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

1979 ◽  
Vol 84 (A11) ◽  
pp. 6595 ◽  
Author(s):  
Yinn-Nien Huang
Keyword(s):  
Solar Cycle ◽  
Total Electron Content ◽  
Seasonal Variations ◽  
Electron Content ◽  
Total Electron ◽  
Daily Variations

scholarly journals ANALYSES OF TOTAL ELECTRON CONTENT VARIATIONS OVER NORTHERN AND SOUTHERN NIGERIA

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.

scholarly journals Spatial, Seasonal, and Solar Cycle Variations of the Martian Total Electron Content (TEC): Is the TEC a Good Tracer for Atmospheric Cycles?

2018 ◽  
Vol 123 (7) ◽  
pp. 1746-1759 ◽  
Author(s):  
Beatriz Sánchez-Cano ◽  
Mark Lester ◽  
Olivier Witasse ◽  
Pierre-Louis Blelly ◽  
Mikel Indurain ◽  
...  
Keyword(s):  
Solar Cycle ◽  
Total Electron Content ◽  
Electron Content ◽  
Total Electron ◽  
Good Tracer

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

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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