Fading in the HF ionospheric channel and the role of irregularities

Bianchi, C.; Baskaradas, James A.; Pezzopane, Michael; Pietrella, M.; Sciacca, U.; Zuccheretti, E.

doi:10.1016/j.asr.2013.03.035

Cited by 11 publications

(6 citation statements)

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“…In fact, very large deviations on the direction of arrival of HF radio signals, with bearings up to ± 100°, have been attributed to the trough at subauroral latitudes (Siddle et al 2004a(Siddle et al , 2004b, as well as to the presence of patches and arcs of enhanced electron density (Warrington et al 1997). Moreover, as also observed at mid-latitudes, electron density inhomogeneities roughen the reflecting surface, increasing the directional spread of signals arriving at the receiver (Bianchi et al 2013). The complexity of the structure and dynamics of the high latitude ionosphere is clearly reflected in ground-based observations based on vertical ionosonde soundings.…”

Section: Discussionmentioning

confidence: 94%

“…Moreover, as also observed at mid-latitudes, electron density inhomogeneities roughen the reflecting surface, increasing the directional spread of signals arriving at the receiver (Bianchi et al . 2013). The complexity of the structure and dynamics of the high latitude ionosphere is clearly reflected in ground-based observations based on vertical ionosonde soundings.…”

Section: Discussionmentioning

confidence: 99%

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NeQuick2 and IRI2012 models applied to mid and high latitudes, and the Antarctic ionosphere

et al. 2017

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Within the framework of the AUSPICIO (AUtomatic Scaling of Polar Ionograms and Co-operative Ionospheric Observations) project, a limited sample of ionograms recorded mostly in 2001 and 2009, and to a lesser extent in 2006–07 and 2012–15, at the ionospheric observatories of Hobart and Macquarie Island (mid-latitude), Comandante Ferraz and Livingstone Island (high latitude), and Casey, Mawson, Davis and Scott Base (inside the Antarctic Polar Circle (APC)) were considered to study the capability of the NeQuick2 and IRI2012 models for predicting the behaviour of the ionosphere at mid- and high latitudes and over the Antarctic area. The applicability of NeQuick2 and IRI2012 was evaluated as i) climatological models taking as input the F10.7 solar activity index and ii) assimilative models ingesting the foF2 and hmF2 measurements obtained from the electron density profiles provided by the Adaptive Ionospheric Profiler (AIP). The statistical analysis results reveal that the best description of the ionosphere’s electron density is achieved when the AIP measurements are ingested into the NeQuick2 and IRI2012 models. Moreover, NeQuick2 performance is far better than IRI2012 performance outside the APC. Conversely, the IRI2012 model performs better than the NeQuick2 model inside the APC.

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Section: Discussionmentioning

confidence: 94%

Section: Discussionmentioning

confidence: 99%

NeQuick2 and IRI2012 models applied to mid and high latitudes, and the Antarctic ionosphere

et al. 2017

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“…The signals exhibit considerable small-scale variability or fading which is superimposed on large-scale, gradual arcs. Fading at medium and high frequencies has been investigated since the early days of radio-see Salaman (1962); Davies (1965); Rao et al (2002); Bianchi et al (2013) and references therein for reviews. The causes of fading include time-variations in absorption and focusing as discussed above.…”

Section: Data Presentationmentioning

confidence: 99%

Mapping Irregularities in the Postsunset Equatorial Ionosphere With an Expanded Network of HF Beacons

et al. 2021

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Background and MotivationOne of the most common manifestations of space weather is the spontaneous generation of broadband plasma density irregularities in the postsunset equatorial F-region ionosphere. The phenomenon, often referred to as equatorial spread F (ESF) because of the spreading it produces in ionogram traces (Booker & Wells, 1938), is attributed to interchange instability in the F region which can become unstably stratified with the cessation of photoionization. The connection between ESF and interchange instabilities was established by Woodman and La Hoz (1976) who were the first to render coherent backscatter radar profiles observed at the Jicamarca Radio Observatory in range-time-intensity (RTI) image format. Their images resembled numerical simulations of interchange instabilities in barium clouds (e.g., Ossakow, 1981). Earlier, working also at Jicamarca, Farley et al (1970) had established a causal relationship between the height of the F layer at sunset and the occurrence probability of ESF, a finding which is consistent with if not uniquely indicative of interchange instability. Later, true images of large-scale irregularities associated with ESF were observed with the ALTAIR radar on Kwajalein which can scan from horizon to horizon (Tsunoda et al., 1979). These, together with increasingly accurate and finely resolved numerical simulations, cemented the link between ESF and ionospheric interchange instability (see e.g.,

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“…However, this long‐term planning does not consider short‐term ionospheric variability, very important in HF links [ Bianchi and Meloni , , Yau et al ., ; McNamara , ; Baskaradas et al ., ]. Ionospheric irregularities generally include conditions that cannot be accurately described by standard ionospheric prediction models and events that do not follow conventional patterns predicted on the basis of their physical causes [ Bianchi et al ., ]. The ionospheric regions are highly variable and exhibit, among other irregularities, two very well known phenomena recognized as traveling ionospheric disturbances (TIDs) and sudden ionospheric disturbances (SIDs) [ Crowley and Rodrigues , ; Krasnov et al ., ].…”

Section: Ionospheric Disturbed Conditions Potentially Affecting Swingmentioning

confidence: 99%

“SWING”: A European project for a new application of an ionospheric network

et al. 2016

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The SWING (Short Wave critical Infrastructure Network based on a new Generation high survival radio communication system) is a European project aimed at studying a high survival high‐frequency (HF) radio network to link European Critical Infrastructures (ECIs). This system is thought to replace broadband internet communication, maintaining the minimum flux of essential information for the ECIs management and control, in case of wide‐scale threats, including terrorist attacks, able to put out of order internet links over the Mediterranean region. SWING is designed to evaluate the threat and increase the security awareness, as well as the level of protection, of analogous and/or interdependent ECIs. In order to meet these goals, SWING was finalized to recognize how and when the internet communication fails and to develop the standard software and hardware tools necessary for implementing communication protocols suited for a reliable and interoperable short‐wave (SW) or high‐frequency (HF) radio network backup. The internet broadband description and internet failure recognition were taken into consideration in the project but are not treated in this paper. It has been assessed that in case of complete failure of the internet broadband communication fundamental information for the management and control of ECIs over the Mediterranean region can be maintained with a HF network, even in case of moderate ionospheric perturbations.

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Fading in the HF ionospheric channel and the role of irregularities

Cited by 11 publications

References 11 publications

NeQuick2 and IRI2012 models applied to mid and high latitudes, and the Antarctic ionosphere

NeQuick2 and IRI2012 models applied to mid and high latitudes, and the Antarctic ionosphere

Mapping Irregularities in the Postsunset Equatorial Ionosphere With an Expanded Network of HF Beacons

“SWING”: A European project for a new application of an ionospheric network

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