Sporadic E Layer with a Structure of Double Cusp in the Vertical Sounding Ionogram

In this study, we analyzed a large number of vertical sounding ionograms, obtained by the mid-latitude Cyclone ionosonde (55.85° N; 48.8° E) of Kazan (Volga Region) Federal University, which operates in a rapid-run mode of ionograms (1 ionogram per minute). Ionograms with a sporadic E layer type c, which have an unusual double cusp on the trace from the sporadic layer, were found among them. We attempted to simulate this unusual double cusp trace shape. Model calculations were performed to clarify the reasons for the appearance of the double cusp and to determine the shape of the lower part of the E and Es layers. The simulation was performed by fitting the profile of the electron densities of the E and Es layers, calculating the virtual reflection heights based on the refractive index using the Appleton-Hartree formula, and comparing them with the virtual heights of the layers on the ionogram. An estimate of the half-thickness of the lower part of the Es-layer was obtained. The possible reasons for the appearance of a trace with a double cusp of the Es layer are discussed. We assumed that the possible reasons for this phenomenon were the stratification of the E layer, and the interaction between the E and F layers in the form of descending or intermediate layers and atmospheric wave propagation. As an illustration of these phenomena, examples of an intermediate (descending) sporadic E layer and stratification of the E region and the Es layer are given according to observations of the lower ionosphere. These examples were obtained through the resonant scattering of probe radio waves by artificial periodic irregularities (API technique) of the ionospheric plasma, performed on the SURA mid-latitude heating facility (56.1° N; 46.1° E). The scattering of probe radio waves on the APIs generated by the heating facility made it possible to study various phenomena in the Earth’s ionosphere.

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Results of studying the sporadic E layer by the method of resonant scattering of radio waves by artificial periodic inhomogeneities of the ionospheric plasma

Radiophysics and Quantum Electronics ◽

10.1007/s11141-009-9092-4 ◽

2008 ◽

Vol 51 (11) ◽

pp. 862-873 ◽

Cited By ~ 8

Author(s):

N. V. Bakhmet’eva ◽

V. V. Belikovich

Keyword(s):

Ionospheric Plasma ◽

Resonant Scattering ◽

Radio Waves ◽

Sporadic E Layer ◽

Sporadic E ◽

Periodic Inhomogeneities

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Equatorial E Region Electric Fields and Sporadic E Layer Responses to the Recovery Phase of the November 2004 Geomagnetic Storm

Journal of Geophysical Research Space Physics ◽

10.1002/2017ja024734 ◽

2017 ◽

Vol 122 (12) ◽

pp. 12,517-12,533 ◽

Cited By ~ 3

Author(s):

J. Moro ◽

L. C. A. Resende ◽

C. M. Denardini ◽

J. Xu ◽

I. S. Batista ◽

...

Keyword(s):

Geomagnetic Storm ◽

Electric Fields ◽

Recovery Phase ◽

E Region ◽

Sporadic E Layer ◽

Sporadic E

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Survey of electron density changes in the daytime ionosphere over the Arecibo observatory due to lightning and solar flares

Scientific Reports ◽

10.1038/s41598-021-89662-x ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Caitano L. da Silva ◽

Sophia D. Salazar ◽

Christiano G. M. Brum ◽

Pedrina Terra

Keyword(s):

Electron Density ◽

Solar Flares ◽

Low Frequency ◽

Lower Ionosphere ◽

Weather Conditions ◽

Optical Observations ◽

Radio Waves ◽

D Region ◽

E Region ◽

Arecibo Observatory

AbstractOptical observations of transient luminous events and remote-sensing of the lower ionosphere with low-frequency radio waves have demonstrated that thunderstorms and lightning can have substantial impacts in the nighttime ionospheric D region. However, it remains a challenge to quantify such effects in the daytime lower ionosphere. The wealth of electron density data acquired over the years by the Arecibo Observatory incoherent scatter radar (ISR) with high vertical spatial resolution (300-m in the present study), combined with its tropical location in a region of high lightning activity, indicate a potentially transformative pathway to address this issue. Through a systematic survey, we show that daytime sudden electron density changes registered by Arecibo’s ISR during thunderstorm times are on average different than the ones happening during fair weather conditions (driven by other external factors). These changes typically correspond to electron density depletions in the D and E region. The survey also shows that these disturbances are different than the ones associated with solar flares, which tend to have longer duration and most often correspond to an increase in the local electron density content.

