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  • 1
    Publication Date: 2020-12-03
    Description: A model is developed of the gradient drift instability growth rate in the north polar cap ionosphere, utilizing a novel approach employing an ionospheric imaging algorithm. The growth rate values calculated by this model are in turn used to estimate how the amplitudes of actual gradient drift waves vary over time as the plasma drifts and the growth rates change with time. Ionospheric imaging is again used in order to determine plasma drift velocities. The final output from the model is in turn used to assess the linear correlation between the scintillation indices S4 and σØ recorded by several GPS L1 band scintillation receivers stationed in the north polar cap and mean gradient drift wave amplitudes. Four separate magnetic storm periods, totaling 13 days, are analyzed in this way. The results show weak but significant linear correlations between the mean wave amplitudes calculated and the observed scintillation indices at F layer altitudes.
    Description: Published
    Description: A07309
    Description: 1.7. Osservazioni di alta e media atmosfera
    Description: 3.9. Fisica della magnetosfera, ionosfera e meteorologia spaziale
    Description: JCR Journal
    Description: reserved
    Keywords: scintillations ; polar ionosphere ; gradient drift ; instability ; 01. Atmosphere::01.02. Ionosphere::01.02.04. Plasma Physics ; 01. Atmosphere::01.02. Ionosphere::01.02.07. Scintillations ; 03. Hydrosphere::03.03. Physical::03.03.05. Instruments and techniques ; 05. General::05.07. Space and Planetary sciences::05.07.01. Solar-terrestrial interaction ; 05. General::05.07. Space and Planetary sciences::05.07.02. Space weather
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 2
    Publication Date: 2021-05-17
    Description: This paper presents a review of the ionospheric scintillation monitoring and modelling by the European groups involved in COST 296. Several of these groups have organized scintillation measurement campaigns at low and high latitudes. Some characteristic results obtained from the measured data are presented. The paper also addresses the modeling activities: four models, based on phase screen techniques, with different options and application domains are detailed. Finally some new trends for research topics are given. This includes the wavelet analysis, the high latitudes analysis, the construction of scintillation maps and the mitigation techniques.
    Description: Published
    Description: 391-416
    Description: 3.9. Fisica della magnetosfera, ionosfera e meteorologia spaziale
    Description: JCR Journal
    Description: open
    Keywords: scintillation ; measurement campaigns ; phase screen models ; radar ; wavelets ; maps ; 01. Atmosphere::01.02. Ionosphere::01.02.04. Plasma Physics ; 01. Atmosphere::01.02. Ionosphere::01.02.05. Wave propagation ; 01. Atmosphere::01.02. Ionosphere::01.02.07. Scintillations ; 01. Atmosphere::01.03. Magnetosphere::01.03.99. General or miscellaneous
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 3
    Publication Date: 2020-12-03
    Description: A model is presented of the growth rate of turbulently generated irregularities in the electron concentration of northern polar cap plasma patches. The turbulence is generated by the short‐term fluctuations in the electric field imposed on the polar cap ionosphere by electric field mapping from the magnetosphere. The model uses an ionospheric imaging algorithm to specify the state of the ionosphere throughout. The growth rates are used to estimate mean amplitudes for the irregularities, and these mean amplitudes are compared with observations of the scintillation indices S4 and s by calculating the linear correlation coefficients between them. The scintillation data are recorded by GPS L1 band receivers stationed at high northern latitudes. A total of 13 days are analyzed, covering four separate magnetic storm periods. These results are compared with those from a similar model of the gradient drift instability (GDI) growth rate. Overall, the results show better correlation between the GDI process and the scintillation indices than for the turbulence process and the scintillation indices. Two storms, however, show approximately equally good correlations for both processes, indicating that there might be times when the turbulence process of irregularity formation on plasma patches may be the controlling one.
