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Dipartimento di Fisica, Università “La Sapienza”, Roma, Italy
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- PublicationOpen AccessArtificial and natural electromagnetic signals revealed during two years in the Amare cave (Central Italy)(1994-11)
; ; ; ; ; ; ; ; ;Bella, F.; Dipartimento di Fisica, Università “La Sapienza”, Roma, Italy ;Bella, R.; IBM - SEMEA, Roma, Italy ;Biagi, P. F.; Dipartimento di Scienze della Terra, Università “La Sapienza”, Roma, Italy ;Caputo, M.; Dipartimento di Fisica, Università “La Sapienza”, Roma, Italy ;Della Monica, G.; Dipartimento di Fisica, Università “La Sapienza”, Roma, Italy ;Ermini, A.; Dipartimento di Fisica, Università “La Sapienza”, Roma, Italy ;Plastino, W.; Dipartimento di Fisica, Università “La Sapienza”, Roma, Italy ;Sgrigna, V.; Dipartimento di Fisica, Università “La Sapienza”, Roma, Italy; ; ; ; ; ; ; n 1990, some instrumentation was set up in the Amare cave (southern slope of the Gran Sasso chain, L'Aquila) in order to pick up electric signals ranging from 0.3 to 300 kHz, magnetic signals from 0.3 to 30 kHz and seismoacoustic signals by means of three geophones with natural frequencies of 0.3 kHz, 25 kHz and 150 kHz. Data are recorded every ten minutes on a solid state memory. The analysis of the data allows us to establish the existence of electromagnetic fields of distant origin connected with broadcastings and with tropical lightning activity and the discontinuous presence of local electric and magnetic signals, coupled with seismoacoustic ones, connected with weather events. A qualitative explanation of these near fields is given.188 325 - PublicationRestrictedA statistical analysis on the relationship between thunderstorms and the sporadic E Layer over Rome(2013-11-09)
; ; ; ; ; ; ;Barta, V.; University of West Hungary, Kitaibel P´al Doctoral School of Environmental Science, Bajcsy-Zsilinszky str. 4., H-9400 Sopron, Hungary; Research Centre for Astronomy and Earth Sciences, GGI, Hungarian Academy of Sciences, Csatkai str. 6-8., H-9400, Sopron, Hungary ;Scotto, C.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia ;Pietrella, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia ;Sgrigna, V.; Roma Tre University, Faculty ofMathematics, Physics and Natural Sciences, Dipartimento di Fisica “Edoardo Amaldi”, Via della Vasca Navale, 84, 00146, Rome, Italy ;Conti, L.; Universit`a Telematica Internazionale UNINETTUNO, Facolt`a di Ingegneria, Corso Vittorio Emanuele II, 39, 00186 Rome, Italy ;Satori, G.; Research Centre for Astronomy and Earth Sciences, GGI, Hungarian Academy of Sciences, Csatkai str. 6-8., H-9400, Sopron, Hungary; ; ; ; ; Meteorological processes (cold fronts, mesoscale convective complexes, thunderstorms) in the troposphere can generate upward propagating waves in the neutral atmosphere affecting the behaviour of the ionosphere. One type of these waves are the internal atmospheric gravity waves (AGWs) which are often generated by thunderstorms. Davis & Johnson (2005) found in low pressure systems that a localized intensification of the sporadic E layer (Es) can be attributed to lightnings. To confirm this result, we have performed two different statistical analysis using the time series of the critical frequency (foEs), the virtual height of the sporadic E layer (h’Es), and meteorological observations (lightnings, Infrared maps) over the ionospheric station of Rome (41.9◦ N, 12.5◦ E). In the first statistical analysis, we separated the days of 2009 into two groups: stormy days and fair-weather days, then we studied the occurrence and the properties of the Es separately for the two different groups. No significant differences have been found. In the second case, a superposed epoch analysis (SEA) was used to study the behaviour of the critical frequency and virtual height 100 hours before and after the lightnings. The SEA shows a statistically significant decrease in the critical frequency after the time of the lightnings, which indicates a sudden decrease in the electron density of the sporadic E layer associated with lightnings.314 27 - PublicationOpen AccessNormal and anomalous behaviour of electric, magnetic and seismoacoustic signals recorded in the Amare cave(1996-01)
; ; ; ; ; ; ; ;Bella, F.; Dipartimento di Fisica, III Università di Roma, Italy ;Biagi, P. F.; Dipartimento di Fisica, Università di Bari, Italy ;Caputo, M.; Dipartimento di Fisica, Università La Sapienza, Roma, Italy ;Della Monica, G.; Dipartimento di Fisica, III Università di Roma, Italy ;Ermini, A.; Dipartimento di Scienze e Tecnologie Fisiche ed Energetiche, Università «Tor Vergata», Roma, Italy ;Plastino, W.; Dipartimento di Fisica, III Università di Roma, Italy ;Sgrigna, V.; Dipartimento di Scienze e Tecnologie Fisiche ed Energetiche, Università «Tor Vergata», Roma, Italy; ; ; ; ; ; Since 1987 multichannel instrumentation has been recording electromagnetic and seismoacoustic emissions in the Amare cave (Gran Sasso í L'Aquila). Equipment detecting RMC (Principality of Monaco) longwave broadcasting (216 kHz) has been operating in the same place. Data collected during this period have pointed out two different phenomena called «quiet» and «perturbed» that characterize the normal behaviour of the cave. On 25 August 1992 an earthquake with M = 3.9 occurred in the Gran Sasso area and on 4 June 1993 an earthquake with M = 4.3 occurred in Umbria, 100 km to north of the Amare cave. Before these earthquakes, electromagnetic, seismoacoustic, and RMC data showed anomalies. Here we present the observed phenomenology and discuss the possibility that the anomalies can be considered precursors of the earthquakes.166 195 - PublicationOpen AccessAn overview on preseismic anomalies in LF radio signals revealed in Italy by wavelet analysis(2008-02)
