Geomagnetism and Aeronomy activities in Italy during IGY, 1957/58

In 2007 several events were organized to celebrate the fiftieth anniversary of the International Geophysical Year (IGY, 1957-1958). The celebrations will last until 2009 and are taking place within different contexts: the International Polar Year (IPY), the International Heliophysical Year (IHY), the electronic Geophysical Year (eGY) and the International Year of Planet Earth (IYPE). IGY offered a very appropriate and timely occasion to undertake a series of coordinated observations of various geophysical phenomena all over the globe. Italy took part in the broad international effort stimulated by IGY. In fact, Italy participated in observations and studies in many of the proposed scientific areas, in particular Geomagnetism and Aeronomy. The Istituto Nazionale di Geofisica (ING) started the installation of observatories, and updated and ensured continuous recording of geophysical observations. Geomagnetism, ionospheric physics, seismology, and other geophysical disciplines, were advanced. Although much of the work was undertaken in Italy, some attention was also devoted to other areas of the world, in particular Antarctica, where Italy participated in seismological observations. This paper gives a summary of the Geomagnetism and Ionospheric Physics activities within IGY. Furthermore, we highlight the importance of this historical event and its outcomes for the improvement of geophysical observations and the post-IGY growth of scientific investigations in Italy

Geomagnetism and Aeronomy activities in Italy during IGY, 1957/58

In 2007 several events were organized to celebrate the fiftieth anniversary of the International Geophysical Year (IGY, 1957-1958). The celebrations will last until 2009 and are taking place within different contexts: the International Polar Year (IPY), the International Heliophysical Year (IHY), the electronic Geophysical Year (eGY) and the International Year of Planet Earth (IYPE). IGY offered a very appropriate and timely occasion to undertake a series of coordinated observations of various geophysical phenomena all over the globe. Italy took part in the broad international effort stimulated by IGY. In fact, Italy participated in observations and studies in many of the proposed scientific areas, in particular Geomagnetism and Aeronomy. The Istituto Nazionale di Geofisica (ING) started the installation of observatories, and updated and ensured continuous recording of geophysical observations. Geomagnetism, ionospheric physics, seismology, and other geophysical disciplines, were advanced. Although much of the work was undertaken in Italy, some attention was also devoted to other areas of the world, in particular Antarctica, where Italy participated in seismological observations. This paper gives a summary of the Geomagnetism and Ionospheric Physics activities within IGY. Furthermore, we highlight the importance of this historical event and its outcomes for the improvement of geophysical observations and the post-IGY growth of scientific investigations in Italy

La ionosfera: comunicare... naturalmente!

La ionosfera è la parte della media-alta atmosfera compresa tra i 60 e i 1000 km di quota. Essa è caratterizzata da una concentrazione di elettroni tale da modificare la propagazione delle onde radio che la attraversano

MIRTO: a prototype for real-time ionospheric imaging over the Mediterranean area

MIRTO (Mediterranean Ionosphere with Real-time TOmography) is a collaborative project between Istituto Nazionale di Geofisica (INGV) of Rome, the University of Bath (U.K.) and the Istituto Fisica Applicata «Nello Carrara»-Consiglio Nazionale delle Ricerche (IFAC-CNR) of Florence. The goal of the project is the development of a prototype for real-time imaging of the ionosphere over the Italian region with extension to the Mediterranean Sea. MIRTO uses an original imaging technique developed at the University of Bath and upgraded for real-time use in cooperation with IFAC. The prototype makes use of the data acquired by the real-time ionospheric and geodetic instrumentation operated by INGV. Such measurements drive the imaging algorithm to produce the image of electron density as well as maps and movies of the Total Electron Content (TEC) over the considered area

