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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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Journal ArticleDOI
TL;DR: In this paper, the authors analyzed the solar activity dependence of the winter anomaly intensity in the ionospheric F2-layer peak electron density (N m F2 ) and in the Total Electron Content (TEC) on a global scale.
Abstract: For the first time, by using a regression procedure, we analyzed the solar activity dependence of the winter anomaly intensity in the ionospheric F2-layer peak electron density (N m F2 ) and in the Total Electron Content (TEC) on a global scale. We used the data from global ionospheric maps for 1998–2015, from GPS radio occultation observations with COSMIC, CHAMP, and GRACE satellites for 2001–2015, and ground-based ionosonde data. The fundamental features of the winter anomaly in N m F2 and in TEC (spatial distribution and solar activity dependence) are similar for these parameters. We determined the regions, where the winter anomaly may be observed in principle, and the solar activity level, at which the winter anomaly may be recorded in different sectors. A growth in geomagnetic disturbance or in the solar activity level is shown to facilitate the winter anomaly intensity increase. Longitudinal variations in the winter anomaly intensity do not conform partly to the generally accepted Rishbeth theory. We consider the obtained results in the context of spatial and solar cycle variations in O/N2 ratio and thermospheric meridional wind. Additionally, we briefly discuss different definitions of the winter anomaly.

33 citations

Journal ArticleDOI
TL;DR: It is shown that SBSN expression was higher in isolated human and mouse TEC than in NEC, and that the AKT pathway was a downstream factor of SBSn.
Abstract: Recent studies have reported that stromal cells contribute to tumor progression. We previously demonstrated that tumor endothelial cells (TEC) characteristics were different from those of normal endothelial cells (NEC). Furthermore, we performed gene profile analysis in TEC and NEC, revealing that suprabasin (SBSN) was upregulated in TEC compared with NEC. However, its role in TEC is still unknown. Here we showed that SBSN expression was higher in isolated human and mouse TEC than in NEC. SBSN knockdown inhibited the migration and tube formation ability of TEC. We also showed that the AKT pathway was a downstream factor of SBSN. These findings suggest that SBSN is involved in the angiogenic potential of TEC and may be a novel TEC marker.

33 citations

Journal ArticleDOI
TL;DR: In this article, the ionospheric effects associated with tsunami-driven gravity waves are modeled and it is shown that the Tohoku-Oki tsunami of 11 March 2011 is associated with variations in the neutral wind leading to plasma velocity variations both perpendicular and parallel to the geomagnetic field.
Abstract: The Naval Research Laboratory first-principles ionosphere model SAMI3 is used to study the ionospheric effects associated with tsunami-driven gravity waves. Specifically, the Tohoku-Oki tsunami of 11 March 2011 is modeled. It is shown that gravity wave-induced variations in the neutral wind lead to plasma velocity variations both perpendicular and parallel to the geomagnetic field. Moreover, the electric field induced by the neutral wind perturbations can map to the conjugate hemisphere. Thus, electron density variations can be generated in both hemispheres which impact the total electron content (TEC) and 6300 A airglow emission. It is found that the TEC exhibits variations of ≲±0.1 total electron content unit (1 TECU = 1016 el m−2) and the 6300 A airglow emission variation is up to ∼±2.5% relative to the unperturbed background airglow.

33 citations

Journal ArticleDOI
TL;DR: In this paper, the spatial characteristic of the front edge of V-shaped disturbances produced by missiles and rockets was first determined by using the GPS total electron content (TEC), and the observed velocities of the missile were 2.8 and 3.2 km/s at that time.
Abstract: [1] Ionospheric disturbances caused by a missile launched from North Korea on 12 December 2012 were investigated by using the GPS total electron content (TEC). The spatial characteristic of the front edge of V-shaped disturbances produced by missiles and rockets was first determined. Considering the launch direction and the height of estimated ionospheric points at which GPS radio signal pierces the ionosphere, the missile passed through the ionosphere at heights of 391, 425, and 435 km at 0056:30, 0057:00, and 0057:30 UT, respectively. The observed velocities of the missile were 2.8 and 3.2 km/s at that time, which was estimated from the traveling speed of the front edge of V-shaped disturbances. Westward and eastward V-shaped disturbances propagated at 1.8–2.6 km/s. The phase velocities of the westward and eastward V-shaped disturbances were much faster than the speed of acoustic waves reported in previous studies, suggesting that sources other than acoustic waves may have played an important role. Furthermore, the plasma density depletion that is often observed following missile and rocket launches was not found. This suggests that the depletion resulting from the missile's exhaust was not strong enough to be observed in the TEC distribution in the topside ionosphere.

33 citations

Journal ArticleDOI
TL;DR: In this paper, a 6-day oscillation with zonal wave number 1 was identified in the global maps of the ionospheric total electron content (TEC) during May 2003.
Abstract: A westward 6 day oscillation with zonal wave number 1 is identified in the global maps of the ionospheric total electron content (TEC) during May 2003. This signature coincides with the wave activities in the mesosphere and lower thermosphere (MLT) region with a similar zonal structure and period, deduced from the temperature and wind observations from the Thermosphere Ionosphere and Mesosphere Electric Dynamics (TIMED) satellite. The vertical wavelength of this 6 day wave is estimated to be ~65 km, which enables it to propagate up into the lower thermosphere and therefore modulate the ionosphere through E region wind dynamo. The zonal wind perturbations of the 6 day wave maximize in the equatorial region with an amplitude of ~30 m/s and the meridional wind perturbations peak at middle latitudes with an amplitude of 15–20 m/s. The 6 day oscillation in TEC peaks at the geomagnetic equatorial ionization anomaly (EIA) crests in both hemispheres with a deep minimum at the equator. The absolute TEC perturbations maximize at ~1400–1800 LT with an amplitude of ~9 (~7) total electron content unit (TECU; 1 TECU = 1016 m−2) in the southern (northern) hemisphere, which account for ~16% (~10%) of the background TEC. Larger relative TEC perturbations of ~20% are found at 0200–0400 LT. The similar wave number-period spectra and the consistent temporal variations of the 6 day periodical signatures in both neutral atmosphere and ionosphere suggest a strong neutral-ion coupling through planetary wave.

33 citations


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