scholarly journals 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 ◽  
2019 ◽  
Vol 10 (8) ◽  
pp. 450 ◽  
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.

scholarly journals Perspective Ground-based Method for Diagnostics of the Lower Ionosphere and the Neutral Atmosphere

2013 ◽  
Vol 22 (1) ◽  
Author(s):  
N. V. Bakhmetieva ◽  
G. I. Grigoriev ◽  
A. V. Tolmacheva
Keyword(s):  
Radio Wave ◽  
High Power ◽  
Relative Concentration ◽  
Spectral Characteristics ◽  
Lower Ionosphere ◽  
Internal Gravity Waves ◽  
Spatial Period ◽  
Neutral Atmosphere ◽  
Radio Waves ◽  
D Region

AbstractWe present a new perspective ground-based method for diagnostics of the ionosphere and atmosphere parameters. The method uses one of the numerous physical phenomena observed in the ionosphere illuminated by high-power radio waves. It is a generation of the artificial periodic irregularities (APIs) in the ionospheric plasma. The APIs were found while studying the effects of ionospheric high-power HF modification. It was established that the APIs are formed by a standing wave that occurs due to interference between the upwardly radiated radio wave and its reflection off the ionosphere. The API studies are based upon observation of the Bragg backscatter of the pulsed probe radio wave from the artificial periodic structure. Bragg backscatter occurs if the spatial period of the irregularities is equal to half a wavelength of the probe signal. The API techniques makes it possible to obtain the following information: the profiles of electron density from the lower D-region up to the maximum of the F-layer; the irregular structure of the ionosphere including split of the regular E-layer, the sporadic layers; the vertical velocities in the D- and E-regions of the ionosphere; the turbulent velocities, turbulent diffusion coefficients and the turbopause altitude; the neutral temperatures and densities at the E-region altitudes; the parameters of the internal gravity waves and their spectral characteristics; the relative concentration of negative oxygen ions in the D-region. Some new results obtained by the API technique are discussed.

scholarly journals On the Diagnosis of Unidirectional Acoustic Waves as Applied to the Measurement of Atmospheric Parameters by the API Method in the SURA Experiment

Atmosphere ◽  
2020 ◽  
Vol 11 (9) ◽  
pp. 924
Author(s):  
Sergey Leble ◽  
Sergey Vereshchagin ◽  
Nataliya V. Bakhmetieva ◽  
Gennadiy I. Grigoriev
Keyword(s):  
Acoustic Waves ◽  
Wave Theory ◽  
Resonant Scattering ◽  
Projection Operators ◽  
Evolution System ◽  
Neutral Atmosphere ◽  
Radio Waves ◽  
Reflected Waves ◽  
Density Perturbations ◽  
Wave Identification

The problem of wave identification is formulated as applied to the results of measurements of the temperature and the density of the neutral atmosphere in the range height 90–120 km by the artificial periodic irregularities (APIs) technique. The technique is based on the resonant scattering of radio waves by artificial periodic irregularities of the ionospheric plasma emerging in the field of a standing wave arising from the interference of the incident and reflected waves from the ionosphere. APIs were created using SURA heating facility (named as SURA experiment). The acoustic wave theory is reformulated on the base of data which can be observed in the given experimental setup. The basic system of equations is reduced so that it accounts only upward and downward directed waves, ignoring entropy mode. The algorithm of wave identification based on usage of dynamic projection operators for such a reduced case is proposed and explicit form of projection operators is derived. Its application to finite number dataset via Discrete Fourier Transform (DFT) is described and results of its application to the DFT-transformed set of experimental observation of the temperature and density perturbations are presented. The result yields hybrid amplitudes, that allow us to calculate energy of the directed waves that enter the observed superposition. The problem of entropy mode detection is discussed, the corresponding projecting operators for the full evolution system are built and a way to apply the method to quantification of it is proposed.

Numerical modelling of coupled neutral atmospheric general circulation and ionosphere D region

2016 ◽  
Vol 31 (3) ◽  
Author(s):  
Dmitry V Kulyamin ◽  
Valentin P. Dymnikov
Keyword(s):  
General Circulation ◽  
Coupled Model ◽  
Lower Ionosphere ◽  
Circulation Model ◽  
Neutral Atmosphere ◽  
Radio Waves ◽  
Signal Attenuation ◽  
Differential Formulation ◽  
D Region ◽  
Radio Signals

