http://hdl.handle.net/2122/97 Ricerca nel canale cerca http://www.earth-prints.org/simple-search http://hdl.handle.net/2122/6012 Titolo: Satellite traces, range spread-F occurrence, and gravity wave propagation at the southern anomaly crest<br/><br/>Autori: Cabrera, M. A.; Pezzopane, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Zuccheretti, E.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Ezquer, R. G.<br/><br/>Abstract: Range spread-F (RSF) and occurrence of “satellite” traces prior to RSF onset were studied at the southern peak of the ionospheric equatorial anomaly (EA). Ionograms recorded in September 2007 at the new ionospheric station of Tucumán, Argentina (26.9° S, 294.6° E, dip latitude 15.5° S), by the Advanced Ionospheric Sounder (AIS) developed at the Istituto Nazionale di Geofisica e Vulcanologia INGV), were considered.Satellite traces (STs) are confirmed to be a necessary precursor to the appearance of an RSF trace on the ionograms.Moreover, an analysis of isoheight contours of electron density seems to suggest a relationship between RSF occurrenceand gravity wave (GW) propagation. Tue, 18 May 2010 00:00:00 GMT http://hdl.handle.net/2122/5259 Titolo: Imaging of the Antarctic ionosphere: Experimental results<br/><br/>Autori: Yin, P.; College of Electronic Information Engineering,Civil Aviation University of China,Tianjin,China; Mitchell, C. N.; Department of Electronic and Electrical Engineering, University of Bath, Bath BA2 7AY,UK; Alfonsi, Lu.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Pinnock, M.; British Antarctic Survey, UK; Spencer, P.; Department of Electronic and Electrical Engineering, University of Bath, Bath BA2 7AY, UK; De Franceschi, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Romano, V.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Newell, P.; Johns Hopkins University, Applied Physics Laboratory, USA; Sarti, P.; Istituto Radio Astronomia (IRA)-INAF, Bologna, Italy; Negusini, M.; Istituto Radio Astronomia (IRA)-INAF, Bologna, Italy; Capra, A.; Università di Modena e Reggio Emilia, Italy<br/><br/>Abstract: Ground-based dual-frequency GPS observations can be used to create images of electron density.This is well established for the Arctic ionosphere; here one of the first results is presented for the Antarctic. Inthis study, the GPS receivers in the Antarctic are supplemented with another GPS receiver onboard CHAMP. The aim of the study is to demonstrate the technique for investigating geophysical events, forexample, an ionospheric disturbance period on 11 February 2004. The images have been validated by in-situ measurements from DMSP and CHAMP satellites, as well as Super Dual Auroral Radar Network(SuperDARN) convection patterns, which are able to confirm the location, presence, and transportation of large-scale plasma patches. This study indicates that although the convection still dominates in thehigh-latitude ionosphere, soft precipitation within the polar cap may play a role in the evolution of the polar patches. It also illustrates the potential for future multi-instrument studies of the Antarctic. Sun, 01 Nov 2009 00:00:00 GMT http://hdl.handle.net/2122/5240 Titolo: Climate of the upper atmosphere<br/><br/>Autori: Bremer, J.; Leibniz-Institute of Atmospheric Physics, Kühlungsborn, Germany; Lăstovička, J.; Institute of Atmospheric Physics, Academy of Sciences of Czech Republic, Prague, Czech Republic; Mikhailov, A. V.; Institute of Terrestrial Magnetism, Ionosphere and Radio Wave Propagation (IZMIRAN),; Altadill, D.; Observatori de l’Ebre, Universitat Ramon Llull – CSIC, Spain; Bencze, P.; Geodetic and Geophysical Research Institute, Hungarian Academy of Sciences, Sopron, Hungary; Burešová, D.; Institute of Atmospheric Physics, Academy of Sciences of Czech Republic, Prague, Czech Republic; De Franceschi, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Jacobi, C.; Institute for Meteorology, University of Leipzig, Leipzig, Germany; Kouris, S.; Electrical and Computer Engineering Department, Aristotle University of Thessaloniki, Greece; Perrone, L.