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  • 01. Atmosphere::01.02. Ionosphere::01.02.99. General or miscellaneous  (24)
  • INGV  (22)
  • American Institute of Physics  (1)
  • IES  (1)
  • Wuppertal : Wuppertal Institut für Klima, Umwelt, Energie
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Years
  • 1
    Publication Date: 2021-05-17
    Description: A comparison between two of the most used scintillation models and experimental data is presented. The experimental data have been derived from a GPS scintillation monitor developed at Cornell University and placed in Tucuman (Argentina), under the peak of the anomaly. The models used (GISM and WBMOD) have been run for the geophysical conditions corresponding to the measurements. The comparison is done by subdividing the information on the basis of an ionospheric grid of 5°×5° surface square boxes. The comparison has been performed for several local times, from 18 LT until 04 LT. Here, only a few cases of particular interest are shown. The goal is to understand if the models are able to forecast actual scintillation morphology (from the satellite navigation systems point of view) and if they could be used to yield an estimate of scintillation effects on satellite navigation systems.
    Description: Published
    Description: JCR Journal
    Description: open
    Keywords: ionospheric scintillations ; scintillation models ; GPS ; SBAS ; 01. Atmosphere::01.02. Ionosphere::01.02.99. General or miscellaneous ; 04. Solid Earth::04.03. Geodesy::04.03.99. General or miscellaneous
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 2
    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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  • 3
    Publication Date: 2017-04-04
    Description: COST (Co-operation in the field of Scientific and Technical Research) is an important instrument supporting co-operation among scientists and researchers across Europe now joining 35 member countries. Scientific projects in the COST framework are called COST Actions and have the objectives embodied in their respective Memorandum of Understanding (MoU). The main objectives of the COST Actions within the European ionospheric and radio propagation community have been: to study the influence of upper atmospheric conditions on terrestrial and Earthspace communications, to develop methods and techniques to improve existing and generate new ionospheric and propagation models over Europe for telecommunication and navigation applications and to transfer the results to the appropriate national and international organizations, institutions and industry dealing with the modern communication systems. This paper summarises in brief the background and historical context of four ionospheric COST Actions and outlines their main objectives and results. In addition, the paper discusses the dissemination of the results and the collaboration among the participating institutions and researchers.
    Description: DRS Codem Systems Ball Aerospace Corporation University of Massachusetts Lowell
    Description: Published
    Description: Lowell, Massachusetts, U.S.A., April 29, 2007
    Description: 3.9. Fisica della magnetosfera, ionosfera e meteorologia spaziale
    Description: open
    Keywords: Physics of the Ionosphere ; 01. Atmosphere::01.02. Ionosphere::01.02.99. General or miscellaneous ; 05. General::05.07. Space and Planetary sciences::05.07.02. Space weather
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: Conference paper
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  • 4
    Publication Date: 2017-04-03
    Description: The current COST (Co-operation in the field of Scientific and Technical Research) Action 296 on Mitigation of Ionospheric Effects on Radio Systems, along with previous COST238 (Prediction and Retrospective Ionospheric Modelling over Europe), COST251 (Improved Quality of Service in Ionospheric Telecommunication Systems Planning and Operation) and COST271 (Effects of the Upper Atmosphere on Terrestrial and Earth-Space Communications) Actions have addressed investigations of the different effects of the ionosphere on terrestrial telecommunication systems and on Earth-space systems. Throughout their lifetime of 20 years, these COST actions have achieved a great deal in long-term archiving of synoptic soundings of the state of the ionosphere, in enhancing understanding of the morphology of the ionosphere and its dependence on space weather and in producing ionosphere-plasmasphere as well as propagation models for terrestrial radio services available to variety of radio users. Besides the formal contributions to ITU-R and the contributions to international organisations such as URSI, COSPAR, EGU and ESA, these COST Actions have provided a forum for the establishment of collaborative European initiatives, a centre of expertise and excellence in ionosphere knowledge when none other equivalent in Europe or elsewhere exists. In this paper, we review the main achievements of the COST 238, 251 and 271 actions as developed in the past studies.
    Description: ONR - Office of Naval Research, Airforce Office of Scientific Research, U.R.S.I.
