Influence of electronic emissions on the state of the lower ionosphere and amplitude characteristics of VLF radio signals

2021 ◽  
Author(s):  
Karina Babaykina ◽  
Boris Gavrilov ◽  
Yuriy Poklad
Keyword(s):  
Lower Ionosphere ◽  
The State ◽  
Radio Signals ◽  
Amplitude Characteristics

On the characterization of VLF radio signal propagation in atmosphere in quite solar conditions

2020 ◽  
Author(s):  
Giovanni Nico ◽  
Aleksandra Nina ◽  
Anita Ermini ◽  
Pierfrancesco Biagi
Keyword(s):  
Radio Signal ◽  
Technological Development ◽  
Low Frequency ◽  
Lower Ionosphere ◽  
Signal Propagation ◽  
Temporal Variations ◽  
Seasonal Effects ◽  
Propagation Mode ◽  
Theory Approach ◽  
Radio Signals

<p>In this work we use Very Low Frequency (VLF) radio signals, having a frequency in the bands 20-80 kHz, to study the VLF signal propagation in the atmosphere quite undisturbed conditions by selecting the signals recorded during night. As a good approximation, we can model the propagation of VLF radio signals as characterized by a ground-wave and a sky-wave propagation mode. The first one generates a radio signal that propagates in the channel ground-troposphere, while the second one generates a signal which propagates using the lower ionosphere as a reflector. The VLF receivers of the INFREP (European Network of Electromagnetic Radiation) network are used. These receivers have been installed since 2009 mainly in southern and central Europe and currently the INFREP network consists of 9 receivers. A 1-minute sampling interval is used to record the amplitude of VLF signals. Long time-series of VLF signals propagating during night are extracted from recorded signals to study possible seasonal effects due to temporal variations in the physical properties of troposphere. A graph theory approach is used to investigate the spatial correlation of the aforementioned effects at different receivers. A multivariate analysis is also applied to identify common temporal changes observed at VLF receivers.</p><p>This work was supported by the Ministero dell'Istruzione, dell'Università e della Ricerca (MIUR), Italy, under the project OT4CLIMA. This research is supported by the Ministry of Education, Science and Technological Development of the Republic of Serbia, under the projects 176002 and III44002.</p>

scholarly journals Characterization of gravity waves in the lower ionosphere using very low frequency observations at Comandante Ferraz Brazilian Antarctic Station

2020 ◽  
Vol 38 (2) ◽  
pp. 385-394
Author(s):  
Emilia Correia ◽  
Luis Tiago Medeiros Raunheitte ◽  
José Valentin Bageston ◽  
Dino Enrico D'Amico
Keyword(s):  
Low Frequency ◽  
Lower Ionosphere ◽  
Drake Passage ◽  
Wave Period ◽  
Very Low Frequency ◽  
Reflection Height ◽  
D Region ◽  
Radio Signals ◽  
Sky Conditions ◽  
The Waves

Abstract. The goal of this work is to investigate the gravity wave (GW) characteristics in the low ionosphere using very low frequency (VLF) radio signals. The spatial modulations produced by the GWs affect the conditions of the electron density at reflection height of the VLF signals, which produce fluctuations of the electrical conductivity in the D region that can be detected as variations in the amplitude and phase of VLF narrowband signals. The analysis considered the VLF signal transmitted from the US Cutler, Maine (NAA) station that was received at Comandante Ferraz Brazilian Antarctic Station (EACF, 62.1∘ S, 58.4∘ W), with its great circle path crossing the Drake Passage longitudinally. The wave periods of the GWs detected in the low ionosphere are obtained using the wavelet analysis applied to the VLF amplitude. Here the VLF technique was used as a new aspect for monitoring GW activity. It was validated comparing the wave period and duration properties of one GW event observed simultaneously with a co-located airglow all-sky imager both operating at EACF. The statistical analysis of the seasonal variation of the wave periods detected using VLF technique for 2007 showed that the GW events occurred all observed days, with the waves with a period between 5 and 10 min dominating during night hours from May to September, while during daytime hours the waves with a period between 0 and 5 min are predominant the whole year and dominate all days from November to April. These results show that VLF technique is a powerful tool to obtain the wave period and duration of GW events in the low ionosphere, with the advantage of being independent of sky conditions, and it can be used during the whole day and year-round.

scholarly journals 9. Some results of outer ionospheric studies based on radio observations of the first sputnik

1960 ◽  
Vol 10 ◽  
pp. 717-718
Author(s):  
Y. L. Alpert
Keyword(s):  
High Speed ◽  
Elliptic Integral ◽  
Theoretical Calculations ◽  
Outer Part ◽  
Lower Ionosphere ◽  
Horizontal Distance ◽  
Exponential Decline ◽  
Radio Signals ◽  
Electronic Concentration ◽  
Outer Ionosphere

AbstractThe method and results of the study of the outer ionosphere based on the ' rise' and ' set' of radio signals of the sputnik are given in full in the paper of which this is an abstract. Results of the theoretical calculations of the maximum horizontal distance rM of signalreception, which are needed for the treatment of experimental data, are also described. Calculations were carried out for a spherical Earth, and the resulting elliptic integral was tabulated by means of the high-speed electronic computer of the Academy of Sciences of the U.S.S.R. A parabolic model of the lower ionosphere and an exponential decline of electronic concentration in its outer part were accepted.

