http://hdl.handle.net/2122/109 Sat, 25 May 2013 18:42:31 GMT 2013-05-25T18:42:31Z http://hdl.handle.net/2122/7443 Title: Anomalies of oxygen measurements performed with Aanderaa optodes Authors: Lo Bue, Nadia; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia Editors: Làzaro, Antoni Mànuel; Technical University of Catalonia (UPC) Abstract: Four sets of measurements performed between 2005 and 2010 in the deep central Atlantic, and in deep Mediterranean Sea, and the Arctic Ocean revealed a strange performance of Aanderaa Optode 3830 sensors mounted on RCM11 current meters in low current regimes (current speeds > 10 cm s- 1) . All oxygen data sets collected during these deployments showed significant drops of oxygen (of the order of 50-100 ìmol/l) affecting the Optode data stability in low hydrodynamic conditions (fig.1). High correlations between all acquired parameters (i.e. temperature, turbidity, speed and direction of currents) allowed verifying that no unusual event perturbed the mooring areas during the periods of acquisition, although natural events responsible of so abrupt, short and intense oxygen variations can’t be easily found. Despite the well-known performance of the Aanderaa Optodes, these experiences suggested that the data acquired by optodes installed on RCM11s could not be always reliable, especially in low energy systems (typical for the deep ocean) and that current speeds should always be considered in order to verify the reliability of the data recorded. A series of test in controlled water condition was performed in order to better understand eventual sensor dependence on speed current variations and to evaluate sensor stability in quasi-stationary water. Wed, 21 Sep 2011 22:00:00 GMT http://hdl.handle.net/2122/7443 2011-09-21T22:00:00Z http://hdl.handle.net/2122/5119 Title: Geomagnetism and Aeronomy activities in Italy during IGY, 1957/58 Authors: Meloni, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Alfonsi, Lu.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia Abstract: 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. Tue, 31 Mar 2009 22:00:00 GMT http://hdl.handle.net/2122/5119 2009-03-31T22:00:00Z http://hdl.handle.net/2122/4886 Title: PEGASO: An ultra light long duration stratospheric payload for polar regions flights Authors: Iarocci, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia; Benedetti, P.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia; Caprara, F.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia; Cardillo, A.; Institute of Information Science and Technology, National Research Council, Via G. Moruzzi 1, 56124 Pisa, Italy; Di Felice, F.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia; Di Stefano, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia; Drakøy, P.; Andøya Rocket Range, Andenes, P.O. Box 54, N-8483 Andenes, Norway; Ibba, R.; Italian Space Agency, Luigi Broglio Launch Facility, ss. 113 n. 174, Contrada Milo, Trapani, Italy; Mari, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia; Musso, I.; Institute of Information Science and Technology, National Research Council, Via G. Moruzzi 1, 56124 Pisa, Italy; Palangio, P.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Peterzen, S.; Italian Space Agency, Luigi Broglio Launch Facility, ss. 113 n. 174, Contrada Milo, Trapani, Italy and International Science Technology and Research, Pagosa Springs, CO, USA; Romeo, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia; Spinelli, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia; Spoto, D.; Italian Space Agency, Luigi Broglio Launch Facility, ss. 113 n. 174, Contrada Milo, Trapani, Italy; Urbini, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia Abstract: Stratospheric balloons are powerful and affordable tools for a wide spectrum of scientific investigations that are carried out at the stratosphere level. They are less expensive compared to satellite projects and have the capability to lift payloads from a few kilograms to a couple of tons or more, well above the troposphere, for more than a month. Another interesting feature of these balloons, which is not viable in satellites, is the short turnaround time, which enables frequent flights. We introduce the PEGASO (Polar Explorer for Geomagnetism And other Scientific Observations) project, a stratospheric payload designed and developed by the INGV (Istituto Nazionale di Geofisica e Vulcanologia), Rome and La Sapienza University, Rome. The project was sponsored by the PNRA (Progetto Nazionale di Ricerche in Antartide), Italy (Peterzen et al., 2003). This light payload (10 kg) was used by the Italian Space Agency (ASI) and Andoya Rocket Range (ARR) for five different scientific missions. PEGASO carries a 3-component flux-gate magnetometer, uses a solar cell array as the power source and has a GPS location system. The bi-directional telemetry system for data transfer and the remote control system were IRIDIUM based. Sun, 16 Nov 2008 23:00:00 GMT http://hdl.handle.net/2122/4886 2008-11-16T23:00:00Z http://hdl.handle.net/2122/4736 Title: Comparative analysis of some magnetic sensors Authors: Gambetta, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Carmisciano, C.