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  • 1
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    NmF2 trends at low and mid latitudes for the recent solar minima and comparison with IRI-2012 model (2017)
    Details
    Publication Date: 2021-01-27
    Description: The ionospheric electron density peak (NmF2) is analyzed for the recent minima of solar activity for two mid-latitude stations, Rome (41.8°N, 12.5°E, geomagnetic latitude 41.7°N, Italy) and Gibilmanna (37.9°N, 14.0°E, geomagnetic latitude 37.6°N, Italy), and for the low-latitude station of Tucuma´n (26.9°S, 294.6°E, geomagnetic latitude 17.2°S, Argentina), located in the south ridge of the equatorial ionization anomaly. An inter-minima comparison reveals that from an ionospheric point of view the last minimum of solar activity (minimum 23/24) was peculiar, with values of NmF2 lower than those recorded during the previous minima for all the stations and all the hours of the day. A more pronounced decrease is observed at Tucuma´n than at Rome and Gibilmanna. The study of the winter and semiannual anomaly shows that at mid-latitude stations the winter anomaly is not visible only for the years 2008 and 2009, which represent the deeper part of the prolonged and anomalous last solar minimum. The same is for the semi-annual anomaly. A comparison with the version 2012 of the International Reference Ionosphere model (IRI) is also carried out. The results reveal that for low solar activity the model works better at mid latitudes than at low latitudes, confirming the problems of IRI in correctly representing the low-latitude ionosphere. Nevertheless, using as input updated values of the solar and geomagnetic indices, no loss of accuracy is detected in the IRI performances for the last solar minimum with respect to the previous ones, both at mid and low latitudes.
    Description: Published
    Description: 363-374
    Description: 2A. Fisica dell'alta atmosfera
    Description: 1IT. Reti di monitoraggio
    Description: 4IT. Banche dati
    Description: JCR Journal
    Keywords: Ionosphere ; Ionospheric electron density peak ; IRI model ; Solar minimum ; Solar cycle ; Ionosphere
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 2
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    Assessment of Electromagnetic Absorption of Ice From Ice Core Measurements (2018)
    Details
    Publication Date: 2021-03-10
    Description: DOME C is located on the East Antarctic Plateau at an altitude of 3233 m above sea level and is the site of the Italian–French base, i.e., the Concordia Station ( 123∘20′ E, 75∘06′ S). It has become an important location for several scientific research studies, including astrophysics, geophysics, glaciology, and climatology, due to the perceived long-term stability and thickness of ice at this location [1], [5], [18], [24]. During the site selection and follow up of the EPICA Dome C coring project, which ultimately provided more than 800 000 years of palaeoclimatic series distributed along 3270 m [6], numerous radio-echo sounding (RES) surveys were undertaken to improve core positioning and subsequently to better leverage data and logistical infrastructures from the coring effort. These studies were conducted at very different scales over the Dome C region and revealed important information about the bedrock physiography and its physical conditions [2]– [4], [8], [9], [19], [20], [30], [31]. This study builds upon these efforts using data from two recently acquired ground-based surveys collected during 2009 and 2011 in a very small area (2.5 × 2.0 km) in the immediate proximity of the EPICA drilling site, to test advances in the acquisition and digitization technology and resolve the basal environment to unprecedented detail.
    Description: Published
    Description: 4758 - 4763
    Description: 5A. Paleoclima e ricerche polari
    Description: JCR Journal
    Keywords: Ice thickness, ; Radar antennas, ; Antarctica, ; Signal resolution, ; Receivers, ; Surface morphology ; 02.02. Glaciers
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 3
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    Analysis of Bent Wire Antenna Resonant Frequency for Different Bent Angles (2020)
    Details
    Publication Date: 2020-01-28
    Description: For the bedrock survey in the temperate glacier regions, low frequency antenna system of the airborne ground penetrating RADAR plays a very important role. A small size antenna, working at 10 MHz, would make its use easier in various radar applications. Reducing the resonant frequency of the wire dipole antenna structure, without increasing the physical size, can be attained by introducing bents in the existing structure. This paper introduces a new bent wire dipole antenna and presents the effects of bent angle of 80°, 70°, 60°, 50°, 45° and 40°of the wire antenna on the antenna parameters such as resonant frequency, S11, VSWR, gain and radiation pattern. A broadband four element equivalent circuit model of a straight dipole is used with some modifications in the R, L, C equations for the new bent wire dipole antenna by utilizing the bent angle. The frequency response of the equivalent circuit model, calculated resonant frequency values using the equations and the simulated results of the bent wire dipole antenna is compared and analyzed. As the antenna placement area inside the anechoic chamber is limited, the size of the 10MHz antenna has been scaled down by a factor of 0.01. This modifies the resonant frequency of the new structure to 1GHz. The scaled down antenna system are simulated, analyzed and tested in a GTEM cell. For bandwidth improvement of the 10 MHz antenna, a lumped element matching circuit has been designed and simulated.
