Evaluation of Long-Term Variability of Ionospheric Total Electron Content from IRI-2016 Model over the Indian Sub-Continent with a latitudinal chain of Dual-frequency Geodetic GPS Observations during 2002 to 2019

2021 ◽  
Author(s):  
Siva Sai Kumar Rajana ◽  
TS. Shrungeshwara ◽  
Chiranjeevi G Vivek ◽  
Sampad Kumar Panda ◽  
Sridevi Jade
Keyword(s):  
Total Electron Content ◽  
Electron Content ◽  
Dual Frequency ◽  
Total Electron ◽  
Ionospheric Total Electron Content ◽  
Gps Observations

scholarly journals Comparison of simultaneous variations of the ionospheric total electron content and geomagnetic field associated with strong earthquakes

2001 ◽  
Vol 1 (1/2) ◽  
pp. 53-59 ◽  
Author(s):  
Sh. Naaman ◽  
L. S. Alperovich ◽  
Sh. Wdowinski ◽  
M. Hayakawa ◽  
E. Calais
Keyword(s):  
Total Electron Content ◽  
Vertical Displacement ◽  
Temporal Variations ◽  
Electron Content ◽  
Geomagnetic Disturbances ◽  
Total Electron ◽  
Strong Earthquakes ◽  
Ionospheric Total Electron Content ◽  
Geomagnetic Observations ◽  
Gps Observations

Abstract. In this paper, perturbations of the ionospheric Total Electron Content (TEC) are compared with geomagnetic oscillations. Comparison is made for a few selected periods, some during earthquakes in California and Japan and others at quiet periods in Israel and California. Anomalies in TEC were extracted using Global Positioning System (GPS) observations collected by GIL (GPS in Israel) and the California permanent GPS networks. Geomagnetic data were collected in some regions where geomagnetic observatories and the GPS network overlaps. Sensitivity of the GPS method and basic wave characteristics of the ionospheric TEC perturbations are discussed. We study temporal variations of ionospheric TEC structures with highest reasonable spatial resolution around 50 km. Our results show no detectable TEC disturbances caused by right-lateral strike-slip earthquakes with minor vertical displacement. However, geomagnetic observations obtained at two observatories located in the epicenter zone of a strong dip-slip earthquake (Kyuchu, M = 6.2, 26 March 1997) revealed geomagnetic disturbances occurred 6–7 h before the earthquake.

Geometric determination of ionospheric total electron content from dual frequency radar sounding measurements

2019 ◽  
Vol 178 ◽  
pp. 104696 ◽  
Author(s):  
Kirk M. Scanlan ◽  
Cyril Grima ◽  
Gregor Steinbrügge ◽  
Scott D. Kempf ◽  
Duncan A. Young ◽  
...  
Keyword(s):  
Total Electron Content ◽  
Electron Content ◽  
Dual Frequency ◽  
Total Electron ◽  
Ionospheric Total Electron Content

scholarly journals Secular variation and fluctuation of GPS Total Electron Content over Antarctica

2012 ◽  
Vol 8 (S288) ◽  
pp. 322-325 ◽  
Author(s):  
Rui Jin ◽  
Shuanggen Jin
Keyword(s):  
Total Electron Content ◽  
Electron Content ◽  
Dual Frequency ◽  
Total Electron ◽  
Good Opportunity ◽  
Direct Observations ◽  
Secular Variations ◽  
Global Ionospheric Maps ◽  
Continuous Gps

AbstractThe total electron content (TEC) is an important parameters in the Earth's ionosphere, related to various space weather and solar activities. However, understanding of the complex ionospheric environments is still a challenge due to the lack of direct observations, particularly in the polar areas, e.g., Antarctica. Now the Global Positioning System (GPS) can be used to retrieve total electron content (TEC) from dual-frequency observations. The continuous GPS observations in Antarctica provide a good opportunity to investigate ionospheric climatology. In this paper, the long-term variations and fluctuations of TEC over Antarctica are investigated from CODE global ionospheric maps (GIM) with a resolution of 2.5°×5° every two hours since 1998. The analysis shows significant seasonal and secular variations in the GPS TEC. Furthermore, the effects of TEC fluctuations are discussed.

scholarly journals Characteristics of the ionospheric total electron content of the equatorial ionization anomaly in the Asian-Australian region during 1996–2004

2009 ◽  
Vol 27 (10) ◽  
pp. 3861-3873 ◽  
Author(s):  
◽  
◽  
◽  
Keyword(s):  
Total Electron Content ◽  
Local Time ◽  
Dominant Factor ◽  
Electron Content ◽  
Dual Frequency ◽  
Total Electron ◽  
Australian Region ◽  
Ionospheric Total Electron Content ◽  
Equatorial Ionization Anomaly ◽  
Vertical Drift

Abstract. Ionospheric total electron content (TEC) of the equatorial ionization anomaly (EIA) is studied by analyzing dual-frequency signals of the Global Position System (GPS) acquired from a network of receivers around the Asian-Australian region during 1996–2004. The latitude, occurrence time, strength of the most developed EIA crest, and crest-to-trough ratio (CTR) for both the noon and post-sunset sector obtained from a daily TEC contour map have been used to study the solar cycle variations of EIA in the Asian-Australian region. The results reveal that semiannual and seasonal variations were the dominant factor that controls the morphology of the EIA structure which can be identified in the past studies (e.g. Wu et al., 2008). It is also found that the latitude and local time position of the anomaly crest show a hemispheric asymmetry because (a) The northern crest of EIA is expanded during the equinox indicating a weak semiannual variation while the southern crest is inhibited during June–August presenting a strong seasonal variation, and (b) The local time of the northern crest appears ~1.3 h earlier than that of the southern crest in June while showing no difference at December. Solar activity dependence is more evident in the EIA crest region than in the EIA trough region and least in the post-sunset sector at equinox. A seasonal linear relationship is derived between the post-sunset CTR and solar flux, which should be caused by the solar-dependant equatorial E×B vertical drift.

scholarly journals Phase-referenced VLBA Observations of PSRs B1937+21 and B0329+54

1996 ◽  
Vol 160 ◽  
pp. 115-116
Author(s):  
Rachel J. Dewey ◽  
Anthony J. Beasley
Keyword(s):  
Systematic Error ◽  
Reference Frame ◽  
Total Electron Content ◽  
Electron Content ◽  
Dual Frequency ◽  
Calibration Technique ◽  
Total Electron ◽  
Preliminary Results ◽  
Frame Alignment ◽  
Gps Observations

In this paper we present the preliminary results of phase-referenced VLBA observations of two pulsars PSRB1937+21 and PSRB0329+54. Since pulsar observations usually require a lower observing frequency than that used for other astrometric applications, ionospheric delays are a significant source of systematic error. For the observations presented here we used total-electron-content (TEC) measurements derived from dual-frequency GPS observations (Wilson, Mannucci & Edwards, 1995) to calibrate ionospheric delays.Using this calibration technique were able to obtain positions for these two pulsars which we believe to be accurate to approximately 2 mas in each coordinate. With this level of accuracy we expect astrometric pulsar observations to be able to address a variety of interesting issues ranging from reference frame alignment and fundamental astrometry to the origin of pulsar velocities.

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