; ; ; ; ;Biagi, P. F.; Dipartimento di Fisica, Università degli Studi di Bari, Italy ;Castellana, L.; Dipartimento di Fisica, Università degli Studi di Bari, Italy ;Maggipinto, T.; Dipartimento di Fisica, Università degli Studi di Bari, Italy ;Ermini, A.; Dipartimento di Ingegneria dell’Impresa, Università degli Studi di Roma Tor Vergata, Roma, Italy; ; ; Since 1996, the electric field strength of the two broadcasting stations MCO (f=216 kHz, southeast France) and CZE (f=270 kHz, Czech Republic) has been sampled every ten minutes by a receiver (AS) located in central Italy. Here, we review the results obtained by a detailed analysis applied to the data recorded from February 1996 up to December 2004. At first, the daytime and nighttime data were extracted and then, in the daytime data, the data collected in winter were separated from those collected in summer. On the second step the wavelet transform was applied. The results of this analysis are radio anomalies detected as earthquake precursors both for MCO and CZE data. In particular, regarding the MCO data, the main result was the appearance of a very clear anomaly during May-August 1998, at daytime and at nighttime. Such an anomaly can be considered as a precursor of a seismic sequence started on August 15, 1998 with 17 earthquakes (M=2.2-4.6) on the Reatini mountains, a seismogenic zone located 30 km far from the AS receiver along the path MCO-AS. As concerns with the CZE data, the first result was obtained from the summer daytime data and it was the appearance of a very clear anomaly during August-September 1997, that can be considered a precursor of the two earthquakes with magnitude M=5.6 and M=5.9 that occurred on September 26 in the Umbria-Marche region (Central Italy). The second result was the appearance of an anomaly during February-March 1998, at daytime and at nighttime, that can be related to the preparatory phase of the strong (M=5.1-6.0) Slovenia seismic sequence that occurred in a zone lying in the middle of the CZE-AS path.151 276 - PublicationOpen AccessDisturbances in LF radio-signals as seismic precursors(2001-10)
; ; ; ; ; ; ; ;Biagi, P. F.; INFM-Dipartimento di Fisica, Università di Bari, Italy ;Piccolo, R.; INFM-Dipartimento di Fisica, Università di Bari, Italy ;Ermini, A.; Dipartimento di Scienze e Tecnologie Fisiche ed Energetiche, Università «Tor Vergata», Roma, Italy ;Martellucci, S.; Dipartimento di Scienze e Tecnologie Fisiche ed Energetiche, Università «Tor Vergata», Roma, Italy ;Bellecci, C.; Dipartimento di Scienze e Tecnologie Fisiche ed Energetiche, Università «Tor Vergata», Roma, Italy ;Hayakawa, M.; Department of Electronic Engineering, The University of Electro-Communications, Chofu, Tokyo, Japan ;Kingsley, S. P.; Sheffield Centre for Earth Observation Science, University of Sheffield, U.K.; ; ; ; ; ; Low Frequency (LF) radio signals lie in the band 30-300 kHz. Monitoring equipment able to measure the electric strength of such signals, at field sites with very low noise levels, were designed and assembled in Italy. From 1993 onwards, the electric field strength of the MCO (216 kHz, France) broadcasting station has been measured at two sites in Central Italy. At the end of 1996, radio signals from the CLT (189 kHz, Italy) and the CZE (270 kHz, Czech Republic) broadcasting stations were included in the measurements. During this monitoring period, evident attenuation of the electric field strength in some of the radio signals was observed at some of the receivers. The duration of the attenuation observed was several days and so it could have been related to particular meteorological conditions. On the other hand, this phenomenon could also represent precursors of moderate (3.0 =M =3.5) earthquakes that occurred near the receivers (within 50 km) along the transmitter-receiver path. In this case it is possible that some local troposphere defocusing of the radio signals, produced by the pre-seismic processes, might have occurred. These observations were related only to moderate earthquakes and in these cases it may be that suitable meteorological conditions are needed to observe the effect. During February-March 1998 at one measuring site, we observed a significant increase in the CZE electric field strength. Unfortunately, the data of the other receiver could not be used in this case because of frequent interruptions in the recordings. The increase might have been a precursor of a strong earthquake (M = 5.3) that occurred on March 26, 1998 in the Umbria-Marche zone at a location over 100 km from the receiver, but which lay along the transmitter-receiver path. In this case, it is possible that an ionospheric disturbance, produced by the pre-seismic processes, might have occurred. If this pre-seismic behaviour of the LF signals could be confirmed then this type of precursor would seem capable of giving information on the direction, and perhaps even the rough location, of a forthcoming earthquake.155 488 - PublicationRestrictedGNSS data filtering optimization for ionospheric observation(2015)