    Description: Published
    Description: Crowne Plaza Old Town, Alexandria, Virginia, May 13-15, 2008
    Description: 3.9. Fisica della magnetosfera, ionosfera e meteorologia spaziale
    Description: open
    Keywords: Ionosphere ; Radio Propagation ; Monitoring and Modelling ; 01. Atmosphere::01.02. Ionosphere::01.02.99. General or miscellaneous ; 05. General::05.07. Space and Planetary sciences::05.07.02. Space weather
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: Conference paper
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  • 5
    Publication Date: 2019-11-04
    Description: Various modern applications of empirical electron density models need realistic structures of the electron density distribution with smaller scales than the model background. Travelling Ionospheric Disturbances (TIDs) produce three dimensional and time dependent disturbances of the background ionization. We present a TID model suitable to «modulate» large scale electron density distributions by multiplication. A model TID takes into account the forward tilt of the disturbance wave front, a distinct vertical structure, a fan type horizontal radiation characteristic, geometric dilution and attenuation. More complicated radiation patterns can be constructed by means of superposition. The model TIDs originate from source regions which can be chosen arbitrarily. We show examples for TID modulations of the background model family developed at Trieste and Graz (NeQuick, COSTprof and NeUoG-plas).
    Description: Published
    Description: JCR Journal
    Description: open
    Keywords: ionosphere ; electron density models ; Travelling Ionospheric Disturbances ; TID model ; 01. Atmosphere::01.02. Ionosphere::01.02.99. General or miscellaneous ; 01. Atmosphere::01.02. Ionosphere::01.02.05. Wave propagation
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 6
    Publication Date: 2017-04-04
    Description: Radar technology has for a long time used various systems that allow detection under high-resolution conditions, while emitting at the same time low peak power. Among these systems, transmitted pulse encoding by means of biphasic codes has been used for the advanced ionospheric sounder that was developed by the AIS-INGV ionosonde. In the receiving process, suitable decoding of the signal must be accomplished. This can be achieved in both the time and the frequency domains. Focusing on the time domain, different approaches are possible. In this study, two of these approaches have been compared, using data acquired by the AIS-INGV and processed by means of software tools (mainly Mathcad©). The analysis reveals the differences under both noiseless and noisy conditions, although this does not allow the conclusive establishment as to which method is better, as each of them has benefits and drawbacks.
    Description: Published
    Description: 1-11
    Description: 1.7. Osservazioni di alta e media atmosfera
    Description: JCR Journal
    Description: open
    Keywords: Complementary code ; Correlation ; Pulse compression ; Ionosphere ; Radar ; Time domain ; 01. Atmosphere::01.02. Ionosphere::01.02.99. General or miscellaneous ; 01. Atmosphere::01.02. Ionosphere::01.02.06. Instruments and techniques
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 7
    Publication Date: 2019-11-04
    Description: Results derived from analysing the ionosphere response to faint and bright solar flares are presented. The analysis used technology of a global detection of ionospheric effects from solar flares as developed by the authors, on the basis of phase measurements of the Total Electron Content (TEC) in the ionosphere using an international GPS network. The essence of the method is that use is made of appropriate filtering and a coherent processing of variations in the TEC which is determined from GPS data, simultaneously for the entire set of visible GPS satellites at all stations used in the analysis. This technique is useful for identifying the ionospheric response to faint solar flares (of X-ray class C) when the variation amplitude of the TEC response to separate line-on-sight to GPS satellite is comparable to the level of background fluctuations. The dependence of the TEC variation response amplitude on the bright flares location on the Sun is investigated
    Description: Published
    Description: JCR Journal
    Description: open
    Keywords: ionopshere ; Total Electron Content ; 01. Atmosphere::01.02. Ionosphere::01.02.99. General or miscellaneous
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 8
    Publication Date: 2019-11-04
