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  • 1
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    The Accuracy of Real-Time hmF2 Estimation from Ionosondes (2020)
    MDPI
    Details
    Publication Date: 2020-09-08
    Description: A total of 4991 ionograms recorded from April 1997 to December 2017 by the Millstone Hill Digisonde (42.6°N, 288.5°E) were considered, with simultaneous Ne(h)[ISR] profiles recorded by the co-located Incoherent Scatter Radar (ISR). The entire ionogram dataset was scaled with both the Autoscala and ARTIST programs. The reliability of the hmF2 values obtained by ARTIST and Autoscala was assessed using the corresponding ISR values as a reference. Average errors Δ and the root mean square errors RMSE were computed for the whole dataset. Data analysis shows that both the Autoscala and ARTIST systems tend to underestimate hmF2 values with |Δ| in all cases less than 10 km. For high magnetic activity ARTIST offers better accuracy than Autoscala, as evidenced by RMSE[ARTIST] 〈 RMSE[Autoscala], under both daytime and nighttime conditions, and considering all hours of the day. Conversely, under low and medium magnetic activity Autoscala tends to estimate hmF2 more accurately than the ARTIST system for both daytime and nighttime conditions, when RMSE[Autoscala] 〈 RMSE[ARTIST]. However, RMSE[Autoscala] slightly exceeds RMSE[ARTIST] for the day as a whole. RMSE values are generally substantial (RMSE 〉 16 km in all cases), which places a limit on the results obtainable with real-time models that ingest ionosonde data.
    Description: Published
    Description: id 2671
    Description: 2A. Fisica dell'alta atmosfera
    Description: JCR Journal
    Keywords: ionosonde ; ionograms ; automatic scaling ; electron density profile ; Incoherent Scatter Radar ; real-time ionospheric models
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 2
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    Oblique Ionograms Automatic Scaling Algorithm OIASA application to the ionograms recorded by Ebro observatory ionosonde (2018)
    Details
    Publication Date: 2020-11-26
    Description: The oblique ionograms automatic scaling algorithm (OIASA), developed at the INGV for the identification of trace of oblique ionograms, allows the determination of the maximum usable frequency (MUF) for communication between the transmitter and receiver, automatically rejecting poor quality ionograms. A test of the algorithm using data from a campaign of oblique soundings between Dourbes (50.1°N, 4.6°E) and Roquetes (40.8°N, 0.5°E) has been performed. Oblique soundings from three different campaigns have been studied, covering different geomagnetic conditions, in order to study the behavior of the autoscaling algorithm under quiet and perturbed geomagnetic periods. The reported results demonstrate that OIASA performance is not influenced by geomagnetic or ionospheric activity conditions. This demonstrates a satisfactory performance of the automatic scaling algorithm, even under different geomagnetic conditions, the potential application of OIASA as a near-real-time tool for ionospheric monitoring purposes, and its performance for tracking ionospheric effects caused by space weather events.
    Description: Published
    Description: A10
    Description: 2A. Fisica dell'alta atmosfera
    Description: JCR Journal
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 3
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    L-band scintillations and calibrated total electron content gradients over Brazil during the last solar maximum (2018)
    Details
    Publication Date: 2020-12-14
    Description: This work presents a contribution to the understanding of the ionospheric triggering of L-band scintillation in the region over São Paulo state in Brazil, under high solar activity. In particular, a climatological analysis of Global Navigation Satellite Systems (GNSS) data acquired in 2012 is presented to highlight the relationship between intensity and variability of the total electron content (TEC) gradients and the occurrence of ionospheric scintillation. The analysis is based on the GNSS data acquired by a dense distribution of receivers and exploits the integration of a dedicated TEC calibration technique into the Ground Based Scintillation Climatology (GBSC), previously developed at the Istituto Nazionale di Geofisica e Vulcanologia. Such integration enables representing the local ionospheric features through climatological maps of calibrated TEC and TEC gradients and of amplitude scintillation occurrence. The disentanglement of the contribution to the TEC variations due to zonal and meridional gradients conveys insight into the relation between the scintillation occurrence and the morphology of the TEC variability. The importance of the information provided by the TEC gradients variability and the role of the meridional TEC gradients in driving scintillation are critically described.