AbstractThe paper presents a new neutral atmosphere and ionosphere D region coupled general circulation model (for altitudes of 0-90 km) with a high spatial resolution. Efficient numerical methods of its implementation are developed. The properties of differential formulation for a plasma-chemical model of ionosphere D region are studied, the existence of a global attractor in the non-negative half of the phase space is proved, an efficient semi-implicit numerical scheme possessing the charge conservation law is constructed to solve the system. The problem of radio waves propagation in the ionosphere D region has been considered for the coupled model, we validated the model on the base of radio signals monitoring data and developed a computational unit for calculation of the radio signal attenuation in the lower ionosphere. A satisfactory reproduction of the D region mean state is shown and the ability to develope this model for use in applied tasks is indicated.

scholarly journals Study of a Gas Disturbance Mode Content Based on the Measurement of Atmospheric Parameters at the Heights of the Mesosphere and Lower Thermosphere

Atmosphere ◽  
2021 ◽  
Vol 12 (9) ◽  
pp. 1123
Author(s):  
Sergey Leble ◽  
Sergey Vereshchagin ◽  
Nataliya V. Bakhmetieva ◽  
Gennadiy I. Grigoriev
Keyword(s):  
Lower Thermosphere ◽  
Resonant Scattering ◽  
Projection Operators ◽  
Neutral Atmosphere ◽  
Radio Waves ◽  
Heating Facility ◽  
Mode Content ◽  
Mode Separation ◽  
Mesosphere And Lower Thermosphere ◽  
Dynamic Variables

The main result of this work is the estimation of the entropy mode accompanying a wave disturbance, observed at the atmosphere heights range of 90–120 km. The study is the direct continuation and development of recent results on diagnosis of the acoustic wave with the separation on direction of propagation. The estimation of the entropy mode contribution relies upon the measurements of the three dynamic variables (the temperature, density, and vertical velocity perturbations) of the neutral atmosphere measured by the method of the resonant scattering of radio waves on the artificial periodic irregularities of the ionospheric plasma. The measurement of the atmosphere dynamic parameters was carried out on the SURA heating facility. The mathematical foundation of the mode separation algorithm is based on the dynamic projection operators technique. The operators are constructed via the eigenvectors of the coordinate evolution operator of the transformed system of balance equations of the hydro-thermodynamics.

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

Atmosphere ◽  
2021 ◽  
Vol 12 (9) ◽  
pp. 1093
Author(s):  
Kamil M. Yusupov ◽  
Nataliya V. Bakhmetieva
Keyword(s):  
Lower Ionosphere ◽  
Resonant Scattering ◽  
Radio Waves ◽  
Model Calculations ◽  
Heating Facility ◽  
Intermediate Layers ◽  
E Region ◽  
Type C ◽  
Sporadic E Layer ◽  
Sporadic E

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.

Changing ionization of the lower ionosphere due to high-power radio waves

1977 ◽  
Vol 20 (12) ◽  
pp. 1230-1239 ◽  
Author(s):  
A. V. Gurevich ◽  
G. M. Milikh ◽  
I. S. Shlyuger
Keyword(s):  
High Power ◽  
Lower Ionosphere ◽  
Radio Waves

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

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.

scholarly journals Internal Gravity Waves in a Saturated Moist Neutral Atmosphere

2013 ◽  
Vol 70 (12) ◽  
pp. 3693-3709 ◽  
Author(s):  
David J. Muraki ◽  
Richard Rotunno
Keyword(s):  
Numerical Solutions ◽  
Internal Gravity Waves ◽  
Analytic Solutions ◽  
Neutral Atmosphere ◽  
Atmospheric Flow ◽  
Start Up ◽  
Exact Analytic Solutions ◽  
Downward Displacement ◽  
Neutral Flow ◽  
Saturated Atmosphere

Abstract This work is motivated by an unusual feature associated with the start-up of a moist nearly neutral atmospheric flow over a mountain ridge that was previously observed in a full-physics numerical model. In that study, the upstream propagation of a wave of subsidence precluded the establishment of upward-displaced and saturated flow that might be expected upstream of the topography. This phenomenon was hypothesized to be a consequence of the peculiar property of saturated moist neutral flow: an upward air parcel displacement produces zero buoyancy, while a downward displacement desaturates the air parcel and produces a positive buoyancy anomaly. In the present study, this hypothesis is confirmed within numerical solutions to a reduced system of equations that incorporates the saturated-atmosphere property in a particularly simple manner. The relatively uncomplicated nature of these solutions motivates the numerical solution of a further simplified initial-value problem for both nonhydrostatic and hydrostatic flow. Exact analytic solutions are developed for the latter hydrostatic case, which explains the upstream-propagating wave of subsidence as a shock phenomenon.

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