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Turunen, E.; Sodankylä Geophysical Observatory, Sodankylä, Finland<br/><br/>Abstract: In the frame of the European COST 296 project (Mitigation of Ionospheric Effects on Radio Systems, MIERS)investigations of the climate of the upper atmosphere have been carried out during the last four years to obtain new information on the upper atmosphere. Mainly its ionospheric part has been analysed as the ionosphere ismost essential for the propagation of radio waves. Due to collaboration between different European partners many new results have been derived in the fields of long-term trends of different ionospheric and related atmospheric parameters, the investigations of different types of atmospheric waves and their impact on the ionosphere, the variability of the ionosphere, and the investigation of some space weather effects on the ionosphere. Sat, 01 Aug 2009 00:00:00 GMT http://hdl.handle.net/2122/5019 Titolo: Monitoring the Dynamics of the Ionosphere–Plasmasphere System by Ground-Based ULF Wave Observations<br/><br/>Autori: Vellante, M.; Dipartimento di Fisica, Università dell’Aquila, L’Aquila, Italy; Förster, M.; GeoForschungsZentrum, Potsdam, Germany; Pezzopane, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Jakowski, N.; Deutsches Zentrum für Luft- und Raumfahrt (DLR), Institut für Kommunikation und Navigation, Neustrelitz, Germany; Zhang, T. L.; Institut für Weltraumforschung, Graz, Austria; Villante, U.; Dipartimento di Fisica, Università dell’Aquila, L’Aquila, Italy; De Lauretis, M.; Dipartimento di Fisica, Università dell’Aquila, L’Aquila, Italy; Zolesi, B.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Magnes, W.; Institut für Weltraumforschung, Graz, Austria<br/><br/>Abstract: Cross-spectral analysis of ULF wave measurements recorded at ground magnetometerstations closely spaced in latitude allows accurate determinations ofmagnetospheric field line resonance (FLR) frequencies. This is a useful tool for remotesensing temporal and spatial variations of the magnetospheric plasma mass density. Thespatial configuration of the South European GeoMagnetic Array (SEGMA, 1.56 < L <1.89) offers the possibility to perform such studies at low latitudes allowing to monitor thedynamical coupling between the ionosphere and the inner plasmasphere. As an example ofthis capability we present the results of a cross-correlation analysis between FLR frequenciesand solar EUV irradiance (as monitored by the 10.7-cm solar radio flux F10.7)suggesting that changes in the inner plasmasphere density follow the short-term (27-day)variations of the solar irradiance with a time delay of 1–2 days. As an additional examplewe present the results of a comparative analysis of FLR measurements, ionospheric verticalsoundings and vertical TEC measurements during the development of a geomagneticstorm. Wed, 01 Apr 2009 00:00:00 GMT http://hdl.handle.net/2122/4542 Titolo: Probing the high latitude ionosphere from ground-based observations: The state of current knowledge and capabilities during IPY (2007–2009)<br/><br/>Autori: Alfonsi, Lu.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Kavanagh, A. J.; Space Plasma Environment and Radio Science Group, Department of Communication Systems, InfoLab 21, Lancaster University, Lancaster LA1 4WA, UK; Amata, E.; Istituto di Fisica dello Spazio Interplanetario I.N.A.F., Via del fosso del cavaliere 100, 00133 Rome, Italy; Cilliers, P.; Hermanus Magnetic Observatory (HMO), P.O. Box 32, Hermanus, South Africa; Correia, E.; Instituto Nacional de Pesquisas Espaciais (INPE), São José dos Campos, Brazil and Centro de Rádio Astronomia e Astrofísica Mackenzie (CRAAM), Universidade Presbiteriana Mackenzie, Rua da Consolação 930, CEP: 01302-907 São Paulo, Brazil; Freeman, M.; British Antarctic Survey, High Cross Madingley Road, Cambridge, UK; Kauristie, K.; Finnish Meteorological Institute, Erik Palménin aukio 1, Helsinki, Finland; Liu, R.; Polar Research Institute of China, Shanghai 200136, China; Luntama, J.