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Energetics and structure of the lower E region associated with sporadic E layer

Annales Geophysicae ◽

10.5194/angeo-26-2929-2008 ◽

2008 ◽

Vol 26 (9) ◽

pp. 2929-2936 ◽

Cited By ~ 1

Author(s):

K.-I. Oyama ◽

K. Hibino ◽

T. Abe ◽

R. Pfaff ◽

T. Yokoyama ◽

...

Keyword(s):

Electric Field ◽

Field Data ◽

Magnetic Line ◽

Height Range ◽

Sounding Rockets ◽

Main Structure ◽

Irregular Structures ◽

E Region ◽

Sporadic E Layer ◽

Sporadic E

Abstract. The electron temperature (Te), electron density (Ne), and two components of the electric field were measured from the height of 90 km to 150 km by one of the sounding rockets launched during the SEEK-2 campaign. The rocket went through sporadic E layer (Es) at the height of 102 km–109 km during ascent and 99 km–108 km during decent, respectively. The energy density of thermal electrons calculated from Ne and Te shows the broad maximum in the height range of 100–110 km, and it decreases towards the lower and higher altitudes, which implies that a heat source exists in the height region of 100 km–110 km. A 3-D picture of Es, that was drawn by using Te, Ne, and the electric field data, corresponded to the computer simulation; the main structure of Es is projected to a higher altitude along the magnetic line of force, thus producing irregular structures of Te, Ne and electric field in higher altitude.

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Sporadic-E associated with the Leonid meteor shower event of November 1998 over low and equatorial latitudes

Annales Geophysicae ◽

10.5194/angeo-19-59-2001 ◽

2001 ◽

Vol 19 (1) ◽

pp. 59-69 ◽

Cited By ~ 10

Author(s):

H. Chandra ◽

S. Sharma ◽

C. V. Devasia ◽

K. S. V. Subbarao ◽

R. Sridharan ◽

...

Keyword(s):

Meteor Shower ◽

Low Latitude ◽

Equatorial Station ◽

Radio Science ◽

Ionospheric Physics ◽

Transmitter Power ◽

Multiple Structures ◽

E Region ◽

Sporadic E Layer ◽

Sporadic E

Abstract. Rapid radio soundings were made over Ahmedabad, a low latitude station during the period 16–20 November 1998 to study the sporadic-E layer associated with the Leonid shower activity using the KEL Aerospace digital ionosonde. Hourly ionograms for the period 11 November to 24 November were also examined during the years from 1994 to 1998. A distinct increase in sporadic-E layer occurrence is noticed on 17, 18 and 19 November from 1996 to 1998. The diurnal variations of f0Es and fbEs also show significantly enhanced values for the morning hours of 18 and 19 November 1998. The ionograms clearly show strong sporadic-E reflections at times of peak shower activity with multiple traces in the altitude range of 100–140 km in few ionograms. Sporadic-E layers with multiple structures in altitude are also seen in some of the ionograms (quarter hourly) at Thumba, situated near the magnetic equator. Few of ionograms recorded at Kodaikanal, another equatorial station, also show sporadic- E reflections in spite of the transmitter power being significantly lower. These new results highlighting the effect of intense meteor showers in the equatorial and low latitude E-region are presented.Key words. Ionosphere (equatorial ionosphere) – Radio science (ionospheric physics)

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Investigations of Atmospheric Waves in the Earth Lower Ionosphere by Means of the Method of the Creation of the Artificial Periodic Irregularities of the Ionospheric Plasma

Atmosphere ◽

10.3390/atmos10080450 ◽

2019 ◽

Vol 10 (8) ◽

pp. 450 ◽

Cited By ~ 1

Author(s):

Nataliya V. Bakhmetieva ◽

Gennady I. Grigoriev ◽

Ariadna V. Tolmacheva ◽

Ilia N. Zhemyakov

Keyword(s):

Lower Ionosphere ◽

Resonant Scattering ◽

Internal Gravity Waves ◽

Neutral Atmosphere ◽

Neutral Component ◽

Plasma Velocity ◽

Radio Waves ◽

Atmospheric Waves ◽

Ionosphere Plasma ◽

Powerful High Frequency

We present results of the studies of internal gravity waves based on altitude-time dependences of the temperature and the density of the neutral component and the velocity of the vertical plasma motion at altitudes of the lower ionosphere (60–130 km). The vertical plasma velocity, which in the specified altitude range is equal to the velocity of the neutral component, the temperature, and the density of the neutral atmosphere are determined by the method of the resonant scattering of radio waves by artificial periodic irregularities (APIs) of the ionosphere plasma. We have developed an API technique and now we are evolving it for studying the ionosphere and the neutral atmosphere using the Sura heating facility (56.1 N; 46.1 E), Nizhny Novgorod, Russia. An advantage of the API technique is the opportunity to determine the parameters of the undisturbed natural environment under a disturbance of the ionosphere by a field of powerful high frequency radio waves. Analysis of altitude-time variations of the neutral temperature, the density, and the vertical plasma velocity allows one to estimate periods of atmospheric waves propagation. Wavelike variations with a period from 5 min to 3 h and more are clearly determined.