    Description: The deviations of hourly f 0 F 2 from monthly medians for 20 stations in Europe during the period 1958-1998 are studied. Spectral analysis is used to show that, both for original data (for each hour) and for the deviations from monthly medians, the deterministic components are the harmonics of 11 years (solar cycle), 1 year and its harmonics, 27 days and 12 h 50.49 m (2nd harmonic of lunar rotation period L 2 ) periodicities. Using histograms for one year samples, it is shown that the deviations from monthly medians are nearly zero mean (mean 〈 0.5) and approximately Gaussian (relative difference range between %10 to %20) and their standard deviations are larger for daylight hours (in the range 5-7). It is shown that the amplitude distribution of the positive and negative deviations is nearly symmetrical at night hours, but asymmetrical for day hours. The positive and negative deviations are then studied separately and it is observed that the positive deviations are nearly independent of R12 except for high latitudes, but negative deviations are modulated by R12 . The 90% confidence interval for negative deviations for each station and each hour is computed as a linear model in terms of R12. After correction for local time, it is shown that for all hours the confidence intervals increase with latitude but decrease above 60N. Long-term trend analysis showed that there is an increase in the amplitude of positive deviations from monthly means irrespective of the solar conditions. Using spectral analysis it is also shown that the seasonal dependency of negative deviations is more accentuated than the seasonal dependency of positive deviations especially at low latitudes. In certain stations, it is also observed that the 4th harmonic of 1 year corresponding to a periodicity of 3 months, which is missing in f 0 F 2 data, appears in the spectra of negative variations.
    Description: Published
    Description: JCR Journal
    Description: open
    Keywords: deviations ; solar cycle ; 01. Atmosphere::01.02. Ionosphere::01.02.99. General or miscellaneous
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 9
    Publication Date: 2019-11-04
    Description: In this paper hourly daily F2-layer critical frequency data recorded at Rome and one minute daily TEC data recorded at Florence were used and the relevant variabiles were calculated. It was concluded that there was no clear evidence as to how they correlated. In order to obtain a measure of the f 0 F 2 and TEC variability, the normalised differences df0 F2 and d TEC from the relevant monthly median values were also considered. Since no clear evidence could be obtained as of how df0 F2 and d TEC correlate, a new parameter, the ?Ap /?R ratio was tried. ?Ap was taken as the difference between the maximum value of Ap measured at the relevant disturbance and that corresponding at the beginning of the disturbance. ?R corresponded to the two above mentioned values of Ap. This parameter was compared to the differences of the corresponding df0 F2 values called ?df and d TEC values called ?dT. In wintertime, when ?A p /? R was negative, for the vast majority of the occurrences either ?df or ?dT was negative; ?df and ?dT were never observed to be negative at the same time whereas they were both positive in fewer than 10% of the observations. When ?A p /?R was positive then either ?df or ?dT were negative. In summertime when ?A p /?R was negative both ?df and ?dT were negative. When ?A p /?R was positive, while a positive ?df corresponded almost always to a positive ?dT, a negative ?df would equiprobably indicate either a positive or a negative ?dT.
    Description: Published
    Description: JCR Journal
    Description: open
    Keywords: ionopshere ; ionospheric modelling ; 01. Atmosphere::01.02. Ionosphere::01.02.99. General or miscellaneous
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 10
    Publication Date: 2019-11-04
    Description: High-resolution vertical electron density true height profiles from Athens Digisonde are used to calculate the electron content up to the peak of the F 2 layer (bottomside electron content) and also the topside electron content up to 1000 km, using the Huang-Reinisch method, to investigate the relative behavior of these two parameters during storm events. It was shown that the topside electron content represents roughly the 2/3 of the total electron content of the ionosphere and it is strongly affected by the geomagnetic activity, much more than the bottomside electron content. During daylight hours the values of the topside electron content exhibit intense fluctuations, while they become smoother in nature during events of night-time F 2 layer uplifting caused by the auroral activity. All these facts demonstrate that the Huang-Reinisch method provides a realistic tool for monitoring the variations of the ionospheric ionisation at a given location and it could be used in the frames of a world wide effort for the development of realistic models to accurately predict the electron content and to support effectively earth-space communications including navigation systems.
    Description: Published
    Description: JCR Journal
    Description: open
    Keywords: bottom side electron content ; topside electron content ; ionispheric storm effect ; 01. Atmosphere::01.02. Ionosphere::01.02.99. General or miscellaneous
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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