Studying the variability in the diurnal and seasonal variations in GPS total electron content over Nigeria

Abstract. The study of diurnal and seasonal variations in total electron content (TEC) over Nigeria has been prompted by the recent increase in the number of GPS continuously operating reference stations (CORSs) across Nigeria as well as the reduced costs of microcomputing. The GPS data engaged in this study were recorded in the year 2012 at nine stations in Nigeria located between geomagnetic latitudes – 4.33 and 0.72° N. The GPS data were used to derive GPS TEC, which was analysed for diurnal and seasonal variations. The results obtained were used to produce local GPS TEC maps and bar charts. The derived GPS TEC across all the stations demonstrates consistent minimum diurnal variations during the pre-sunrise hours 04:00 to 06:00 LT, increases with sharp gradient during the sunrise period (∼ 07:00 to 09:00 LT), attains postnoon maximum at about 14:00 LT, and then falls to a minimum just before sunset. Generally, daytime variations are found to be greater than nighttime variations, which range between 0 and 5 TECU. The seasonal variation depicts a semi-annual distribution with higher values (∼ 25–30 TECU) around equinoxes and lower values (∼ 20–25 TECU) around solstices. The December Solstice magnitude is slightly higher than the June Solstice magnitude at all stations, while March Equinox magnitude is also slightly higher than September Equinox magnitude at all stations. Thus, the seasonal variation shows an asymmetry in equinoxes and solstices, with the month of October displaying the highest values of GPS TEC across the latitudes.

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ANALYSES OF TOTAL ELECTRON CONTENT VARIATIONS OVER NORTHERN AND SOUTHERN NIGERIA

JOURNAL OF RESEARCH AND REVIEW IN SCIENCE ◽

10.36108/jrrslasu/7102/40(0140) ◽

2017 ◽

Vol 4 (1) ◽

Author(s):

Aghogho Ogwala

Keyword(s):

Total Electron Content ◽

Seasonal Variations ◽

Electron Content ◽

Vertical Total Electron Content ◽

Dual Frequency ◽

The South ◽

Total Electron ◽

The North ◽

December Solstice ◽

Latitudinal Difference

Total electron content (TEC) is a parameter of the ionosphere that produces great effect on radio signals. We present the diurnal and seasonal variations of vertical total electron content (vTEC) during the ascending phase of solar cycle 24. A moderate solar activity year (2011) with sunspot number, Rz = 55.7 is used in this study. Total electron content (TEC) deduced from the dual frequency GPS measurements obtained at two ground stations namely: ABUZ (Zaria) with longitude 7.39oE in the north and UNEC (Enugu) with longitude 7.30oE in the south are considered. Both stations are located within the same longitude and has a latitudinal difference of 4.74o in the Nigerian equatorial ionosphere (NEI). Comparison of diurnal and seasonal variations of TEC is carried out for both stations. The diurnal variation of TEC shows a steep increase starting from sunrise, reaching daytime maximum between 13 – 15 LT at UNEC and 14 – 16 LT at ABUZ, then falls to a minimum at sunset. Dawn depression occurred at the same local time of 04 LT at both stations. On a seasonal scale, Pre- and post-midnight values were highest during the Equinoxes, followed by December solstice and least in June Solstice season at ABUZ. Pre- and post-midnight values were also higher during the Equinoxes than the Solstice season at UNEC, although they are about the same range. Also, TEC values are observed to be slightly higher for all hours and seasons at Enugu in the south than Zaria in the north except during March equinox at Zaria where TEC values were higher during the daytime. This implies that there could be little variations in TEC even within the same latitudinal zone.

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Diurnal, seasonal and solar cycle variation of total electron content and comparison with the IRI-2016 model at Birnin Kebbi

10.5194/angeo-2018-134 ◽

2019 ◽

Author(s):

Aghogho Ogwala ◽

Emmanuel Olufemi Somoye ◽

Olugbenga Ogunmudimu ◽

Rasaq Adewemimo Adeniji-Adele ◽

Eugene Ogheneakpobor Onori ◽

...

