Appendix A — Comparing the IRI prediction with the observed equatorial anomaly in the Total Electron Content around 120° E longitude

1996 ◽  
Vol 18 (6) ◽  
pp. 325-326
Author(s):  
Kang Cheng ◽  
Yinn-Nien Huang
Keyword(s):  
Total Electron Content ◽  
Electron Content ◽  
Equatorial Anomaly ◽  
Total Electron

scholarly journals Observations in equatorial anomaly region of total electron content enhancements and depletions

2005 ◽  
Vol 23 (7) ◽  
pp. 2449-2456 ◽  
Author(s):  
N. Dashora ◽  
R. Pandey
Keyword(s):  
Total Electron Content ◽  
Scintillation Index ◽  
Electron Content ◽  
Equatorial Anomaly ◽  
Low Latitude ◽  
Total Electron ◽  
First Results ◽  
Spread F ◽  
New Feature ◽  
Low Latitude Ionosphere

Abstract. A GSV 4004A GPS receiver has been operational near the crest of the equatorial anomaly at Udaipur, India for some time now. The receiver provides the line-of-sight total electron content (TEC), the phase and amplitude scintillation index, σφ and S4, respectively. This paper presents the first results on the nighttime TEC depletions associated with the equatorial spread F in the Indian zone. The TEC depletions are found to be very well correlated with the increased S4 index. A new feature of low-latitude TEC is also reported, concerning the observation of isolated and localized TEC enhancements in the nighttime low-latitude ionosphere. The TEC enhancements are not correlated with the S4 index. The TEC enhancements have also been observed along with the TEC depletions. The TEC enhancements have been interpreted as the manifestation of the plasma density enhancements reported by Le et al. (2003). Keywords. Ionosphere (Equatorial ionosphere; Ionospheric irregularities)

scholarly journals Double-thin-shell approach to deriving total electron content from GNSS signals and implications for ionospheric dynamics near the magnetic equator

2021 ◽  
Vol 73 (1) ◽  
Author(s):  
Takashi Maruyama ◽  
Kornyanat Hozumi ◽  
Guanyi Ma ◽  
Pornchai Supnithi ◽  
Napat Tongkasem ◽  
...  
Keyword(s):  
Total Electron Content ◽  
Thin Shell ◽  
Spherical Surface ◽  
Satellite System ◽  
Electron Content ◽  
Equatorial Anomaly ◽  
Total Electron ◽  
Functional Fitting ◽  
A New Technique ◽  
Global Navigation Satellite

AbstractA new technique was developed to estimate the ionospheric total electron content (TEC) from Global Navigation Satellite System (GNSS) satellite signals. The vertically distributed electron density was parameterized by two thin-shell layers (double-shell approach). The spatiotemporal variation of TEC (strictly speaking, partial electron content) associated with each shell was approximated by the functional fitting of spherical surface harmonics. The major improvements over the conventional single-shell approach were as follows: (1) the precise estimation of TEC was achieved; (2) the estimated TEC was less dependent on the choice of shell heights; and (3) the equatorial anomaly was captured more correctly. Furthermore, higher and lower shells exhibited a different pattern of local time vs latitude variation, providing information on the ionosphere–thermosphere dynamics.

scholarly journals Association of Total Electron Content (TEC) and foF2 variations with earthquake events at the anomaly crest region

2009 ◽  
Vol 47 (1) ◽  
Author(s):  
M. Devi ◽  
A. K. Barbara ◽  
A. Depueva
Keyword(s):  
Electric Field ◽  
Total Electron Content ◽  
Electron Content ◽  
Equatorial Anomaly ◽  
Total Electron ◽  
Methods And Techniques ◽  
Radio Beacon

The paper attempts to identify ionospheric parameters in association with earthquake at anomaly crest station through VHF Radio Beacon data and ground based ionosonde measurements while the Total Electron Content(TEC) parameters from RB observations are based mainly on data taken over Guwahati (26.2°N, 91.75° E), foF2 data used in the analysis were collected at Ahmadabad (23.01°N, 72.36°E). The paper describes methods and techniques adopted to examine modifications on these parameters if any, due to earthquake preparatory processes at equatorial anomaly crest stations. The mechanism of inducement of density changes in the ionosphere is sought through the generation of strong fountain effect possibly by the development of electric field during the earthquake preparatory process.

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