    Description: Published
    Description: A04310
    Description: 1.7. Osservazioni di alta e media atmosfera
    Description: 3.9. Fisica della magnetosfera, ionosfera e meteorologia spaziale
    Description: JCR Journal
    Description: restricted
    Keywords: ionospheric irregularities ; scintillations ; Gradient Drift Instability ; 01. Atmosphere::01.02. Ionosphere::01.02.04. Plasma Physics ; 01. Atmosphere::01.02. Ionosphere::01.02.07. Scintillations ; 05. General::05.01. Computational geophysics::05.01.03. Inverse methods
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 4
    Publication Date: 2020-12-03
    Description: The global positioning system (GPS) phase scintillation caused by highlatitude ionospheric irregularities during an intense high-speed stream (HSS) of the solar wind from April 29 to May 5, 2011, was observed using arrays of GPS ionospheric scintillation and total electron content monitors in the Arctic and Antarctica. The one-minute phase-scintillation index derived from the data sampled at 50 Hz was complemented by a proxy index (delta phase rate) obtained from 1-Hz GPS data. The scintillation occurrence coincided with the aurora borealis and aurora australis observed by an all-sky imager at the South Pole, and by special sensor ultraviolet scanning imagers on board satellites of the Defense Meteorological Satellites Program. The South Pole (SP) station is approximately conjugate with two Canadian High Arctic Ionospheric Network stations on Baffin Island, Canada, which provided the opportunity to study magnetic conjugacy of scintillation with support of riometers and magnetometers. The GPS ionospheric pierce points were mapped at their actual or conjugate locations, along with the auroral emission over the South Pole, assuming an altitude of 120 km. As the aurora brightened and/or drifted across the field of view of the all-sky imager, sequences of scintillation events were observed that indicated conjugate auroras as a locator of simultaneous or delayed bipolar scintillation events. In spite of the greater scintillation intensity in the auroral oval, where phase scintillation sometimes exceeded 1 radian during the auroral break-up and substorms, the percentage occurrence of moderate scintillation was highest in the cusp. Interhemispheric comparisons of bipolar scintillation maps show that the scintillation occurrence is significantly higher in the southern cusp and polar cap.
    Description: Published
    Description: R0216
    Description: 1.7. Osservazioni di alta e media atmosfera
    Description: 3.9. Fisica della magnetosfera, ionosfera e meteorologia spaziale
    Description: JCR Journal
    Description: open
    Keywords: Scintillations ; Solar-terrestrial interaction ; Space weather ; Solar variability and solar wind ; Magnetic storms ; 01. Atmosphere::01.02. Ionosphere::01.02.99. General or miscellaneous ; 01. Atmosphere::01.02. Ionosphere::01.02.05. Wave propagation ; 01. Atmosphere::01.02. Ionosphere::01.02.06. Instruments and techniques ; 01. Atmosphere::01.02. Ionosphere::01.02.07. Scintillations ; 05. General::05.07. Space and Planetary sciences::05.07.02. Space weather
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 5
    Publication Date: 2021-05-17
    Description: Transionospheric radio signals may experience fluctuations in their amplitude and phase due to irregularity in the spatial electron density distribution, referred to as scintillation. Ionospheric scintillation is responsible for transionospheric signal degradation that can affect the performance of satellite based navigation systems. Usually, the scintillation activity is measured by means of indices such as the normalised standard deviation of the received intensity S4 and the standard deviation of the received phase r/ typically calculated over 1 min of data. Data from a GPS scintillation monitor based on 50 Hz measurements recorded at Dirigibile Italia Station (Ny-Alesund, Svalbard), in the frame of the ISACCO project (De Franceschi et al., 2006) are used to investigate possible adoption of an alternative parameter for the estimate of phase fluctuations: i.e., the standard deviation of the phase rate of change S/. This parameter is shown to better correlate with S4 being much less detrending dependent than r/. The couple (S4, S/) should be then considered a more physical proxy of radio scintillation than the couple (S4, r/).
    Description: Published
    Description: 2188–2193
    Description: 1.7. Osservazioni di alta e media atmosfera
    Description: 3.9. Fisica della magnetosfera, ionosfera e meteorologia spaziale
    Description: JCR Journal
    Description: restricted
    Keywords: Scintillation ; GPS monitors ; Auroral latitudes ; 01. Atmosphere::01.02. Ionosphere::01.02.04. Plasma Physics ; 01. Atmosphere::01.02. Ionosphere::01.02.07. Scintillations ; 05. General::05.01. Computational geophysics::05.01.03. Inverse methods
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 6
    Publication Date: 2021-06-16
    Description: Scintillations are rapid fluctuations in the phase and amplitude of transionospheric radio signals which are caused by small-scale plasma density irregularities in the ionosphere. In the case of the Global Navigation Satellite System (GNSS) receivers, scintillation can cause cycle slips, degrade the positioning accuracy and, when severe enough, can even lead to a complete loss of signal lock. Thus, the required levels of availability, accuracy, integrity and reliability for the GNSS applications may not be met during scintillation occurrence; this poses a major threat to a large number of modern-day GNSS-based applications. The whole of Latin America, Brazil in particular, is located in one of the regions most affected by scintillations. These effects will be exacerbated during solar maxima, the next predicted for 2013. This paper presents initial results from a research work aimed to tackle ionospheric scintillation effects for GNSS users in Latin America. This research is a part of the CIGALA (Concept for Ionospheric Scintillation Mitigation for Professional GNSS in Latin America) project, co-funded by the EC Seventh Framework Program and supervised by the GNSS Supervisory Authority (GSA), which aims to develop and test ionospheric scintillation countermeasures to be implemented in multi-frequency, multi-constellation GNSS receivers.