    Description: Published
    Description: A36
    Description: 2A. Fisica dell'alta atmosfera
    Description: JCR Journal
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 4
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    Accuracy assessment of the MUF(3000) nowcasting for PECASUS Space Weather services (2020)
    IEEE
    Details
    Publication Date: 2020-10-27
    Description: The Pan-European Consortium for Aviation Space Weather User Services (PECASUS) is one of the three global Space Weather Centers appointed by the International Civil Aviation Organization (ICAO) to generate Space Weather advisories for aviation users. One of the key operational 24/7 products developed by INGV for the HF domain is the MUF(3000) nowcasting, based on a mapping procedure over Europe, which makes use of the available real-time measurements in different locations, and the Ordinary Kriging method for spatial interpolation. The outputs of this procedure have been analysed during three strong geomagnetic storms, and the results have been compared on the basis of the Root Mean Square Error values obtained between predicted and measured MUF(3000) values at two different test stations. A good accuracy is achieved during the considered storm periods, being the overall Root Mean Square Error values at the test stations less than 2 MHz. However, particular cases show that this method could miss possible sudden ionospheric perturbations, and the effect of erroneous data on the accuracy estimation.
    Description: Published
    Description: Rome (Italy)
    Description: 2A. Fisica dell'alta atmosfera
    Keywords: ionosonde ; nowcasting service ; space weather ; aviation ; HF COM
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: Conference paper
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  • 5
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    A method for automatic detection of equatorial spread-F in ionograms (2019)
    Details
    Publication Date: 2021-03-16
    Description: A method is presented for automatic detection of spread-F. The method is based on an image recognition technique and is applied to ionograms recorded at the ionospheric station of Tucumán (26.9°S, 294.6°E). The performance achieved is statistically evaluated and demonstrated with significant examples. The proposed method improves Autoscala's ability to reject ionograms with insufficient information, including those featuring Spread-F. Automatic identification of cases of spread-F is of additional interest in Space Weather applications, when it helps detect degraded radio propagation conditions. The present data analysis is a retrospective study but forms the basis for real-time application as an extension of Autoscala’s capabilities.
    Description: Published
    Description: 337-342
    Description: 2A. Fisica dell'alta atmosfera
    Description: JCR Journal
    Keywords: Ionosonde ; Ionograms ; Spread-F ; Automatic scaling ; 01.02. Ionosphere
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 6
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    The accuracy of data from ionosondes for the estimation of hm F2 and the identification of global change in the ionosphere (2019)
    Elsevier Science Limited
    Details
    Publication Date: 2019-09-26
    Description: A long temporal series of simulated ionograms was generated with a superimposed secular variation of 14 km/century on the hmF2 parameter. These ionograms were interpreted by the automatic scaling program Autoscala. By applying four different empirical formulas, four artificial series of hmF2 were generated and then processed with the same methods used by other authors for real data sets. Data analysis of the simulated ionograms revealed the artificially imposed long-term trend. These results lead to the conclusion, that regardless of the empirical formula used, the accuracy of hmF2 from ionosonde measurements would be adequate to observe a long-term trend of 14 km/century. 2013 COSPAR. Published by Elsevier Ltd. All rights reserved.