Keyword(s):

Solar Cycle ◽

Diurnal Variation ◽

Total Electron Content ◽

Electron Content ◽

Total Electron ◽

Equatorial Station ◽

Solar Cycle Variation ◽

June Solstice ◽

December Solstice ◽

Cycle Dependence

Abstract. Total Electron Content (TEC) is an important ionospheric parameter used to monitor possible space weather impacts on satellite to ground communication and satellite navigation system. TEC is modified in the ionosphere by changing solar Extreme Ultra-Violet (EUV) radiation, geomagnetic storms, and the atmospheric waves that propagate up from the lower atmosphere. Therefore, TEC depends on local time, latitude, longitude, season, geomagnetic conditions, solar cycle activity, and condition of the troposphere. A dual frequency GPS receiver located at an equatorial station, Birnin-Kebbi in Northern Nigeria (geographic location: 12.64° N; 4.22° E), has been used to investigate variation of TEC during the period of 2011 to 2014. We investigate the diurnal, seasonal and solar cycle dependence of observed (OBS) TEC and comparison with latest version of International Reference Ionosphere (IRI-2016) model. On a general note, diurnal variation reveals discrepancies between OBS-TEC and IRI-2016 model for all hours of the day except during the post-midnight hours. Slight post-noon peaks in the daytime maximum and post-sunset decrease and enhancement are observed in the diurnal variation of OBS-TEC of some months. On a seasonal scale, we observed that OBS-TEC values were higher in the equinoxes than the solstices only in 2012. Where as in 2011, September equinox and December solstice recorded higher magnitude followed by March equinox and lowest in June solstice. In 2013, December solstice magnitude was highest, followed by the equinoxes and lowest in June solstice. In 2014, March equinox and December solstice magnitude were higher than September equinox and June solstice magnitude. June solstice consistently recorded the lowest values for all the years. OBS-TEC is found to increase from 2011 to 2014, thus revealing solar cycle dependence.

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Variation in total electron content with sunspot number during the ascending and maximum phases of solar cycle 24 at Birnin Kebbi

10.5194/angeo-2018-95 ◽

2018 ◽

Author(s):

Aghogho Ogwala ◽

Emmanuel Olufemi Somoye ◽

Olugbenga Ogunmodimu ◽

Rasaq Adewemimo Adeniji-Adele ◽

Eugene Oghenakpobo Onori ◽

...

Keyword(s):

Solar Cycle ◽

Total Electron Content ◽

Local Time ◽

Satellite Navigation ◽

Electron Content ◽

Total Electron ◽

June Solstice ◽

December Solstice ◽

Radio Signals ◽

The Impact

Abstract. Satellite radio signals are affected by the presence of electrons in the earth’s upper atmosphere (ionosphere). The more electrons in the path of the satellite radio signals, the more the impact on the accuracy of satellite navigation systems such as the Global Positioning System (GPS)/ Global Navigation Satellite System (GNSS) and GLONASS. These electrons introduce several meters of error in position calculation. Total Electron Content (TEC) is used to monitor possible space weather impacts on satellite to ground communication and satellite navigation. TEC is modified in the ionosphere by changing solar Extreme Ultra-Violet (EUV) radiation, geomagnetic storms, and the atmospheric waves that propagate up from the lower atmosphere. Therefore, TEC depends on local time, latitude, longitude, season, geomagnetic conditions, solar cycle activity, and condition of the troposphere. A dual frequency GPS receiver located at an equatorial station, Birnin-Kebbi in Northern Nigeria (geographic location: 12.64° N; 4.22° E), has been used to investigate variation of TEC during the period of 2011 to 2014. We investigate the diurnal, seasonal and solar cycle dependence of GPS-TEC. The result shows that TEC increases from a minimum at 0400 local time (LT) to maximum daytime peak between 1300–1600 LT and then decreases to a minimum value after sunset for all the years. Slight post-noon peaks in the daytime maximum and post-sunset decrease and enhancement is observed in some months. We observed that TEC were higher in the equinoxes than the solstices only in 2012. Where as in 2011, September equinox and December solstice recorded higher magnitude followed by March equinox and lowest in June solstice. In 2013, December solstice magnitude was highest, followed by the equinoxes and lowest in June solstice. In 2014, March equinox and December solstice magnitude were higher than September equinox and June solstice magnitude. June solstice consistently recorded the lowest values for all the years.