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Caratori Tontini, F.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Cocchi, L.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Muccini, F.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia Abstract: This paper shows the results of a comparative analysis of 5 magnetometer in order to evaluate the performance of the new Marine Magnetics SeaSPY Overhauser probe. The test was performed at INGV Geomagnetic Observatory in Preturo(L’Aquila, Italy). Both qualitative and quantitative analysis has been carried out. Mon, 31 Dec 2007 23:00:00 GMT http://hdl.handle.net/2122/4736 2007-12-31T23:00:00Z http://hdl.handle.net/2122/4267 Title: Last development in plate kinematics determination in Victoria Land (Antarctica) trough VLNDEF Network in Antarctica using Gamit/Globk software Authors: Capra, A.; DIMeC, Università di Modena e Reggio dell’Emilia; Casula, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Bologna, Bologna, Italia; Dubbini, M.; DIMeC, Università di Modena e Reggio dell’Emilia Abstract: Abstract A semi-permanent GPS network of about 30 vertices: Victoria Land Network for DEFormation control (VLNDEF) has been set up since Austral summer 1998 at Terra Nova Bay (TNB) near Ross Sea in Antarctica. A permanent GPS station TNB1 based on dual frequency Ashtech P-code GPS receiver with a Choke Ring Antenna has been installed on a bedrock monument in October 1998 and has recorded continuously up to the present. The GPS network has been routinely surveyed every two summers using high quality dual frequency GPS receivers; data, metadata and solutions are available to the scientific community at (http://www.geodant.unimore.it). In this paper we present the results of a distributed session approach applied to processing GPS data of the VLNDEF network, and based on Gamit/Globk 10.3 GPS analysis software. An improved reference frame definition was implemented using Globk package in order to compute Antarctic intra-plate residual velocities and to invert the strain field from GPS data in this region. Mon, 31 Dec 2007 23:00:00 GMT http://hdl.handle.net/2122/4267 2007-12-31T23:00:00Z http://hdl.handle.net/2122/3877 Title: Observatories in Italy Authors: Chiappini, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia Editors: Gubbins, D.; University of Leeds; Herrero-Bervera, E.; University of Hawaii at Manoa Abstract: Monitoring the Earth's magnetic field is carried out by geomagnetic observatories all over the world. In Italy, the first observatory was founded in 1880, when Pietro Tacchini, the director of the Central Meteorological Institute (Ufficio Centrale di Meteorologia), launched an initiative to study the distribution of the Earth's magnetic field over the Italian territory. Sun, 31 Dec 2006 23:00:00 GMT http://hdl.handle.net/2122/3877 2006-12-31T23:00:00Z http://hdl.handle.net/2122/3832 Title: PEGASO: An ultra light long duration stratospheric payload for polar regions flights Authors: Iarocci, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia; Benedetti, P.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia; Caprara, F.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia; Cardillo, A.; CNR, Italy; Di Felice, F.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia; Di Stefano, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia; Drakøy, P.; ARR, Norway; Ibba, R.; ASI, Italy; Mari, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia; Masi, S.; La Sapienza Unuversity, Rome, Italy; Musso, I.; CNR, Italy; Palangio, P.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Peterzen, S.; istar, USA; Romeo, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia; Spinelli, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia; Spoto, D.; ASI, Italy; Urbini, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia Abstract: Stratospheric balloons are powerful and affordable tools for a wide spectrum of scientific investigations that are carried out at the stratosphere level. They are less expensive compared to satellite projects and have the capability to lift payloads from a few kilograms to a couple of tons or more, well above the troposphere, for more than a month. Another interesting feature of these balloons, which is not viable in satellites, is the short turnaround time, which enables frequent flights. We introduce the PEGASO (Polar Explorer for Geomagnetism And other Scientific Observations) project, a stratospheric payload designed and developed by the INGV (Istituto Nazionale di Geofisica e Vulcanologia), Rome and La Sapienza University, Rome. The project was sponsored by the PNRA (Progetto Nazionale di Ricerche in Antartide), Italy (Peterzen et al., 2003). This light payload (10 kg) was used by the Italian Space Agency (ASI) and Andoya Rocket Range (ARR) for five different scientific missions. PEGASO carries a 3-component flux-gate magnetometer, uses a solar cell array as the power source and has a GPS location system. The bi-directional telemetry system for data transfer and the remote control system were IRIDIUM based Sat, 31 Dec 2005 23:00:00 GMT http://hdl.handle.net/2122/3832 2005-12-31T23:00:00Z http://hdl.handle.net/2122/3669 Title: MIRTO: a prototype for real-time ionospheric imaging over the Mediterranean area Authors: Alfonsi, Lu.