; ; ; ; ; ; ;; ; ;; In the last years, the use of GNSS (Global Navigation Satellite Systems) data has been gradually increasing, for both scientific studies and technological applications. High-rate GNSS data, able to generate and output 50-Hz phase and amplitude samples, are commonly used to study electron density irregularities within the ionosphere. Ionospheric irregularities may cause scintillations, which are rapid and random fluctuations of the phase and the amplitude of the received GNSS signals. For scintillation analysis, usually, GNSS signals observed at an elevation angle lower than an arbitrary threshold (usually 15 , 20 or 30 ) are filtered out, to remove the possible error sources due to the local environment where the receiver is deployed. Indeed, the signal scattered by the environment surrounding the receiver could mimic ionospheric scintillation, because buildings, trees, etc. might create diffusion, diffraction and reflection. Although widely adopted, the elevation angle threshold has some downsides, as it may under or overestimate the actual impact of multipath due to local environment. Certainly, an incorrect selection of the field of view spanned by the GNSS antenna may lead to the misidentification of scintillation events at low elevation angles. With the aim to tackle the non-ionospheric effects induced by multipath at ground, in this paper we introduce a filtering technique, termed SOLIDIFY (Standalone OutLiers IDentIfication Filtering analYsis technique), aiming at excluding the multipath sources of non-ionospheric origin to improve the quality of the information obtained by the GNSS signal in a given site. SOLIDIFY is a statistical filtering technique based on the signal quality parameters measured by scintillation receivers. The technique is applied and optimized on the data acquired by a scintillation receiver located at the Istituto Nazionale di Geofisica e Vulcanologia, in Rome. The results of the exercise show that, in the considered case of a noisy site under quiet ionospheric conditions, the SOLIDIFY optimization maximizes the quality, instead of the quantity, of the data.158 8 - PublicationRestrictedElectromagnetic propagation features of ground-penetrating radars for the exploration of Martian subsurface(2006)
; ; ; ; ; ; ; ; ; ; ; ; ;Pettinelli, E.; Dipartimento di Fisica “E. Amaldi”, Università “Roma Tre”, Roma and INFM-Viterbo, Italy ;Vannaroni, G.; Istituto di Fisica dello Spazio Interplanetario, INAF, Roma, Italy ;Mattei, E.; Dipartimento di Scienze Ambientali, Università della Tuscia, Viterbo and INFM-Viterbo, Italy ;Di Matteo, A.; Dipartimento di Fisica “E. Amaldi”, Università “Roma Tre”, Roma and INFM-Viterbo, Italy ;Paolucci, F.; Dipartimento di Fisica “E. Amaldi”, Università “Roma Tre”, Roma and INFM-Viterbo, Italy ;Pisani, A. R.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;Cereti, A.; Istituto di Fisica dello Spazio Interplanetario, INAF, Roma, Italy ;Del Vento, D.; Istituto di Fisica dello Spazio Interplanetario, INAF, Roma, Italy ;Burghignoli, P.; Dipartimento di Ingegneria Elettronica, Università “La Sapienza”, Roma, Italy ;Galli, A.; Dipartimento di Ingegneria Elettronica, Università “La Sapienza”, Roma, Italy ;De Santis, A.; Dipartimento di Scienze Ambientali, Università della Tuscia, Viterbo and INFM-Viterbo, Italy ;Bella, F.; Dipartimento di Fisica “E. Amaldi”, Università “Roma Tre”, Roma and INFM-Viterbo, Italy; ; ; ; ; ; ; ; ; ; ; In this work, the effects of magnetic inclusions in a Mars-like soil are considered with reference to the electromagnetic propagation features of ground-penetrating radars (GPRs). Low-frequency and time-domain techniques, using L-C-R meters and TDR instruments, respectively, are implemented in laboratory experimental set-ups in order to evaluate complex permittivity and permeability and wave velocity for different scenarios of a dielectric background medium (silica) with magnetic inclusions (magnetite). Attenuation and maximum detection ranges have also been evaluated by taking into account a realistic GPR environment, which includes the transmitting/receiving antenna performance and the complex structure of the subsurface. The analysis and the interpretation of these results shed new light on the significant influence of magnetic inclusions on the performance of Martian orbiting and rover-driven GPRs.260 33