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Diurnal, seasonal and solar cycle variation in total electron content and comparison with IRI-2016 model at Birnin Kebbi

Annales Geophysicae ◽

10.5194/angeo-37-775-2019 ◽

2019 ◽

Vol 37 (5) ◽

pp. 775-789 ◽

Cited By ~ 3

Author(s):

Aghogho Ogwala ◽

Emmanuel Olufemi Somoye ◽

Olugbenga Ogunmodimu ◽

Rasaq Adewemimo Adeniji-Adele ◽

Eugene Oghenakpobor Onori ◽

...

Keyword(s):

Solar Cycle ◽

Diurnal Variation ◽

Total Electron Content ◽

Electron Content ◽

Dual Frequency ◽

Total Electron ◽

Solar Cycle Variation ◽

Cycle Variation ◽

June Solstice ◽

December Solstice

Abstract. The ionosphere is the major error source for the signals of global positioning system (GPS) satellites. In the analysis of GPS measurements, ionospheric error is assumed to be somewhat of a nuisance. The error induced by the ionosphere is proportional to the number of electrons along the line of sight (LOS) from the satellite to receiver and can be determined in order to study the diurnal, seasonal, solar cycle and spatial variations in the ionosphere during quiet and disturbed conditions. In this study, we characterize the diurnal, seasonal and solar cycle variation in observed total electron content (OBS-TEC) and compare the results with the International Reference Ionosphere (IRI-2016) model. We obtained TEC from a dual-frequency GPS receiver located at Birnin Kebbi Federal Polytechnic (BKFP) in northern Nigeria (geographic location: 12.64∘ N, 4.22∘ E; 2.68∘ N dip) for the period 2011–2014. We observed differences between the diurnal variation in OBS-TEC and the IRI-2016 model for all hours of the day except during the post-midnight hours. Slight post-noon peaks in the daytime maximum and post-sunset decrease and enhancement are observed in the diurnal variation in OBS-TEC during the equinoxes. On a seasonal scale, we observed that OBS-TEC values were higher in the equinoxes than the solstices only in 2012. However, in 2011, the September equinox and December solstice recorded a higher magnitude, followed by the March equinox, and the magnitude was lowest in the June solstice. In 2013, the December solstice magnitude was highest, followed by the equinoxes, and it was lowest in the June solstice. In 2014, the March equinox and December solstice magnitudes were higher than the September equinox and June solstice magnitude. The June solstice consistently recorded the lowest values for all the years. OBS-TEC is found to increase from 2011 to 2014, thus revealing solar cycle dependence.

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Variations of the total electron content in the ionosphere from GPS data recorded during the Hector Mine earthquake of October 16, 1999, California

Russian Journal of Earth Sciences ◽

10.2205/2004es000155 ◽

2004 ◽

Vol 6 (5) ◽

pp. 339-354 ◽

Cited By ~ 52

Author(s):

E. L. Afraimovich ◽

E. I. Astafieva ◽

M. B. Gokhberg ◽

V. M. Lapshin ◽

V. E. Permyakova ◽

...

Keyword(s):

Total Electron Content ◽

Gps Data ◽

Electron Content ◽

Total Electron

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Solar cycle and seasonal variations of the solar and lunar daily variations of total electron content at Lunping

Journal of Geophysical Research Atmospheres ◽

10.1029/ja084ia11p06595 ◽

1979 ◽

Vol 84 (A11) ◽

pp. 6595 ◽

Cited By ~ 7

Author(s):

Yinn-Nien Huang

Keyword(s):

Solar Cycle ◽

Total Electron Content ◽

Seasonal Variations ◽

Electron Content ◽

Total Electron ◽

Daily Variations

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EFEK CME HALO PENUH PADA IONOSFER LINTANG RENDAH DARI DATA GPS BAKO DI CIBINONG [EFFECT OF FULL HALO CME ON LOW LATITUDE IONOSPHERE FROM BAKO GPS DATA IN CIBINONG]

Jurnal Sains Dirgantara ◽

10.30536/j.jsd.2017.v15.a2735 ◽

2018 ◽

Vol 15 (1) ◽

pp. 51

Author(s):

Fakhrizal Muttaqien ◽

Buldan Muslim

Keyword(s):

