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TEC

About: TEC is a research topic. Over the lifetime, 5119 publications have been published within this topic receiving 84696 citations.


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Wang, Li, Yuan, Huo, Xingliang, Zishen, Hernandez-Pajares, Ningbo, Yunbin 
01 Jan 2015
TL;DR: In this paper, a spherical harmonic plus generalized trigonometric series functions (SHPTS) approach was proposed to improve the accuracy and resolution of global ionospheric TEC map (GIM).
Abstract: To take maximum advantage of the increasing Global Navigation Satellite Systems (GNSS) data to improve the accuracy and resolution of global ionospheric TEC map (GIM), an approach, named Spherical Harmonic plus generalized Trigonometric Series functions (SHPTS), is proposed by integrating the spherical harmonic and the generalized trigonometric series functions on global and local scales, respectively. The SHPTS-based GIM from January 1st, 2001 to December 31st, 2011 (about one solar cycle) is validated by the ionospheric TEC from raw global GPS data, the GIM released by the current Ionospheric Associate Analysis Center (IAAC), the TOPEX/Poseidon satellite and the DORIS. The present results show that the SHPTS-based GIM over the area where no real data are available has the same accuracy level (approximately 2–6 TECu) to that released by the current IAAC. However, the ionospheric TEC in the SHPTS-based GIM over the area covered by real data is more accurate (approximately 1.5 TECu) than that of the GIM (approximately 3.0 TECu) released by the current IAAC. The external accuracy of the SHPTS-based GIM validated by the TOPEX/Poseidon and DORIS is approximately 2.5–5.5 and 1.5–4.5 TECu, respectively. In particular, the SHPTS-based GIM is the best or almost the best ranked, along with those of JPL and UPC, when they are compared with TOPEX/Poseidon measurements, and the best (in addition to UPC) when they are validated with DORIS data. With the increase in the number of GNSS satellites and contributing stations, the performance of the SHPTS-based GIM can be further improved. The SHPTS-based GIM routinely calculated using global GPS, GLONASS and BDS data will be found at the website http://www.gipp.org.cn.

128 citations

Journal ArticleDOI
TL;DR: In this paper, the authors used data from the Canadian High Arctic Ionospheric Network (CHAIN) to measure amplitude and phase scintillation from L1 GPS signals and total electron content (TEC) from L 1 and L 2 GPS signals.
Abstract: . High-latitude irregularities can impair the operation of GPS-based devices by causing fluctuations of GPS signal amplitude and phase, also known as scintillation. Severe scintillation events lead to losses of phase lock, which result in cycle slips. We have used data from the Canadian High Arctic Ionospheric Network (CHAIN) to measure amplitude and phase scintillation from L1 GPS signals and total electron content (TEC) from L1 and L2 GPS signals to study the relative role that various high-latitude irregularity generation mechanisms have in producing scintillation. In the first year of operation during the current solar minimum the amplitude scintillation has remained very low but events of strong phase scintillation have been observed. We have found, as expected, that auroral arc and substorm intensifications as well as cusp region dynamics are strong sources of phase scintillation and potential cycle slips. In addition, we have found clear seasonal and universal time dependencies of TEC and phase scintillation over the polar cap region. A comparison with radio instruments from the Canadian GeoSpace Monitoring (CGSM) network strongly suggests that the polar cap scintillation and TEC variations are associated with polar cap patches which we therefore infer to be main contributors to scintillation-causing irregularities in the polar cap.

128 citations

Journal ArticleDOI
TL;DR: In this article, the authors use GPS data for comprehensive regional studies at low latitudes, using the GPS observing sites in South America to form reliable total electron content (TEC) values capable of describing the latitudinal, longitudinal, local time, and storm time behavior over the full span of the continent.
Abstract: Routine observations of the ionospherically imposed propagation effects upon GPS satellite signals are available online from the International GPS Service for Geodynamics. With over 200 ground-based stations now reporting data, ionospheric studies ranging from the analysis of single-site observations to the full global network have demonstrated the geophysical science yield possible from this remarkable resource. In this paper we expand on the use of GPS data for comprehensive “regional studies” at low latitudes. Using the GPS observing sites in South America, we show how routine observations are processed to form reliable total electron content (TEC) values capable of describing the latitudinal, longitudinal, local time, and storm time behavior over the full span of the continent. To study the dominant F region structure at low latitudes, the Appleton anomaly, two indices are developed to assess its strength (Is) and asymmetry (Ia). TEC data at 30 s intervals are used to form phase fluctuation indices that capture plasma irregularity patterns at 15-min (fp) and hourly (Fp) time resolution. Tests of Fp at Atlantic and Pacific sector locations show them to reproduce accurately all known occurrence patterns for equatorial spread F (ESF). The use of the three indices (Is,Ia, and Fp) to formulate predictive capabilities for ESF on the basis of the enhancement or suppression of growth rate indicators was not particularly successful.

128 citations

Journal ArticleDOI
TL;DR: In this article, the authors used a simple ionospheric shell model to derive a map of the ionosphere in the northern hemisphere every 12 hours during the January 1-15, 1993, period.
Abstract: Ionospheric total electron content (TEC) data derived from dual- frequency Global Positioning System (GPS) signals from 30 globally distributed network sites are fit to a simple ionospheric shell model, yielding a map of the ionosphere in the northern hemisphere every 12 hours during the January 1-15, 1993, period.

128 citations

Journal ArticleDOI
Abstract: [1] Recent observations have revealed large F-region electron density perturbations (∼100%) and total electron content (TEC) perturbations (∼30%) that appear to be correlated with tsunamis. The characteristic speed and horizontal wavelength of the disturbances are ∼200 m/s and ∼400 km. We describe numerical simulations using our spectral full-wave model (SFWM) of the upward propagation of a spectrum of gravity waves forced by a tsunami, and the interaction of these waves with the F-region ionosphere. The SFWM describes the propagation of linear, steady-state acoustic-gravity waves in a nonisothermal atmosphere with the inclusion of eddy and molecular diffusion of heat and momentum, ion drag, Coriolis force, and height-dependent mean winds. The tsunami is modeled as a deformation of our model lower boundary traveling at the shallow water wave speed of 200 m/s with a maximum vertical displacement of 50 cm and described by a modified Airy function in the horizontal direction. The derived vertical velocity spectrum at the surface describes the forcing at the lower boundary of the SFWM. A steady-state 1-D ionospheric perturbation model is used to calculate the electron density and TEC perturbations. The molecular diffusion strongly damps the waves in the topside (>300-km altitude) ionosphere. In spite of this, the F-region response is large, with vertical displacements of ∼2 to 5 km and electron density perturbations of ∼100%. Mean winds have a profound effect on the ability of the waves to propagate into the F-region ionosphere.

128 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
2023303
2022578
2021284
2020321
2019293
2018272