    Description: Published
    Description: 1240-1251
    Description: 5A. Ricerche polari e paleoclima
    Description: JCR Journal
    Keywords: ground penetrating radar ; bent wire antenna ; 02.02. Glaciers
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 4
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    Ionosonda SDR per sondaggi obliqui (2022)
    INGV
    Details
    Publication Date: 2022-02-04
    Description: Le finalità del progetto sono quelle di realizzare un prototipo di ionosonda per sondaggi obliqui basato sul principio del radar ad onda continua modulata in frequenza, implementato tramite dispositivi programmabili innovativi che permettono di realizzare uno strumento più piccolo e trasportabile rispetto alle ionosonde classiche. La ionosonda SDR è un radar bistatico costituito da un trasmettitore, che può servire contemporaneamente diversi ricevitori situati in località differenti, e da uno o più ricevitori che possono sintonizzarsi su differenti trasmettitori che effettuano sondaggi ad orari differenti. I sondaggi obliqui permettono di mappare la ionosfera in varie parti del territorio per la verifica di modelli teorici della ionosfera e per studiare la possibilità di usare le variazioni locali del Contenuto Elettronico Totale (TEC) come segnale di possibili precursori di terremoti.
    Description: Published
    Description: 1-32
    Description: 6IT. Osservatori non satellitari
    Description: N/A or not JCR
    Keywords: ionosonda ; radar FM-CW ; software defined radio ; 01.02. Ionosphere
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 5
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    Analysis of 10 MHz Bent Wire GPR Antenna Using Different Materials (2022)
    Details
    Publication Date: 2022-02-11
    Description: Regular monitoring and tracking of the temperate glacier and polar ice sheets are necessary because of their potential impact on climate change and sea level rise. In this paper, we analyze the airborne 10 MHz bent wire ground penetrating RADAR antenna using different materials. 10 MHz GPR antenna is simulated using different materials such as silver, copper, gold, aluminum, tungsten, zinc, brass, bronze, tin, chromium, indium, lead, titanium, iron, nickel, cobalt, cast iron and graphite. From the simulation results, it is evident that, the conductivity of the material and the radiation efficiency of the antenna are directly proportional to each other. And also, if the relative permeability of the material increases, the radiation efficiency decreases. The S11, VSWR, peak gain and the radiation efficiency of the bent wire GPR antenna are presented for different materials at the solution frequency of 10 MHz.
    Description: Published
    Description: 1-3
    Description: 2IT. Laboratori analitici e sperimentali
    Description: N/A or not JCR
    Keywords: bent wire antenna ; antenna parameters ; GPR ; radiation efficiency ; 05.04. Instrumentation and techniques of general interest
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 6
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    AISP Ionosonda Programmabile (2023)
    Details
    Publication Date: 2023-01-16
    Description: Il progetto è finalizzato allo sviluppo di un prototipo di ionosonda a compressione di impulsi per rilievi verticali (coded pulse radar) che, basandosi su dispositivi SDR (Software Defined Radio), consente di realizzare uno strumento programmabile e quindi versatile e innovativo rispetto alle ionosonde classiche. La ionosonda programmabile (AISP) è una evoluzione della ionosonda AIS (Advanced Ionospheric Sounder) completamente progettata e realizzata all’ INGV e tutt’ora funzionante presso l’osservatorio ionosferico di Roma. La ionosonda AISP è una ionosonda per sondaggi verticali costituita principalmente da un dispositivo SDR che funge da trasmettitore e ricevitore dei segnali in Radio Frequenza (RF) e generatore di tutti i segnali di controllo dei dispositivi necessari al funzionamento della ionosonda come l’amplificatore di potenza in radio frequenza (RF) e le antenne. Il dispositivo SDR trasmette e riceve i segnali RF generati numericamente da un Personal Computer (PC) collegato al dispositivo attraverso la porta ethernet, questo permette un’ampia scelta di configurazioni e una grande versatilità della ionosonda così realizzata. I sondaggi verticali permettono di mappare la ionosfera in una regione specifica per la verifica di modelli teorici della ionosfera globale e per studiare la possibilità di usare le variazioni locali del Contenuto Elettronico Totale (TEC) come possibili precursori di terremoti.
    Description: Published
    Description: 1-32
    Description: 6IT. Osservatori non satellitari
    Description: N/A or not JCR
    Keywords: ionosonda ; sondaggio verticale ; software defined radio ; ionosonde ; 01.02. Ionosphere
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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