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  • 01. Atmosphere::01.02. Ionosphere::01.02.99. General or miscellaneous  (22)
  • 04.08. Volcanology
  • Data analysis / ~ processing
  • INGV  (31)
  • Inst. f. Geophys., Ruhr-Univ. Bochum
  • International Union of Crystallography (IUCr)
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Keywords
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  • 1
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    Continuous monitoring of CO2 and H2S air concentration and soil CO2 flux survey for gas hazard assessment at Tor Caldara nature reserve (Anzio, Italy). (2020)
    INGV
    Details
    Publication Date: 2020-12-10
    Description: Tor Caldara natural reserve hosts the southernmost discharge of endogenous gas of Colli Albani volcano (mostly CO2 with a relevant H2S content up to 6.3 vol.%). Gas discharges in zones where past sulfur mining removed the impervious surficial cover (e.g. Miniera Grande and Miniera Piccola) and along tectonic fissures. A structural study of the reserve has shown the presence of two zones with different characteristics: prevailing directions NS and N30° in the northern zone; EW and N60° in the southern one. In MarchJuly 2012 a geochemical study was carried out, including a soil CO2 flux survey and continuous monitoring (from 2 to 11 days) of air concentration of CO2 and H2S in 12 sites of the reserve. Environmental parameters were also monitored. Total diffuse soil flux of endogenous CO2 was estimated to 17.48 ton*day1 from 1,259 measurements over a 0.47 km2 surface, with 6.56 ton*day1 only from Miniera Grande. This is the second highest value of soil CO2 flux at Miniera Grande, after that of 2005 (9.25 ton*day1) and is significantly higher than in 2009 (1.20 ton*day1). As both the 2005 and 2012 surveys were made shortly after earthquakes with epicentres near to Tor Caldara (max ML= 4.7 in 2005 and 3.5 in 2012), data confirm that soil CO2 flux increases during earthquakes because of seismic rock microfracturing and soil shaking. Hazardous air concentrations have been found only for H2S, up to immediately lethal values (5651,124 ppm) and with potentially lethal values (≥ 250 ppm) long persisting (up to 12h27’) in several no wind nights. Instead, the CO2 air concentration remained always well below dangerous levels (maximum recorded value = 2.1 vol.%). The most hazardous gas releasing sites were found in Miniera Grande and in a small pond NE of Miniera Piccola, where the carcasses of mammals and other small animals are frequently found. The killer gas is H2S, and the dangerous sites should be appropriately fenced to prevent access to people and animals.
    Description: Regione Lazio Civil Protection Department
    Description: Published
    Description: 1-48
    Description: 6A. Geochimica per l'ambiente e geologia medica
    Description: JCR Journal
    Keywords: Tor Caldara gas hazard assessment; Soil CO2 flux; CO2 and H2S air concentration monitoring ; 04.08. Volcanology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 2
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    Comparison of ionospheric scintillation models with experimental data for satellite navigation applications (2006)
    INGV
    Details
    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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  • 3
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    An interhemispheric comparison of GPS phase scintillation with auroral emission observed at the South Pole and from the DMSP satellite (2013)
    INGV
    Details
    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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  • 4
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    The TID model for modulation of large scale electron density models (2006)
    INGV
    Details
    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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  • 5
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    Validation of an integrated satellite-data-driven response to an effusive crisis: the April–May 2018 eruption of Piton de la Fournaise (2020)
    INGV
    Details
    Publication Date: 2020-06-17
    Description: Satellite‐based surveillance of volcanic hot spots and plumes can be coupled with modeling to allow ensemble‐based approaches to crisis response. We complete benchmark tests on an effusive crisis response protocol aimed at delivering product for use in tracking lava flows. The response involves integration of four models: MIROVA for discharge rate (TADR), the ASTER urgent response protocol for delivery of high‐spatial resolution satellite data, DOWNFLOW for flow path projections, and PyFLOWGO for flow run‐out. We test the protocol using the data feed available during Piton de la Fournaise’s April–May 2018 eruption, with product being delivered to the Observatoire du Piton de la Fournaise via Google Drive. The response was initialized by an alert at 19:50Z on 27 April 2018. Initially DOWNFLOW‐FLOWGO were run using TADRs typical of Piton de la Fournaise, and revealed that flow at 〉120 m 3 /s could reach the island belt road. The first TADR (10– 20 m 3 /s) was available at 09:55Z on 28 April, and gave flow run‐outs of 1180–2510 m. The latency between satellite overpass and TADR provision was 105 minutes, with the model result being posted 15 minutes later. An InSAR image pair was completed six hours after the eruption began, and gave a flow length of 1.8 km; validating the run‐out projection. Thereafter, run‐outs were updated with each new TADR, and checked against flow lengths reported from InSAR and ASTER mapping. In all, 35 TADRs and 15 InSAR image pairs were processed during the 35‐day‐long eruption, and 11 ASTER images were delivered.
    Description: Published
    Description: VO230
    Description: 5V. Processi eruttivi e post-eruttivi
    Description: JCR Journal
    Keywords: 04.08. Volcanology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 6
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    Some considerations for different time-domain signal processing of pulse compression radar (2011)
    INGV
    Details
    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
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    A rare Mid-Würmian lithoid tuff in the Agro Pontino graben (Southern Lazio, Italy) and its identification as an Albano 5-7 related distal tephra deposit (41-36 kaBP): characteristics, provenance and palaeogeographical implications (2018)
    INGV
    Details
    Publication Date: 2019-03-26
    Description: A lithoid tuff, found in 2011 (Ricci pit, Agro Pontino, Southern Lazio, Italy), was studied for its composition, origin and palaeogeographical implications. This tuff was the first occurrence of a Würmian-age tephra layer, encountered in the coastal basins of Southern Lazio. Based on its mineralogy and isotopic composition (Sr and Nd), its stratigraphic position and the pre- and post-depositional soil forma- tion and weathering, it was identified as a distal tephra deposit from the Colli Albani volcano, connected with the Albano 5-7 eruptive stage and dating from 40-36 ka BP. The lithoid tuff consists of tephra that were slightly reworked and subsequently lithified, when this central part of the Agro Pontino graben still consisted of a non-dissected, level lagoonal plain. The study confirms the earlier established importance of this tephra layer as stratigraphic marker for Central Italy, and shows that its distribution is wider than earlier assumed, notably to the SE of the Colli Albani volcano.
    Description: Published
    Description: S109
    Description: 1V. Storia eruttiva
    Description: 5V. Processi eruttivi e post-eruttivi
    Description: JCR Journal
    Keywords: Geochronology ; Stratigraphy ; Volcanic rocks ; 04.08. Volcanology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 8
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    The response of the ionosphere to faint and bright solar flares as deduced from global GPS network data (2006)
    INGV
    Details
    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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  • 9
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    Statistical properties of the deviations of f 0 F 2 from monthly medians (2006)
    INGV
    Details
    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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  • 10
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    The effects of f0 F2 variability on TEC prediction accuracy (2006)
    INGV
    Details
    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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