Nighttime enhancements in ionospheric electron content: seasonal and solar cycle variation

1995 ◽  
Vol 13 (3) ◽  
pp. 256-261 ◽  
Author(s):  
S. Jain ◽  
S. K. Vijay ◽  
A. K. Gwal ◽  
Y. N. Huang
Keyword(s):  
Solar Activity ◽  
Solar Cycle ◽  
Negative Correlation ◽  
Electron Content ◽  
Equatorial Anomaly ◽  
Low Latitude ◽  
Solar Cycle Variation ◽  
Latitude Station ◽  
Cycle Variation ◽  
Ionospheric Electron Content

Abstract. Various characteristics of anomalous nighttime enhancement in ionospheric electron content (IEC) at Lunping (14.08°N geomagnetic), a station near the crest of the equatorial anomaly, have been presented by considering the IEC data for the 21st solar cycle. Out of a total of 1053 enhancements, 354 occur in pre-midnight and 699 occur in post-midnight hours, which indicates an overall dominance of post-midnight events at Lunping. The occurrence is more frequent during summer, less during the equinox and least during winter months. All the characteristics of the enhancements have seasonal dependencies and they reach their maximum values during summer months. The occurrence of the pre-midnight events show positive and post-midnight events show negative correlation with solar activity. The results have been discussed and compared with those at low-latitude stations in India and Hawaii and at the mid-latitude station, Tokyo.

scholarly journals Characteristics of VHF radiowave scintillations over a solar cycle (1983−1993) at a low-latitude station: Waltair (17.7°N, 83.3°E)

1997 ◽  
Vol 15 (6) ◽  
pp. 729-733 ◽  
Author(s):  
P. V. S. Rama Rao ◽  
P. T. Jayachandran ◽  
P. Sri Ram ◽  
B. V. Ramana Rao ◽  
D. S. V. V. D. Prasad ◽  
...  
Keyword(s):  
Solar Activity ◽  
Solar Cycle ◽  
High Solar Activity ◽  
Night Time ◽  
Low Latitude ◽  
Latitude Station ◽  
Maximum Occurrence

Abstract. The characteristics of VHF radiowave scintillations at 244 MHz (FLEETSAT) during a complete solar cycle (1983–93) at a low-latitude station, Waltair (17.7°N, 83.3°E), are presented. The occurrence of night-time scintillations shows equinoctial maxima and summer minima in all the epochs of solar activity, and follows the solar activity. The daytime scintillation occurrence is negatively correlated with the solar activity and shows maximum occurrence during the summer months in a period of low solar activity. The occurrence of night-time scintillations is inhibited during disturbed days of high solar activity and enhanced during low solar activity.

Low-Latitude Ionospheric Electron Content Measurements During Half a Solar Cycle

Radio Science ◽  
1969 ◽  
Vol 4 (9) ◽  
pp. 823-828 ◽  
Author(s):  
F. de Mendonça ◽  
I. J. Kantor ◽  
B. R. Clemesha
Keyword(s):  
Solar Cycle ◽  
Electron Content ◽  
Low Latitude ◽  
Ionospheric Electron Content

Solar cycle variation of the GPS cycle slip occurrence in China low-latitude region

Space Weather ◽  
2010 ◽  
Vol 8 (10) ◽  
pp. n/a-n/a ◽  
Author(s):  
D. H. Zhang ◽  
L. Cai ◽  
Y. Q. Hao ◽  
Z. Xiao ◽  
L. Q. Shi ◽  
...  
Keyword(s):  
Solar Cycle ◽  
Cycle Slip ◽  
Low Latitude ◽  
Solar Cycle Variation ◽  
Cycle Variation ◽  
Latitude Region

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

2019 ◽  
Vol 37 (5) ◽  
pp. 775-789 ◽  
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.

Sign in / Sign up

Export Citation Format

Share Document