    Description: Published
    Description: 569-574
    Description: 2A. Fisica dell'alta atmosfera
    Description: JCR Journal
    Keywords: Ionograms; Ionospheric models; Ionospheric trends; Greenhouse effect ; 01.02. Ionosphere ; 01.01. Atmosphere
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 7
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    Triple splitting and z-rays in polar ionograms (2018)
    Details
    Publication Date: 2018-03-26
    Description: The theory of propagation in a direction almost parallel to the Earth’s magnetic field is reviewed, calculating the group refractive index of the ordinary ray in the presence of electron-neutral collisions. An electron density profile is estimated from the ordinary trace and is used to compute the z-ray trace. It is shown that this reconstruction can help to identify the rare cases of z-rays from among the numerous cases of duplicate ordinary traces, due to reflection from two different directions. Received 13 June 2014, accepted 10 December 2014
    Description: Published
    Description: 383-387
    Description: 2A. Fisica dell'alta atmosfera
    Description: JCR Journal
    Keywords: ionosonde, ionosphere, radio propagation ; 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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  • 8
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    A regional adaptive and assimilative three-dimensional ionospheric model (2018)
    Details
    Publication Date: 2018-03-26
    Description: A regional adaptive and assimilative three-dimensional (3D) ionospheric model is proposed. It is able to ingest real-time data from different ionosondes, providing the ionospheric bottomside plasma frequency fp over the Italian area. The model is constructed on the basis of empirical values for a set of ionospheric parameters Pi[base] over the considered region, some of which have an assigned variation ΔPi. The values for the ionospheric parameters actually observed at a given time at a given site will thus be Pi = Pi[base] + ΔPi. These Pi values are used as input for an electron density N(h) profiler. The latter is derived from the Advanced Ionospheric Profiler (AIP), which is software used by Autoscala as part of the process of automatic inversion of ionogram traces. The 3D model ingests ionosonde data by minimizing the root-mean-square deviation between the observed and modeled values of fp(h) profiles obtained from the associated N(h) values at the points where observations are available. The ΔPi values are obtained from this minimization procedure. The 3D model is tested using data collected at the ionospheric stations of Rome (41.8N, 12.5E) and Gibilmanna (37.9N, 14.0E), and then comparing the results against data from the ionospheric station of San Vito dei Normanni (40.6N, 18.0E). The software developed is able to produce maps of the critical frequencies foF2 and foF1, and of fp at a fixed altitude, with transverse and longitudinal cross-sections of the bottomside ionosphere in a color scale. fp(h) and associated simulated ordinary ionogram traces can easily be produced for any geographic location within the Italian region. fp values within the volume in question can also be provided.
    Description: Published
    Description: 1241-1257
    Description: 2A. Fisica dell'alta atmosfera
    Description: JCR Journal
    Keywords: Ionospheric model, Space Weather ; Assimilative three-dimensional ionospheric model
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 9
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    Improvements on foF1 estimation at polar regions (2018)
    Details
    Publication Date: 2018-09-14
    Description: The analysis of a sample of polar ionograms reveals that the DuCharme and Petrie empirical formula often fails in the foF1 estimation at polar regions. A study of the discrepancies between modeled and observed foF1 values is presented, using a data set of Antarctic ionograms from different stations. Such discrepancies have been quantitatively evaluated. Based on this study a correction to the DuCharme and Petrie formula is proposed. This correction is performed to be implemented in an improved version of Autoscala software for a particular ionospheric station, in the frame of AUSPICIO (Automatic Interpretation of Polar Ionograms and Cooperative Ionospheric Observations) project.
    Description: Unpublished
    Description: Vienna (Austria)
    Description: 2A. Fisica dell'alta atmosfera
    Keywords: ionosphere ; modeling ; ionograms ; 01. Atmosphere ; 01.02. Ionosphere ; 05.04. Instrumentation and techniques of general interest
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: Oral presentation
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  • 10
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    Geophysics for Kids: The Experience of the Istituto Nazionale di Geofisica e Vulcanologia (Italy) (2018)
    Seismological Society of America
    Details
    Publication Date: 2018-02-16
    Description: Paper describing the outreach activities at INGV.
    Description: Published
    Description: 529-535
    Description: 2TM. Divulgazione Scientifica
    Description: JCR Journal
    Keywords: Kids ; Geophysics ; 05.03. Educational, History of Science, Public Issues
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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