Possible influence of ultra-fast Kelvin wave on the equatorial ionosphere evening uplifting

Takahashi, H.; Abdu, M. A.; Wrasse, C. M.; Fechine, J.; Batista, I. S.; Pancheva, D.; Lima, Lourivaldo Mota; Batista, P. P.; Clemesha, B. R.; Shiokawa, K.; Gobbi, D.; Mlynczak, Martin G.; Russell, James M.

doi:10.1186/bf03353162

Cited by 22 publications

(24 citation statements)

References 35 publications

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“…This approximation is necessary in this present study because we do not know the UFK wave amplitudes at the E-region dynamo altitudes. In the TIMED/SABER temperature UFK oscillations, Takahashi et al (2009) found an amplitude of 5 K at 80 km, and an amplitude of 10 K at 120 km. This indicates that the wave amplitude increased with height by a factor of 2 from the 40 km height range.…”

Section: Methodsmentioning

confidence: 99%

“…According to Takahashi et al (2009), the UFK waves can play an important role over the equatorial ionosphere through dynamo effects. The zonal wind in the lower thermosphere could be one of the principal causes of the day-to-day variability in h F. The UFK waves can superimpose onto, and/or modulate the tidal winds (mainly the zonal component), resulting in an electron density variation of the E-layer by the E-region dynamo.…”

Section: Methodsmentioning

confidence: 99%

“…In the Brazilian equatorial region, Takahashi et al (2005Takahashi et al ( , 2006Takahashi et al ( , 2007Takahashi et al ( , 2009 pointed out the occurrence of UFK wave oscillations in both MLT and ionosphere observations. Takahashi et al (2007) applied wavelet analysis to meteor radar wind data from São João do Cariri (7.4 • S, 36.5 • W), ionospheric parameters h F (minimum F layer virtual height) and foF2 (F layer critical frequency) measured by a digissonde installed at Fortaleza (3.9 • S, 38.4 • W), and temperature data from the TIMED/SABER satellite in order to investigate UFK wave oscillations in both mesospheric and ionospheric parameters.…”

Section: Introductionmentioning

confidence: 99%

“…In the present study, we use a numerical model that takes into account the electrodynamical coupling between the lowlatitude E-region and the equatorial F-region (Batista et al, 1986;Carrasco et al, 2007) in order to explain the vertical drift of F-layer observed by Takahashi et al (2007Takahashi et al ( , 2009. The low latitude quiet-time ionospheric electric fields and plasma drifts are driven by the dynamo action of E-and Fregion thermospheric neutral winds.…”

Section: Introductionmentioning

confidence: 99%

“…From the characteristics of the downward phase propagation (wavelength ∼ 40 km), longitudinal and latitudinal extension, the authors concluded that the oscillation was compatible with a 3.5-day Ultra Fast Kelvin wave. In a subsequent work, Takahashi et al (2009) investigated the day-to-day variability of the F2 layer evening uplift which controls the spread F onset time. The results also revealed UFK wave modulations, reinforcing the importance of this kind of wave in the coupling between the neutral and ionized atmosphere.…”

Section: Introductionmentioning

confidence: 99%

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The ultra-fast Kelvin waves in the equatorial ionosphere: observations and modeling

2013

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The main purpose of this study is to investigate the vertical coupling between the mesosphere and lower thermosphere (MLT) region and the ionosphere through ultra-fast Kelvin (UFK) waves in the equatorial atmosphere. The effect of UFK waves on the ionospheric parameters was estimated using an ionospheric model which calculates electrostatic potential in the E-region and solves coupled electrodynamics of the equatorial ionosphere in the E- and F-regions. The UFK wave was observed in the South American equatorial region during February–March 2005. The MLT wind data obtained by meteor radar at São João do Cariri (7.5° S, 37.5° W) and ionospheric F-layer bottom height (<I>h</I>'F) observed by ionosonde at Fortaleza (3.9° S; 38.4° W) were used in order to calculate the wave characteristics and amplitude of oscillation. The simulation results showed that the combined electrodynamical effect of tides and UFK waves in the MLT region could explain the oscillations observed in the ionospheric parameters

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

The ultra-fast Kelvin waves in the equatorial ionosphere: observations and modeling

2013

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Ionospheric response to the ultrafast Kelvin wave in the MLT region