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Mitchell, C. N.; Department of Electronic and Electrical Engineering, University of Bath, U. K.; Romano, V.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Spalla, P.; Istituto di Fisica Applicata "Nello Carrara" (IFAC), CNR, Sesto Fiorentino (FI), Italy Abstract: 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. Thu, 31 May 2007 22:00:00 GMT http://hdl.handle.net/2122/3669 2007-05-31T22:00:00Z http://hdl.handle.net/2122/3515 Title: Rapid neuronet inversion of 2D magnetotelluric data for monitoring of geoelectrical section parameters Authors: Shimelevich, M. I.; Moscow State Geoprospecting University, Moscow, Russia; Obornev, M. A.; Moscow State Geoprospecting University, Moscow, Russia; Gavryushov, S.; Engelhardt Institute of Molecular Biology, Moscow, Russia Abstract: The inverse MagnetoTelluric (MT) operator is approximated by means of the Neural Network (NN). The methodology of the NN interpretation in classes of the geoelectrical sections described by the hundreds of parameters is proposed. Error of the NN inversion and field misfit are evaluated. A rapid NN algorithm solving the inverse problem and detecting changes of time-dependent dynamic parameters of the section is applied to 2D synthetic data. Wed, 31 Jan 2007 23:00:00 GMT http://hdl.handle.net/2122/3515 2007-01-31T23:00:00Z http://hdl.handle.net/2122/3509 Title: Stochastic interpretation of magnetotelluric data, comparison of methods Authors: Cerv, V.; Geophysical Institute, Academy of Sciences of the Czech Republic, Prague 4, Czech Republic; Menvielle, M.; Centre d’Études des Environnements Terrestre et Planétaire, Saint Maur des Fosses Cedex, France; Pek, J.; Geophysical Institute, Academy of Sciences of the Czech Republic, Prague 4, Czech Republic Abstract: Global optimization and stochastic approaches to the interpretation of measured data have recently gained particular attraction as tools for directed search for and/or verification of characteristic structural details and quantitative parameters of the deep structure, which is a task often arising when interpreting geoelectrical induction data in seismoactive and volcanic areas. We present a comparison of three common global optimization and stochastic approaches to the solution of a magnetotelluric inverse problem for thick layer structures, specifically the controlled random search algorithm, the stochastic sampling by the Monte Carlo method with Markov chains and its newly suggested approximate, but largely accelerated, version, the neighbourhood algorithm. We test the algorithms on a notoriously difficult synthetic 5-layer structure with two conductors situated at different depths, as well as on the experimental COPROD1 data set standardly used to benchmark 1D magnetotelluric inversion codes. The controlled random search algorithm is a fast and reliable global minimization procedure if a relatively small number of parameters is involved and a search for a single target minimum is the main objective of the inversion. By repeated runs with different starting test model pools, a sufficiently exhaustive mapping of the parameter space can be accomplished. The Markov chain Monte Carlo gives the most complete information for the parameter estimation and their uncertainty assessment by providing samples from the posterior probability distribution of the model parameters conditioned on the experimental data. Though computationally intensive, this method shows good performance provided the model parameters are sufficiently decorrelated. For layered models with mixed resistivities and layer thicknesses, where strong correlations occur and even different model classes may conform to the target function, the method often converges poorly and even very long chains do not guarantee fair distributions of the model parameters according to their probability densities. The neighbourhood resampling procedure attempts to accelerate the Monte Carlo simulation by approximating the computationally expensive true target function by a simpler, piecewise constant interpolant on a Voronoi mesh constructed over a set of pre-generated models. The method performs relatively fast but seems to suggest systematically larger uncertainties for the model parameters. The results of the stochastic simulations are compared with the standard linearized solutions both for thick layer models and for smooth Occam solutions. Wed, 31 Jan 2007 23:00:00 GMT http://hdl.handle.net/2122/3509 2007-01-31T23:00:00Z