-P.; Finnish Meteorological Institute, Erik Palménin aukio 1, Helsinki, Finland; Mitchell, C. N.; Department of Electrical Engineering, University of Bath, Bath BA2 7AY, UK; Zherebtsov, G. A.; Institute of Solar-Terrestrial Physics, Siberian Branch, Russian Academy of Science, Irkutsk, Russia<br/><br/>Abstract: During the International Polar Year (IPY), one area of great interest is co-coordinated, multi-instrument probing of the ionosphere at high latitudes. This region is importantnot only for the applications that rely upon our understanding of it, but also because itcontains the footprints of processes that have their origin in the interplanetary space. Many different techniques are now available for probing the ionosphere, from radar measurements to the analysis of very low frequency (VLF) wavepaths. Combiningthese methods provides the ability to study the ionosphere from high in the F-region tothe bottom of the D-layer. Thus, coupling processes from the magnetosphere and to theneutral atmosphere can be considered. An additional dimension is through comparisonsof the response of the two polar ionospheres to similar (or the same) geomagneticactivity. With more instruments available at the South Pole inter-hemispheric, studieshave become easier to accomplish such that a fuller picture of the global response toSun–Earth coupling can be painted.This paper presents a review of the current state of knowledge in ionosphericprobing. It cannot provide a comprehensive guide of the work to date due to the scale ofthe topic.Rather it is intended to give an overview of the techniques and recent resultsfrom some of the instruments and facilities that are a part of the IPY cluster63—Heliosphere Impact on Geospace. In this way it is hoped that the reader will gain aflavor of the recent research performed in this area and the potential for continuingcollaboration and capabilities during the IPY (2007–2009). Mon, 01 Dec 2008 00:00:00 GMT http://hdl.handle.net/2122/3858 Titolo: Dynamics of high-latitude pathches and associated small-scale irregularities during the October and November 2003 storms<br/><br/>Autori: De Franceschi, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Alfonsi, Lu.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Romano, V.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Aquino, M.; IESSG, The University of Nottingham, University Park, Nottingham NG7 2RD, UK; Dodson, A.; IESSG, The University of Nottingham, University Park, Nottingham NG7 2RD, UK; Mitchell, C. N.; Electronic and Electrical Engineering, University of Bath, Bath, UK; Spencer, P.; Electronic and Electrical Engineering, University of Bath, Bath, UK; Wernik, A. W.; Space Research Center, Polish Academy of Sciences, Warsaw, Poland<br/><br/>Abstract: Observations from a network of specially equipped GPS scintillation receivers in Northern Europe are used to investigate the dynamics of ionospheric plasma during the storm events of 30 October and 20 November 2003. The total electron content (TEC) and scintillation data, combined with ionospheric tomography produced by the multi-instrumentdata analysis system (MIDAS), reveal strong enhancements and steep gradients in TEC during nighttime under a prevailing negative Bz component of the interplanetary magnetic field (IMF). Amplitude and phase scintillation maxima are often co-located with the TEC gradients at the edge of plasma patches, revealing the presence of small-scale irregularities and suggesting association with a tongue of ionization (TOI) convecting in an anti-sunward direction fromthe American sector across the polar cap. Similarities and differences between the ionospheric response to the two storms are investigated. The 30 October event reveals a quite complex scenario showing two phases of plasma dynamics: the former reflects the expected convection pattern for IMF Bz southward and the latter possibly indicates a sort of TEC plasma stagnation signature of the more complex convection patterns during several positive/negative excursions of IMF Bz. Tue, 01 Jan 2008 00:00:00 GMT http://hdl.handle.net/2122/1865 Titolo: Results from Swedish oblique soundings campaigns<br/><br/>Autori: Broms, M.; National Defence Research Establishment, Linkoping, Sweden; Lundhorg, B.; Swedish Institute of Space Physics, Uppsala Division, Uppsala, Sweden<br/><br/>Abstract: In the context of the COST 238, PRIME project, two campaigns of oblique