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.

Correlated Disturbances of the Upper and Lower Ionosphere from Synchronous Measurements of Parameters of GNSS Signals and VLF Radio Signals

2019 ◽  
Vol 57 (1) ◽  
pp. 36-43 ◽  
Author(s):  
B. G. Gavrilov ◽  
Yu. I. Zetser ◽  
A. N. Lyakhov ◽  
Yu. V. Poklad ◽  
I. A. Ryakhovskii
Keyword(s):  
Lower Ionosphere ◽  
Radio Signals

scholarly journals Ionospheric effects of earthquakes in Japan in March 2011 obtained from observations of lightning electromagnetic radio signals

2012 ◽  
Vol 12 (10) ◽  
pp. 3181-3190 ◽  
Author(s):  
V. A. Mullayarov ◽  
V. V. Argunov ◽  
L. M. Abzaletdinova ◽  
V. I. Kozlov
Keyword(s):  
Gravity Waves ◽  
Initial Period ◽  
Lower Ionosphere ◽  
Periodic Variation ◽  
Japanese Island ◽  
Strong Earthquakes ◽  
Radio Signals ◽  
Electromagnetic Signals ◽  
Earthquake Effects ◽  
Atmospheric Gravity

Abstract. Manifestations of disturbances in the lower ionosphere caused by a complex series of earthquakes (the strong earthquakes with M = 7.3 and M = 9 – known as M9 Tohoku EQ – and the subsequent aftershocks) that occurred near the Japanese island of Honshu have been considered with the use of monitoring measurements of the amplitude of lightning electromagnetic signals (atmospherics) received at Yakutsk. Some data of one-point lightning location systems have been compared with the data of the WWLLN network. The analysis of hourly values variation of the atmospheric amplitude passing over the earthquake epicenters shows that during the initial period (the strong earthquakes on 9 March and 11 March) a typical pattern of variations was observed. It was manifested in the increased amplitude after both earthquakes. There were also possible precursors in the form of the increase in amplitude 12–14 days before the events. Though the focuses of these earthquakes were very close to each other, the registration of both precursors may indicate that both of the lithospheric processes developed to a certain extent independently. During all the days of the atmospheric amplitude enhancement the quasi-periodic variation trains were recorded. Together with the delay of earthquake effects relative to the time of the events, they may testify in favor of transferring the energy of lithospheric processes into the lower ionosphere by means of atmospheric gravity waves.

Influence of the state of the sea surface upon the spatial characteristics of scattered radio signals

1966 ◽  
Vol 8 (6) ◽  
pp. 804-810 ◽  
Author(s):  
A. I. Kalmykov ◽  
I. E. Ostrovskii ◽  
A. D. Rozenberg ◽  
I. M. Fuchs
Keyword(s):  
The State ◽  
Sea Surface ◽  
Spatial Characteristics ◽  
Radio Signals

scholarly journals Characterization of gravity waves in the lower ionosphere using VLF observations at Comandante Ferraz Brazilian Antarctic Station

2019 ◽  
Author(s):  
Emilia Correia ◽  
Luis Tiago Medeiros Raunheitte ◽  
José Valentin Bageston ◽  
Dino Enrico D'Amico
Keyword(s):  
Gravity Waves ◽  
Low Frequency ◽  
Lower Ionosphere ◽  
Drake Passage ◽  
Wave Period ◽  
Reflection Height ◽  
D Region ◽  
Radio Signals ◽  
Almost All ◽  
Sky Conditions

Abstract. The goal of this work is to investigate the gravity waves (GWs) characteristics in the low ionosphere using very low frequency (VLF) radio signals. The spatial modulations produced by the GWs affect the conditions of the electron density at reflection height of the VLF signals, which produce fluctuations of the electrical conductivity in the D-region that can be detected as variations in the amplitude and phase of VLF narrowband signals. The analysis considered the VLF signal transmitted from the US Cutler/Marine (NAA) station that was received at Comandante Ferraz Brazilian Antarctic Station (EACF, 62.1° S, 58.4° W), which is a great circle path crossing longitudinally the Drake Passage. The wave periods of the GWs detected in the low ionosphere are obtained using the wavelet analysis applied to the VLF amplitude. The use of the VLF technique was validated comparing the wave period and duration properties of one GW event observed simultaneously with a co-located airglow all-sky imager both operating at EACF. The statistical analysis of the wave periods detected using VLF technique for 2007 showed that the GW events occur almost all nights, with a higher frequency per month from March to October. The predominant wave periods are more frequent between 10 and 15 min occurring preferentially during the equinoxes, but there are some events with periods higher than 60 min appearing only in the solstices (January and July). These results show that VLF technique is a powerful tool to obtain the wave period and duration of GW events in the low ionosphere, with the advantage to be independent of sky conditions, and can be used during daytime and year-round.

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