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Artificial periodic irregularities, wave phenomena in the lower ionosphere, and the sporadic E layer

Radiophysics and Quantum Electronics ◽

10.1007/s11141-010-9210-3 ◽

2010 ◽

Vol 53 (2) ◽

pp. 69-81 ◽

Cited By ~ 10

Author(s):

N. V. Bakhmet’eva ◽

V. V. Belikovich ◽

M. N. Egereva ◽

A. V. Tolmacheva

Keyword(s):

Lower Ionosphere ◽

Sporadic E Layer ◽

Sporadic E ◽

Wave Phenomena

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Mid Latitude Sporadic E-layer Variability during Ascending Phase of Solar Cycle 24

Journal of Scientific Research ◽

10.3329/jsr.v1i1.28749 ◽

2017 ◽

Vol 9 (1) ◽

pp. 27-41

Author(s):

R. Atulkar ◽

P. A. Khan ◽

A. A. Mansoori ◽

P. K. Purohit

Keyword(s):

Solar Cycle ◽

Summer Season ◽

High Solar Activity ◽

Night Time ◽

Solar Cycle 24 ◽

E Region ◽

Sporadic E Layer ◽

Sporadic E ◽

Cycle 24 ◽

Short Time

The paper presents a comparative study of the ionospheric sporadic E layer parameters (fbEs, foEs, and hEs) retrieved from ground based ionosonde at mid latitude station Yamagawa, Japan (31.20 N, 130.370 E) during the ascending phase of 24th solar cycle i.e. during January 2012 to December 2014. The comparison between the E-region parameters has been carried out on a diurnal, seasonal, annual and day night basis. The diurnal maxima of foEs, fbEs, and hEs are generally higher during high solar activity. From the present study it is found that the highest values of fbEs are observed during the summer while the lowest values are observed during autumn at mid latitude. Similarly, the highest values of foEs are observed during the summer season while the lowest values are recorded in autumn season. However, the highest values of hEs are recorded during the spring and the lowest values are recorded in autumn. The variability of Es during the day and night time is also studied. The sporadic E can form and disappear in a short time during either the day or night. We have also studied the percentage occurrence of sporadic E. The occurrence of Es changes from year to year.

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First simulations of day-to-day variability of mid-latitude sporadic E layer structures

Earth Planets and Space ◽

10.1186/s40623-020-01299-8 ◽

2020 ◽

Vol 72 (1) ◽

Author(s):

Satoshi Andoh ◽

Akinori Saito ◽

Hiroyuki Shinagawa ◽

Mitsumu K. Ejiri

Keyword(s):

Three Dimensional ◽

Lower Ionosphere ◽

Atmospheric Tides ◽

Ionospheric Model ◽

Radio Waves ◽

Metallic Ions ◽

Long Distance ◽

Distance Communication ◽

Sporadic E ◽

Realistic Information

Abstract We present the first simulations that successfully reproduce the day-to-day variability of the mid-latitude sporadic E ($$E_s$$ E s ) layers. $$E_s$$ E s layers appearing in the lower ionosphere have been extensively investigated to monitor and forecast their effects on long-distance communication by radio waves. Although it is widely accepted that the atmospheric tides are important in generating the $$E_s$$ E s layers, no simulations to date have reproduced the $$E_s$$ E s layers observed on a certain day. This is due to the lack of the combination of realistic information on the atmospheric tides in the lower ionosphere and a three-dimensional numerical ionospheric model that can simulate the precise transport of metallic ions. We developed a numerical ionospheric model coupled with the neutral winds from the GAIA (Ground-to-topside model of Atmosphere and Ionosphere for Aeronomy). The fundamental structures and the day-to-day variations of the $$E_s$$ E s layers observed by a $$\hbox {Ca}^+$$ Ca + lidar are well-reproduced in the simulations.

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