    Description: Published
    Description: A05
    Description: 3.9. Fisica della magnetosfera, ionosfera e meteorologia spaziale
    Description: N/A or not JCR
    Description: open
    Keywords: modelling and forecasting ; ionosphere ; equatorial ionosphere ; ionospheric irregularities ; 01. Atmosphere::01.02. Ionosphere::01.02.06. Instruments and techniques ; 01. Atmosphere::01.02. Ionosphere::01.02.07. Scintillations ; 05. General::05.04. Instrumentation and techniques of general interest::05.04.99. General or miscellaneous ; 05. General::05.08. Risk::05.08.01. Environmental risk
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 7
    Publication Date: 2021-06-07
    Description: To study ionospheric scintillation on L-band radio signals, it is nowadays typical to acquire data with GNSS (Global Navigation Satellite System) receivers working at high frequency sampling rate (50-100 Hz). When dealing with such data, it is common to consider the contribution coming solely from observations at elevation angles, calculated from the receiver to the selected satellite, above an arbitrary threshold, typically 15-30°. Filtering out measurements made at low elevation angles helps keeping a high SNR (Signal to Noise Ratio) and eliminating non-ionospheric related effects, such as multipath. The downside of that well consolidated method is a reduction of the field of view spanned by the GNSS receiver antenna, and, if it is the case, of the whole network. This is not crucial for dense networks or well covered areas, but it can be in the case of not well covered regions, for logistics (e.g. forests, deserts, etc.) and/or environmental reasons (e.g. oceans). The loss of information in many applications could be meaningful. In this paper, we present a method to filter out spurious data based on an “outliers analysis” able to efficiently remove multipath affected measurements, reducing the data loss from 35-45% to 10-20%. It is based upon the Ground Based Scintillation Climatology (GBSC) and the station characterization based upon GBSC [5] is applied to the CIGALA1/ CALIBRA2 network in Brazil. The research shown herein was carried out in the context of the CALIBRA (http://www.calibra-ionosphere.net) project and exploits the CIGALA/ CALIBRA network in Brazil, to which the method was applied, enlarging the field of view and, then, improving the capability of inferring the dynamics of the low latitude ionosphere.
    Description: Published
    Description: 109-117
    Description: 2A. Fisica dell'alta atmosfera
    Description: open
    Keywords: GNSS ; data filtering ; multipath ; ionsopheric scintillation ; low latitude ionosphere ; 01. Atmosphere::01.02. Ionosphere::01.02.06. Instruments and techniques ; 01. Atmosphere::01.02. Ionosphere::01.02.07. Scintillations
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: book chapter
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  • 8
    Publication Date: 2020-12-14
    Description: During the International Polar Year (IPY), one area of great interest is co-coordinated, multi-instrument probing of the ionosphere at high latitudes. This region is important not only for the applications that rely upon our understanding of it, but also because it contains the footprints of processes that have their origin in the interplanetary space. Many different techniques are now available for probing the ionosphere, from radar measurements to the analysis of very low frequency (VLF) wavepaths. Combining these methods provides the ability to study the ionosphere from high in the F-region to the bottom of the D-layer. Thus, coupling processes from the magnetosphere and to the neutral atmosphere can be considered. An additional dimension is through comparisons of the response of the two polar ionospheres to similar (or the same) geomagnetic activity. With more instruments available at the South Pole inter-hemispheric, studies have become easier to accomplish such that a fuller picture of the global response to Sun–Earth coupling can be painted. This paper presents a review of the current state of knowledge in ionospheric probing. It cannot provide a comprehensive guide of the work to date due to the scale of the topic.Rather it is intended to give an overview of the techniques and recent results from some of the instruments and facilities that are a part of the IPY cluster 63—Heliosphere Impact on Geospace. In this way it is hoped that the reader will gain a flavor of the recent research performed in this area and the potential for continuing collaboration and capabilities during the IPY (2007–2009).