Dou

Lei

et al. 2014

JGR Space Physics

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The modulation of the ultrafast Kelvin wave (UFKW) on the equatorial ionosphere is investigated, using satellite neutral wind and temperature observations in the mesosphere/lower thermosphere (MLT) and ground-based global maps of total electron content (TEC) observations. The UFKW signatures are identified in the least squares fitting spectra for MLT zonal wind, temperature, TEC, and Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC) electron density profiles, providing strong evidence for the neutral-ion coupling through the UFKW. The periods of the UFKW are mostly confined within 2-5.5 days. The UFKW in zonal wind and temperature maximize in the equatorial regions, whereas the UFKW band-pass perturbations in electron density peak at the equatorial ionization anomaly (EIA) crests with minima at the equator. The UFKW band-pass perturbations in TEC show consistent seasonal variability with the UFKW in the MLT region, including the intraseasonal oscillations with periods of 20-70 days. The long-term variability of the absolute UFKW band-pass amplitudes in TEC is in-phase with solar cycle with maximum amplitude of~7-8 (~1-2) total electron content unit (TECU; 1 TECU = 10 16 el m -2 ) during solar maximum (minimum) years, while the relative amplitudes show little solar activity dependence. The COSMIC electron density profiles show that the UFKW band-pass perturbations maximize at~300-400 km with fountain-like spatial distributions, indicating the modulation of the UFKW on the EIA through electrodynamics.

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A comprehensive survey of atmospheric quasi 3 day planetary‐scale waves and their impacts on the day‐to‐day variations of the equatorial ionosphere

et al. 2015

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This study reports a comprehensive survey of quasi 3 day (2.5-4.5 day period) planetary-scale waves in the low-latitude mesosphere and lower thermosphere using the temperature observations from Thermosphere Ionosphere and Mesosphere Electric Dynamics/Sounding of the Atmosphere using Broadband Emission Radiometry throughout 2002-2012. Occurrences and properties of the waves, including the eastward propagating zonal wave numbers of 1-3 (E1-E3) and vertical wavelengths, are determined for each case. The impacts of these waves on the equatorial ionosphere are investigated by searching for the corresponding variations with the same periods and wave numbers in total electron content (TEC) from the concurrent observations of the ground-based GPS network. For a threshold amplitude of 4 K in temperature, a total of 300 waves are identified, of which there are 186 E1, 63 E2, and 51 E3 events. The mean amplitudes and vertical wavelengths of these waves are calculated to be about 7.9 K and 34 km for the E1, 5.7 K and 29 km for the E2, and 5.1 K and 27 km for the E3, having the standard deviations of 1.5 K and 6.5 km, 0.6 K and 5.6 km, and 0.5 K and 6.7 km. Occurrences of the E1 cases are not observed to depend on season, but the large-amplitude (>8 K) cases occur more often during solstices than at equinoxes. Similarly, the E2 and E3 cases are observed to occur most often in January-February and May-August. Among these waves, 199 cases (66%) are found to have the corresponding variations in the equatorial ionosphere with amplitudes ≥4.2% relative to the mean TEC values (corresponding to 90th percentile). Most of these waves have long vertical wavelengths and large amplitudes (∼3 times more than short vertical wavelength and small-amplitude waves). Because no seasonal or solar cycle dependence on the frequency at which these waves have corresponding variations in the ionosphere at this TEC perturbation threshold is observed, we conclude that there is no seasonal and solar cycle dependence on the propagation of such waves from the mesopause region to higher altitudes. We also identify that only 28 cases (19%) of the E1 TEC variations do not correspond to any E1 waves, which is consistent with the hypothesis that E1 waves are the primary cause of E1 TEC variations. Conditions that are favorable for 3 day waves to create ionospheric variations are present approximately two thirds of the time. This study quantifies the importance and frequency of atmospheric quasi 3 day planetary-scale waves on the day-to-day variations of the equatorial ionosphere using a statistical rather than case study approach.

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Possible influence of ultra-fast Kelvin wave on the equatorial ionosphere evening uplifting

Cited by 22 publications

References 35 publications

The ultra-fast Kelvin waves in the equatorial ionosphere: observations and modeling

The ultra-fast Kelvin waves in the equatorial ionosphere: observations and modeling

Ionospheric response to the ultrafast Kelvin wave in the MLT region

A comprehensive survey of atmospheric quasi 3 day planetary‐scale waves and their impacts on the day‐to‐day variations of the equatorial ionosphere

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