya During Selected Quiet and Storm Days of 2013 and 2014},
  journal = {American Journal of Astronomy and Astrophysics},
  volume = {7},
  number = {4},
  pages = {67-72},
  doi = {10.11648/j.ajaa.20190704.13},
  url = {https://doi.org/10.11648/j.ajaa.20190704.13},
  eprint = {https://article.sciencepublishinggroup.com/pdf/10.11648.j.ajaa.20190704.13},
  abstract = {Vertical Total electron content (VTEC) gradient or rate of change of TEC (ROT) and total electron content (TEC) rate index or rate of change of TEC index (ROTI) can directly be estimated from receiver independent exchange (RINEX) data and can be used to estimate presence and intensity of ionospheric irregularities. In this paper we present results of the variation of ROT and ROTI over Kisumu, Kenya (Geomagnetic coordinates: 9.64°S, 108.59°E; Geographic coordinates: 0.02°S, 34.6°E) for both selected quiet and disturbed conditions between 1st January 2013 and 31st December 2014 using data derived from NovAtel GSV4004B SCINDA-GPS receiver at Kisumu as a step in establishing ionospheric irregularities over Kisumu, Kenya during a high solar activity period of solar cycle 24. ROT was calculated from filtered average daily VTEC data within intervals of 120 seconds while ROTI was computed over 4 minutes window from ROT. ROT and corresponding ROTI for the selected quiet and storm days were plotted against universal time (UT). The presence and intensity of irregularities on the selected quiet and storm days of the years 2013 and 2014 were determined by checking ROT fluctuations and the corresponding ROTI values from the plots. The obtained results showed increased fluctuation of ROT corresponding with large ROTI values after sunset. The selected storm days of the years 2013 and 2014 had higher ROTI values than the selected quiet days of the years 2013 and 2014. The higher ROTI values during the selected storm days may be attributed to the impact of geomagnetic storms brought about by several competing dynamics including Prompt penetration electric field (PPEF), disturbance dynamo electric field (DDEF) and reduction in electron density due to increased recombination rates. The high ROTI values after sunset were a manifestation of post-sunset plasma irregularities. The obtained results also showed a diurnal trend for ROT and ROTI where ROT increased steadily from 0.00UT to around 12:00UT before falling and having an increased fluctuation between 18:00UT and 20:00UT. This corresponded well with low ROTI values between 0:00UT and 16:00UT followed by high ROTI values between 18:00UT and 20:00UT. The diurnal variability of ROT might have resulted from variation of TEC and which was attributed to changes in the intensity of incoming solar radiation.},
 year = {2019}
}

Copy | Download

TY  - JOUR
T1  - Variability of VTEC Gradient and TEC Rate Index Over Kisumu, Kenya During Selected Quiet and Storm Days of 2013 and 2014
AU  - Uluma Edward
AU  - Ndinya Boniface
AU  - Omondi George
Y1  - 2019/12/04
PY  - 2019
N1  - https://doi.org/10.11648/j.ajaa.20190704.13
DO  - 10.11648/j.ajaa.20190704.13
T2  - American Journal of Astronomy and Astrophysics
JF  - American Journal of Astronomy and Astrophysics
JO  - American Journal of Astronomy and Astrophysics
SP  - 67
EP  - 72
PB  - Science Publishing Group
SN  - 2376-4686
UR  - https://doi.org/10.11648/j.ajaa.20190704.13
AB  - Vertical Total electron content (VTEC) gradient or rate of change of TEC (ROT) and total electron content (TEC) rate index or rate of change of TEC index (ROTI) can directly be estimated from receiver independent exchange (RINEX) data and can be used to estimate presence and intensity of ionospheric irregularities. In this paper we present results of the variation of ROT and ROTI over Kisumu, Kenya (Geomagnetic coordinates: 9.64°S, 108.59°E; Geographic coordinates: 0.02°S, 34.6°E) for both selected quiet and disturbed conditions between 1st January 2013 and 31st December 2014 using data derived from NovAtel GSV4004B SCINDA-GPS receiver at Kisumu as a step in establishing ionospheric irregularities over Kisumu, Kenya during a high solar activity period of solar cycle 24. ROT was calculated from filtered average daily VTEC data within intervals of 120 seconds while ROTI was computed over 4 minutes window from ROT. ROT and corresponding ROTI for the selected quiet and storm days were plotted against universal time (UT). The presence and intensity of irregularities on the selected quiet and storm days of the years 2013 and 2014 were determined by checking ROT fluctuations and the corresponding ROTI values from the plots. The obtained results showed increased fluctuation of ROT corresponding with large ROTI values after sunset. The selected storm days of the years 2013 and 2014 had higher ROTI values than the selected quiet days of the years 2013 and 2014. The higher ROTI values during the selected storm days may be attributed to the impact of geomagnetic storms brought about by several competing dynamics including Prompt penetration electric field (PPEF), disturbance dynamo electric field (DDEF) and reduction in electron density due to increased recombination rates. The high ROTI values after sunset were a manifestation of post-sunset plasma irregularities. The obtained results also showed a diurnal trend for ROT and ROTI where ROT increased steadily from 0.00UT to around 12:00UT before falling and having an increased fluctuation between 18:00UT and 20:00UT. This corresponded well with low ROTI values between 0:00UT and 16:00UT followed by high ROTI values between 18:00UT and 20:00UT. The diurnal variability of ROT might have resulted from variation of TEC and which was attributed to changes in the intensity of incoming solar radiation.
VL  - 7
IS  - 4
ER  -

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