    Description: Published
    Description: 2293-2308
    Description: 3.9. Fisica della magnetosfera, ionosfera e meteorologia spaziale
    Description: JCR Journal
    Description: reserved
    Keywords: Polar ionosphere ; International polar year ; Conjugacy ; Interhemispheric studies ; 01. Atmosphere::01.02. Ionosphere::01.02.02. Dynamics ; 01. Atmosphere::01.02. Ionosphere::01.02.06. Instruments and techniques ; 05. General::05.07. Space and Planetary sciences::05.07.01. Solar-terrestrial interaction ; 05. General::05.07. Space and Planetary sciences::05.07.02. Space weather
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 9
    Publication Date: 2020-12-14
    Description: In recent years, several groups have installed high-frequency sampling receivers in the southern middle and high latitude regions, to monitor ionospheric scintillations and the total electron content (TEC) changes. Taking advantage of the archive of continuous and systematic observations of the ionosphere on L-band by means of signals from the Global Positioning System (GPS), we present the first attempt at ionospheric scintillation and TEC mapping from Latin America to Antarctica. The climatology of the area considered is derived through Ground-Based Scintillation Climatology, a method that can identify ionospheric sectors in which scintillations are more likely to occur. This study also introduces the novel ionospheric scintillation 'hot-spot' analysis. This analysis first identifies the crucial areas of the ionosphere in terms of enhanced probability of scintillation occurrence, and then it studies the seasonal variation of the main scintillation and TEC-related parameters. The results produced by this sophisticated analysis give significant indications of the spatial/ temporal recurrences of plasma irregularities, which contributes to the extending of current knowledge of the mechanisms that cause scintillations, and consequently to the development of efficient tools to forecast space-weather-related ionospheric events.
    Description: Published
    Description: R0220
    Description: 1.7. Osservazioni di alta e media atmosfera
    Description: 3.9. Fisica della magnetosfera, ionosfera e meteorologia spaziale
    Description: JCR Journal
    Description: open
    Keywords: Scintillations ; Dynamics ; Solar-terrestrial interaction ; Space weather ; Statistical analysis ; 01. Atmosphere::01.02. Ionosphere::01.02.05. Wave propagation ; 01. Atmosphere::01.02. Ionosphere::01.02.06. Instruments and techniques ; 01. Atmosphere::01.02. Ionosphere::01.02.07. Scintillations ; 05. General::05.07. Space and Planetary sciences::05.07.02. Space weather
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 10
    Publication Date: 2017-04-04
    Description: Due to the configuration of the Earth’s magnetic field and its reconnection with the Interplanetary Magnetic Field (IMF), the high latitudes ionosphere is directly connected with outer space and, consequently, highly sensitive to the enhancement of the electromagnetic radiation and energetic particles coming from the Sun. Under such conditions the ionosphere may show the presence of small-scale structures or irregularities imbedded in the large-scale ambient plasma. These irregularities can produce short term phase and amplitude fluctuations in the carrier frequency of the radio waves which pass through them, commonly called ionospheric phase and amplitude scintillations. Since September 2003 a GPS Ionospheric Scintillation and TEC Monitor (GISTM) receiver has been deployed at the Italian Arctic station “Dirigibile Italia” in Ny Alesund (79.9° N, 11.9° E, Svalbard, Norway), in the frame of the ISACCO (Ionospheric Scintillations Arctic Campaign Coordinated Observation) project. The receiver computes and records GPS phase and amplitude scintillation parameters, as well as TEC (Total Electron Content). The measurements made by ISACCO during the superstorm of October 2003 have been here used to assess the positioning errors affecting GNSS (Global Navigation Satellite Systems, such as GPS and the European Galileo) users and their correlation with the occurrence of observed levels of scintillation.
    Description: Submitted
    Description: open
    Keywords: GPS ; Magnetic ; 01. Atmosphere::01.03. Magnetosphere::01.03.06. Instruments and techniques
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: manuscript
    Format: 232657 bytes
    Format: application/pdf
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