GPS positioning errors during the space weather event of October 2003

Due to the configuration of the Earth’s magnetic field and its reconnection with the Interplanetary Magnetic Field (IMF), the high latitudes ionosphere is directly connected with outer space and, consequently, highly sensitive to the enhancement of the electromagnetic radiation and energetic particles coming from the Sun. Under such conditions the ionosphere may show the presence of small-scale structures or irregularities imbedded in the large-scale ambient plasma. These irregularities can produce short term phase and amplitude fluctuations in the carrier frequency of the radio waves which pass through them, commonly called ionospheric phase and amplitude scintillations. Since September 2003 a GPS Ionospheric Scintillation and TEC Monitor (GISTM) receiver has been deployed at the Italian Arctic station “Dirigibile Italia” in Ny Alesund (79.9° N, 11.9° E, Svalbard, Norway), in the frame of the ISACCO (Ionospheric Scintillations Arctic Campaign Coordinated Observation) project. The receiver computes and records GPS phase and amplitude scintillation parameters, as well as TEC (Total Electron Content). The measurements made by ISACCO during the superstorm of October 2003 have been here used to assess the positioning errors affecting GNSS (Global Navigation Satellite Systems, such as GPS and the European Galileo) users and their correlation with the occurrence of observed levels of scintillation

L'osservatorio ionosferico in Artide e Antartide: osservazioni sperimentali e risultati scientifici

The Italian Upper Atmosphere Observatory at polar latitude was firstly established during the Antarctic campaign 1990-1991 to support the telecommunication logistic activity of the National Program for Antarctic Research (PNRA). The Istituto Nazionale di Geofisica e Vulcanologia (INGV), formerly Istituto Nazionale di Geofisica (ING), was involved in this action as the long time experience in HF radar, ionospheric sounding and ionospheric prediction services for radio communication purposes, managing two of the most important and historical ionospheric observatories all over the world: Rome (41.8N, 12.5E) and Gibilmanna (37.9 N, 14.0 E). Since that time, starting from 1993 up to now, several research projects have been carried on focusing on the multi instruments upper atmosphere observations in Arctic and Antarctica with the aim to study the polar ionosphere in different time and space domains, contributing both to the Global Change and to the emerging Space Weather needs. Here we briefly report on the experimental activities as well on the main scientific results obtained highlighting the latest findings in the field of bipolar GNSS (Global Navigation Satellite Systems) ionospheric scintillation measurements and investigation

Space weather challenges of the polar cap ionosphere

This paper presents research on polar cap ionosphere space weather phenomena conducted during the European Cooperation in Science and Technology (COST) action ES0803 from 2008 to 2012. The main part of the work has been directed toward the study of plasma instabilities and scintillations in association with cusp flow channels and polar cap electron density structures/patches, which is considered as critical knowledge in order to develop forecast models for scintillations in the polar cap. We have approached this problem by multi-instrument techniques that comprise the EISCAT Svalbard Radar, SuperDARN radars, in-situ rocket, and GPS scintillation measurements. The Discussion section aims to unify the bits and pieces of highly specialized information from several papers into a generalized picture. The cusp ionosphere appears as a hot region in GPS scintillation climatology maps. Our results are consistent with the existing view that scintillations in the cusp and the polar cap ionosphere are mainly due to multi-scale structures generated by instability processes associated with the cross-polar transport of polar cap patches. We have demonstrated that the SuperDARN convection model can be used to track these patches backward and forward in time. Hence, once a patch has been detected in the cusp inflow region, SuperDARN can be used to forecast its destination in the future. However, the high-density gradient of polar cap patches is not the only prerequisite for high-latitude scintillations. Unprecedented highresolution rocket measurements reveal that the cusp ionosphere is associated with filamentary precipitation giving rise to kilometer scale gradients onto which the gradient drift instability can operate very efficiently. Cusp ionosphere scintillations also occur during IMF BZ north conditions, which further substantiates that particle precipitation can play a key role to initialize plasma structuring. Furthermore, the cusp is associated with flow channels and strong flow shears, and we have demonstrated that the Kelvin- Helmholtz instability process may be efficiently driven by reversed flow events

