Planetary wave signatures in the equatorial atmosphere–ionosphere system, and mesosphere- E- and F-region coupling

Abdu, M. A.; Ramkumar, T. K.; Batista, I. S.; Brum, C. G. M.; Takahashi, H.; Reinisch, B. W.; Sobral, J. H. A.

doi:10.1016/j.jastp.2005.03.019

Cited by 80 publications

(67 citation statements)

References 39 publications

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“…Recent studies have shown that upward-propagating tides modulate the E-region dynamo electric field and hence the equatorial plasma fountain over the dip equator [Abdu et al, 2006;Immel et al, 2006]. Therefore it can be conjectured that the day-to-day variability in unique equatorial phenomena such as the EEJ is directly connected with the variability in upward-propagating tides.…”

Section: Resultsmentioning

confidence: 99%

“…[17] An explanation for the presence of PWs in the EEJ was given by Abdu et al [2006] in a recent study. The EEJproduced magnetic field represents the diurnal variation in the EEJ, which is a direct measure of the product of dynamo electric field intensity, electron density and conductivity at E-region heights.…”

Section: Resultsmentioning

confidence: 99%

“…Among these, the upward propagating tides play a significant role in shaping the major phenomenology of the equatorial dynamo region on a dayto-day basis [Abdu et al, 2006]. The strength of the EEJ exhibits great seasonal variability, being 1.7-1.8 times greater at equinoxes than at solstices [Reddy, 1989].…”

Section: Introductionmentioning

confidence: 99%

“…These interactions are expected to be more effective in the mesosphere, as both PWs and tidal amplitudes are typically high in this region. In addition to this, the processes involving the PWs and their interaction with tides also are known to have a bearing on the day-to-day variabilities of the daytime equatorial electrodynamics, especially of the EEJ [Abdu et al, 2006;Vineeth et al, 2007]. The most prominent manifestations of this day-to-day variability of EEJ are the time at which the EEJ peaks: its strength and the duration.…”

Section: Introductionmentioning

confidence: 99%

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Planetary wave-tidal interactions over the equatorial mesosphere-lower thermosphere region and their possible implications for the equatorial electrojet

et al. 2011

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[1] Optically measured daylight mean mesopause temperatures over a dip equatorial station, Trivandrum (8.5°N; 77°E; dip lat. 0.5°N), have been analyzed in conjunction with simultaneously measured equatorial electrojet (EEJ)-produced magnetic field at the surface. The signature of planetary wave-tidal interactions in the mesosphere-lower thermosphere (MLT) region has been observed for the first time in the day-to-day variability in the EEJ, i.e., the time of its peaking and the duration, as inferred from the EEJ-produced magnetic field on the ground. The present study shows that the planetary wave of quasi 16 day periodicity plays an important role in causing these variabilities, especially during the winter months. The quasi 16 day wave is found to be modulating the mesopause temperature (MT), duration, and time of the maximum EEJ intensity (D EEJ and T EEJ ). During positive excursions of the planetary wave, T EEJ showed a shift toward evening, while the MT showed an increase and D EEJ showed a broadening. Similarly, all these parameters exhibited an opposite trend during negative excursions. The planetary wave-tidal interactions and subsequent modification of the tidal components have been shown to be responsible for the observed variations. This study presents a new perspective addressing the day-to-day variability of the EEJ.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Planetary wave-tidal interactions over the equatorial mesosphere-lower thermosphere region and their possible implications for the equatorial electrojet

et al. 2011

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“…Recent investigations of quiet time atmosphere/ionosphere have revealed that the modulation in the lower atmospheric forcing is one of the major contributors to the ionospheric variability (Abdu et al, 2006;Vineeth et al, 2007a;Pedatella et al, 2008). The same has been found to be true even during specific transient events like the Sudden Stratospheric Warming (SSW).…”

Section: Introductionmentioning

confidence: 95%

A new insight into the vertical neutral-ion coupling between the mesopause and equatorial ionosphere F-region

et al. 2011

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Abstract. This letter reports unique observations, illustrating the vertical coupling between the daytime mesopause and F-region of the ionosphere over the magnetic dip equatorial station Trivandrum (8.5 • N, 76.5 • E, 0.5 • N dip lat.) in India. For the "first time", it has been shown that the temporal variations in the mean daytime mesopause temperatures (MPT), during geomagnetically quiet days corroborate well with that of the base height changes (h F ) of the ionospheric F-region. However, there exist some characteristic time delays between these two, which vary from 0 to 90 min. The MPTs are measured using the unique Multi-Wavelength Dayglow Photometer while the h F s are derived using a co-located digital Ionosonde. The observed time delays are attributed to the intercompeting roles between the diffusion and wavedynamical processes in modulating the transport of atomic oxygen at these altitudes.

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Quiet time short‐period and day‐to‐day variations in E × B drift studied using 150 km radar echoes from Gadanki

2014

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In this paper we present short-period and day-to-day variations in E × B drift during low solar and magnetically quiet conditions, based on radar observations of daytime 150 km echoes from Gadanki, India. Short-period (<100 min) variations in E × B drift show amplitude as large as 7 m s À1 and display large day-to-day variation. Spectral analysis reveals that drift velocity fluctuations consist of several components of short periods in the range of 4-100 min. Among these periods, the most frequently occurring periods are 6-60 min. Observations also show that amplitudes of these periods increase with increasing period. Interestingly, signal-to-noise ratio (SNR) variations also show periods of 3-19 min, which have also been observed in velocity variations. In addition, amplitudes of the periodic variations in SNR tend to increase with increasing period, which is also similar to those observed in drift velocity fluctuations. No correlation between SNR and velocity variations, however, has been found. Noticeable day-to-day variations in drift velocity are found in all seasons, and the variation is as large as ±25 m s À1 . Day-to-day variations also show wave-like features with period of 2-4 days. Observed E × B drift variations of 7 m s À1 at short time scale and 25 m s À1 on a day-to-day basis indicate zonal electric field variations of 0.25 mV/m and 0.9 mV/m, respectively. We surmise that quiet time E × B drift variations with periods <100 min and 2-4 days are likely to be the manifestations of gravity wave and planetary wave wind-induced electric fields, respectively, consistent with those reported earlier.

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Planetary wave signatures in the equatorial atmosphere–ionosphere system, and mesosphere- E- and F-region coupling

Cited by 80 publications

References 39 publications

Planetary wave-tidal interactions over the equatorial mesosphere-lower thermosphere region and their possible implications for the equatorial electrojet

Planetary wave-tidal interactions over the equatorial mesosphere-lower thermosphere region and their possible implications for the equatorial electrojet

A new insight into the vertical neutral-ion coupling between the mesopause and equatorial ionosphere F-region

Quiet time short‐period and day‐to‐day variations in E × B drift studied using 150 km radar echoes from Gadanki

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