soundings with the Chirpsounder receiver at Linkoping, Sweden were made in parallel with vertical sounding campaigns. One campaign was made in June, 1992, when transmissions from Southern Spain were monitored, the other in December, 1992 when a transmitter at Chelveston, U.K, was monitored. The scaled values of F2MOF, 2-hop F2MOF and LOF give information on the variation of these parameters on short time scales and from day to day. High correlations between 2-hop F2MOF and F2MOF are found. Good agreement was found between the 2-hop MOF and MUF(1400)F2 calculated from vertical soundings at St. Peter Ording, Germany. Sun, 01 May 1994 00:00:00 GMT http://hdl.handle.net/2122/1695 Titolo: Mid-latitude ionosphere during two great geomagnetic storms<br/><br/>Autori: Vasiljevic, I. M.; Geomagnetic Institute, Grocka, Belgrade, Yugoslavia; Cander, L. R.; Geomagnetic Institute, Grocka, Belgrade, Yugoslavia<br/><br/>Abstract: The ionospheric disturbances observed at many European ionosonde stations in association with the severe geomagnetic storms occurring on 19-20 December 1980 and 11-12 April 1981 were investigated by using the available ionospheric and geomagnetic data. During these storms the ionospheric F region underwent major changes at all mid-latitudes. However, the variations from storm to storm were much larger at lower mid-latitudes. These results support the view that even in assessing the response of the mid-latitude ionosphere to severe geomagnetic storms it is necessary to distinguish carefully between global, regional and local behaviour. Thu, 01 Aug 1996 00:00:00 GMT http://hdl.handle.net/2122/1694 Titolo: Assessment of the solar-cycle dependence of f0F2 1157<br/><br/>Autori: Xenos, T. D.; Department of Electrical Engineering, University of Thessaloniki, Greece; Kouris, S. S.; Department of Electrical Engineering, University of Thessaloniki, Greece; Zolesi, B.; Istituto Nazionale di Geofisica, Roma, Italy<br/><br/>Abstract: Comparisons between observed hourly monthly-median values of f0F2 at Slough and Rome, and calculated f0F2 values using as an index of solar activity R12 or T12, demonstrate that there is practically no difference in the results when a solar (e.g., R12) or ionospheric index (e.g., T12) is used. The choice of the index should be based on other criteria. It is also shown that there is a slight degree of favourability for a quadratic law between f0F2 and each index of solar activity. Therefore, in mapping F-layer characteristics a second-degree relation should be adopted independently of rising or falling solar-cycle. Saturation and hysteresis effects could be then minimised. Sun, 01 Dec 1996 00:00:00 GMT http://hdl.handle.net/2122/1683 Titolo: Interplanetary magnetic field and its possible effects on the mid-latitude ionosphere III<br/><br/>Autori: Tulunay, Y.; Middle East Technical University, Department of Aeronautical Engineering, Ankara, Turkey<br/><br/>Abstract: Using critical frequencies, f0F2 from the Lannion, Slough, Poitiers, Garchy, Dourbes, Rome, Juliusrud, Gibilmanna, Pruhonice, Uppsala, Kaliningrad, Miedzeszyn, Sofia, Athens and Kiev ionosonde stations, the possible effects of the orientation of the Interplanetary Magnetic Field (IMF) on mid-latitude ionosphere are further investigated. This time, only the southward polarity changes in IMF Bz with seasonal effects were considered. The same method of analysis was employed to facilitate a comparison between the recent results presented here with those which appeared in the preceding papers in the series. That is, the regular diurnal, seasonal and solar cycle variations in the f0F2 data were removed by subtracting the mean of the f0F2 for the same UT on all magnetically quite days (Ap < 6) within 15 days around the IMF Bz turnings (Tulunay, 1994). This last paper also includes the seasonal effects on the ionospheric data. The results confirm that much of the day-to-day variability of the mid-latitude ionosphere may be related to the orientation of the southward IMF Bz , characterized by the ionospheric winter anomaly. Day-to-day ionospheric variability becomes more significant towards higher latitudes. Thu, 01 Aug 1996 00:00:00 GMT