Height and critical frequency variations of the sporadic-E layer at midlatitudes

Šauli, P.; Bourdillon, Alain

doi:10.1016/j.jastp.2008.03.016

Cited by 25 publications

(19 citation statements)

References 27 publications

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“…In spite of the other regular ionospheric layers, the E s cannot be explained via Chapman theory. The apparent chaos in occurring of the E s layers, confirms that complex mechanisms control the behavior of these layers [Šauli and Bourdillon, 2008].…”

Section: Introductionmentioning

confidence: 76%

“…However, infrared energy ( λ > 700 nm) absorption by water vapor in the troposphere is the key cause of tidal waves [ Brasseur and Solomon , 2005]. The effects of tides coming from below are playing major role in the process of ion convergence in the ionospheric E layer [ Šauli and Bourdillon , 2008]. In the present work, we focus on planetary and tidal waves.…”

Section: Introductionmentioning

confidence: 99%

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Planetary and tidal wave‐type oscillations in the ionospheric sporadic E layers over Tehran region

et al. 2012

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[1] It is believed that in the lower ionosphere, particularly in the ionospheric sporadic E (E s ) layers (90-130 km), the planetary and tidal wave-type oscillations in the ionized component indicate the planetary and tidal waves in the neutral atmosphere. In the present work, the presence of wave-type oscillations, including planetary and tidal waves in the ionospheric sporadic E layers over Tehran region is examined. Data measured by a digital ionosonde at the ionospheric station of the Institute of Geophysics, University of Tehran, from July 2006 to June 2007 are used to investigate seasonal variations of planetary and tidal waves activities. For the purpose of accurate comparison between different seasons, wavelet transform is applied to time series of foE s and h′E s , namely, the critical frequency and virtual height of E s layers, respectively. The results show that the sporadic E layers over Tehran region are strongly under the influence of upward propagation of waves from below. More specifically, among diverse range of periodicities in the sporadic E layers, we found that diurnal (24 hours) and semidiurnal (12 hours) oscillations in all seasons for both parameters. Moreover, terdiurnal (8 hours) tide-like variation is observed during spring and summer for foE s parameter and summer and winter for h′E s . Furthermore, the results show that diurnal tidal waves obtain their maximum activities during autumn and winter seasons, and their activities decrease during the late spring and summer. In addition, periods of about 2, 4, 6, 10, 14, and 16 days in our observation verifies the hypothesis of upward propagation of planetary waves from lower atmosphere to the ionosphere. Moreover, planetary waves have their maximum activities during equinox.

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Section: Introductionmentioning

confidence: 76%

Section: Introductionmentioning

confidence: 99%

Planetary and tidal wave‐type oscillations in the ionospheric sporadic E layers over Tehran region

et al. 2012

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“…Appearance of the inhomogeneous neutral wind could be related to various dynamical processes in the lower thermosphere, however the tidal motion is one of the most important one (Haldoupis et al, 2006;Pignalberi et al, 2014). Atmospheric waves, such as planetary waves (Shalimov et al, 1999;Haldoupis and Pancheva, 2002;Sauli and Bourdillon, 2008;Pignalberi et al, 2015), gravity waves, and the vortical perturbations of similar spatial scales (Didebulidze and Lomidze, 2008; could also lead to the Es formation. Shalimov et al (1999) and Shalimov and Haldoupis (2002) showed the possibility of E region plasma convergence inside a planetary wave cyclonic vortex at mid-latitudes.…”

Section: Introductionmentioning

confidence: 99%

Formation of sporadic-E (Es) layers under the influence of AGWs evolving in a horizontal shear flow

Didebulidze

Dalakishvili

Lomidze

et al. 2015

Journal of Atmospheric and Solar-Terrestrial Physics

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“…Experimental studies show that the development of these processes leads to ionospheric disturbances. For example, storms and hurricanes are accompanied by strong disturbances of ionospheric F2-layer parameters and total electron content (TEC) [Martinis, Manzano, 1999;Zakharov, Kunitsyn, 2012;Polyakova, Perevalova, 2013;Chernigovskaya et al, 2014Chernigovskaya et al, , 2015Koucká Knížová et al, 2015;Bogdanov et al, 2016;Karpov et al, 2016Karpov et al, , 2019.…”

Section: Introductionmentioning

confidence: 99%

Impact of Meteorological Storms on the E-Region of the Ionosphere in 2017–2018

Borchevkina

Карпов

et al. 2020

Solar-Terrestrial Physics

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The paper presents the results of observations of the sporadic Es layer during the period of meteorological disturbances in Kaliningrad in October 2017 and 2018 under quiet geomagnetic conditions. During the meteorological storms (October 29–30, 2017 and October 23–24, 2018), significant changes occurred in the dynamics of the Es-layer critical frequency. Observations of atmospheric and ionospheric disturbances in the Kaliningrad region show that the delay between the ionospheric response and the moment of maximum disturbances in atmospheric parameters is about 3 hours. These phenomena at the heights of the E-region might have been caused by propagation of acoustic-gravity waves generated by convective processes in the lower atmosphere during periods of a meteorological storm. Intensification of turbulent processes in the lower thermosphere leads to an increase in the atmospheric density and, accordingly, to higher recombination rates. This leads to a rapid decrease in the concentration of ions and, consequently, to a decrease in the critical frequency of the sporadic layer below the sensitivity threshold of ionosondes.

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Height and critical frequency variations of the sporadic-E layer at midlatitudes

Cited by 25 publications

References 27 publications

Planetary and tidal wave‐type oscillations in the ionospheric sporadic E layers over Tehran region

Planetary and tidal wave‐type oscillations in the ionospheric sporadic E layers over Tehran region

Formation of sporadic-E (Es) layers under the influence of AGWs evolving in a horizontal shear flow

Impact of Meteorological Storms on the E-Region of the Ionosphere in 2017–2018

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