Total Electron Content ◽

Geomagnetic Storm ◽

Geomagnetic Disturbance ◽

Main Phase ◽

Gps Data ◽

Electron Content ◽

Ionospheric Storm ◽

Total Electron ◽

Dst Index ◽

Software Analysis

A full halo coronal mass ejections (CMEs) are most energetic solar events that eject huge amount of mass and magnetic fields into heliosphere with 360o angular angle. The full halo CME effect on the ionosphere can be determined from the ionospheric total electron content (TEC) derived from GPS data. GPS data from BAKO station in Cibinong, satellite orbital data (brcd files) and intrumental bias data (DCB files) have been used to obtain TEC using GOPI software. Analysis of the full halo CME data, Dst index, and TEC during October 2003 and February 2014 showed that the full halo CME could cause ionospheric disturbances called ionospheric storms. Magnitude and time delay of the ionospheric storms depended on the full halo CME speed. For the high-speed full halo CME, the negative ionospheric storm generally occured during recovery phase of the geomagnetic storm. When the initial phase of geomagnetic disturbance with increasing Dst index more than +30 nT, the ionospheric storm occured during main phase of geomagnetic disturbance although the main phase of geomagnetic disturbance did not reach geomagnetic storm condition. ABSTRAKCoronal mass ejection (CME) halo penuh merupakan peristiwa matahari berenergi tinggi, yang menyemburkan massa dan medan magnet ke heliosfer dengan sudut angular sebesar 360º. Efek CME halo penuh pada ionosfer dapat diketahui dari Total Electron Content (TEC). Data GPS BAKO di Cibinong, data orbit satelit (file brcd) dan data bias instrumental (file DCB) dapat digunakan untuk penentuan TEC menggunakan software GOPI. Analisis data CME halo penuh, indeks Dst, dan TEC selama bulan Oktober 2003 dan Februari 2014 menunjukkan bahwa CME halo penuh dapat menimbulkan gangguan ionosfer yang disebut badai ionosfer. Besar dan selang waktu badai ionosfer setelah terjadinya CME, tergantung pada kelajuan CME halo penuh. Untuk CME halo penuh berkelajuan tinggi, badai ionosfer negatif umumnya terjadi pada fase pemulihan badai geomagnet. Jika fase awal gangguan geomagnet diawali dengan peningkatan indeks Dst melebihi +30 nT, maka badai ionosfer dapat terjadi pada fase utama gangguan geomagnet walau gangguan geomagnet setelah fase awal tidak mencapai kondisi badai geomagnet.

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Analysis of Total Electron Content (TEC) Near Real Time Using Dual Frequency GPS Data (Study Case: Surabaya)

E3S Web of Conferences ◽

10.1051/e3sconf/20199405005 ◽

2019 ◽

Vol 94 ◽

pp. 05005 ◽

Cited By ~ 2

Author(s):

Mokhamad Nur Cahyadi ◽

Almas Nandityo Rahadyan ◽

Buldan Muslim

Keyword(s):

Total Electron Content ◽

Electromagnetic Waves ◽

Signal Propagation ◽

Gps Data ◽

Electron Content ◽

Dual Frequency ◽

Additional Time ◽

Ionospheric Correction ◽

Total Electron ◽

A Value

Ionosphere is part of the atmospheric layer located between 50 to 1000 km above the earth's surface which consists of electrons that can influence the propagation of electromagnetic waves in the form of additional time in signal propagation, this depends on Total Electron Content (TEC) in the ionosphere and frequency GPS signal. In high positioning precision with GPS, the effect of the ionosphere must be estimated so that ionospheric correction can be determined to eliminate the influence of the ionosphere on GPS observation. Determination of ionospheric correction can be done by calculating the TEC value using dual frequency GPS data from reference stations or models. In making the TEC model, a polynomial function is used for certain hours. The processing results show that the maximum TEC value occurs at noon at 2:00 p.m. WIB for February 13, 2018 with a value of 35,510 TECU and the minimum TEC value occurs in the morning at 05.00 WIB for February 7, 2018 with a value of 2,138 TECU. The TEC model spatially shows the red color in the area of Surabaya and its surroundings for the highest TEC values during the day around 13.00 WIB to 16.00 WIB.

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