Long-term trends in the ionosphere and upper atmosphere parameters

The first part of the paper is directed to the investigation of the practical importance of possible longterm trends in the F2-layer for ionospheric prediction models. Using observations of about 50 different ionosonde stations with more than 30 years data series of foF2 and hmF2, trends have been derived with the solar sunspot number R12 as index of the solar activity. The final result of this trend analysis is that the differences between the trends derived from the data of the individual stations are relatively large, the calculated global mean values of the foF2 and hmF2 trends, however, are relatively small. Therefore, these small global trends can be neglected for practical purposes and must not be considered in ionospheric prediction models. This conclusion is in agreement with the results of other investigations analyzing data of globally distributed stations. As shown with the data of the ionosonde station Tromsø, however, at individual stations the ionospheric trends may be markedly stronger and lead to essential effects in ionospheric radio propagation. The second part of the paper deals with the reasons for possible trends in the Earth’s atmo- and ionosphere as investigated by different methods using characteristic parameters of the ionospheric D-, E-, and F-regions. Mainly in the F2-region different analyses have been carried out. The derived trends are mainly discussed in connection with an increasing greenhouse effect or by long-term changes in geomagnetic activity. In the F1-layer the derived mean global trend in foF1 is in good agreement with model predictions of an increasing greenhouse effect. In the E-region the derived trends in foE and h´E are compared with model results of an atmospheric greenhouse effect, or explained by geomagnetic effects or other anthropogenic disturbances. The trend results in the D-region derived from ionospheric reflection height and absorption measurements in the LF, MF and HF ranges can at least partly be explained by an increasing atmospheric greenhouse effect

Climatology of GPS ionospheric scintillations over high and mid-latitude European regions

We analyze data of ionospheric scintillation in the geographic latitudinal range 44°–88° N during the period of October, November and December 2003 as a first step to develop a “scintillation climatology” over Northern Europe. The behavior of the scintillation occurrence as a function of the magnetic local time and of the corrected magnetic latitude is investigated to characterize the external conditions leading to scintillation scenarios. The results shown herein, obtained merging observations from four GISTM (GPS Ionospheric Scintillation and TEC Monitor), highlight also the possibility to investigate the dynamics of irregularities causing scintillation by combining the information coming from a wide range of latitudes. Our findings associate the occurrences of the ionospheric irregularities with the expected position of the auroral oval and ionospheric troughs and show similarities with the distribution in magnetic local time of the polar cap patches. The results show also the effect of ionospheric disturbances on the phase and the amplitude of the GPS signals, evidencing the different contributions of the auroral and the cusp/cap ionosphere

Ionospheric Observatory Development At Mario Zucchelli Station

Since 1995 Italian Ionospheric Antarctic Observatory at Terra Nova Bay, now “MARIO ZUCCHELLI”, station (geographic coordinates: 74.70°S, 164.11°E) performs continuous and systematic ionospheric vertical soundings. Long time series of continuous and accurate ionospheric observations (more than one solar cycle) are necessary for a deeper understanding of the complex phenomena occurring in the upper atmosphere at high latitude; furthermore high rate soundings (at least four soundings per hour or more) contribute to the short-time prediction of the radiopropagation conditions and to the Space Weather. During 2003–2004 Antarctic campaign a new digital ionosonde, recently developed at the Istituto Nazionale di Geofisica e Vulcanologia (INGV) in Rome, (Italy), has been installed the Ionospheric Observatory and preliminary tests have been carried out. This new Advanced Ionospheric Sounder-INGV, briefly AIS, is integrated in a stand alone system during winter time: the sounding, device settings and data sending to Rome are completely automatic and remote programmable. Ionograms are available on line at the INGV web and ftp server. The new features of the Ionospheric Observatory are presented and preliminary statistics on the reliability and validation of the experimental observation are shown and discussed