285 research outputs found

    Radio Echo Sounding (RES) investigations at Talos Dome (East Antarctica): bedrock topography and ice thickness

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    Radio echo sounding measurements were collected during two Antarctic expeditions to determine the ice thickness and the sub-glacial morphology of Talos Dome in the region around 72°48'S; 159°06'E (about 6400 km2) on the edge of the East Antarctic plateau adjacent to Victoria Land in the western Ross Sea sector. The increasing interest in this region is due to the fact that in this area the ice accumulation is higher than in other sites in East Antarctica. Because of this, Talos Dome could be a new site for a project of a deep ice core drilling to obtain information on climate changes near the coast of Antarctica. In this frame, the knowledge of the bedrock topography is of great importance to choose the best location for the drilling site. In this paper, airborne radio echo sounding results from two Antarctic expeditions (1997 and 1999) are presented. Bedrock topography in bi- and three-dimensions for the Talos Dome region are discussed

    On the origin of intermittency in wave turbulence

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    Using standard signal processing tools, we experimentally report that intermittency of wave turbulence on the surface of a fluid occurs even when two typical large-scale coherent structures (gravity wave breakings and bursts of capillary waves on steep gravity waves) are not taken into account. We also show that intermittency depends on the power injected into the waves. The dependence of the power-law exponent of the gravity-wave spectrum on the forcing amplitude cannot be also ascribed to these coherent structures. Statistics of these both events are studied.Comment: To be published in EP

    The ISIS Project: Indications for Future Near-Earth Plasma Studies through Future Galileo Satellites

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    The Earth’s plasmasphere variability is a consequence of the Sun’s forcing, determining our planet’s space weather. Plasmaspheric dynamics could be entirely caught only by studying together global and local proxies of the state of this extended system. The ISIS project (Inter-Satellite & In Situ plasmaspheric monitoring and modelling) aimed to design a system for the continuous monitoring of the Earth’s plasmasphere based on the future Galileo satellites. The efforts and expertise of ISC-CNR (Institute for Complex Systems of the National Research Council of Italy), INGV (Istituto Nazionale di Geofisica e Vulcanologia) and TAS-I (Thales Alenia Space - Italy) were put together in this work of assessment. ISIS Team proposed new experimental facilities of the Galileo satellites, designed to realize inter-satellite and in situ measurements to monitor global and local quantities; in particular, a scalable system of Langmuir probes was suggested, while the TEC along all possible inter-satellite ray paths throughout the plasmasphere could be monitored via phase- and group-delay analysis of inter-satellite radio signals

    ANNALS OF GEOPHYSICS: AD MAJORA

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    Annals of Geophysics (ISSN: 1593-5213; from 2010, 2037-416X) is a bimonthly international journal, which publishes scientific papers in the field of geophysics sensu lato. It derives from Annali di Geofisica (ISSN: 0365-2556), which commenced publication in January 1948 as a quarterly periodical devoted to general geophysics, seismology, Earth magnetism, and atmospheric studies...

    The ISIS Project: Indications for Future Near-Earth Plasma Studies through Future Galileo Satellites

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    The Earth’s plasmasphere variability is a consequence of the Sun’s forcing, determining our planet’s space weather. Plasmaspheric dynamics could be entirely caught only by studying together global and local proxies of the state of this extended system. The ISIS project (Inter-Satellite & In Situ plasmaspheric monitoring and modelling) aimed to design a system for the continuous monitoring of the Earth’s plasmasphere based on the future Galileo satellites. The efforts and expertise of ISC-CNR (Institute for Complex Systems of the National Research Council of Italy), INGV (Istituto Nazionale di Geofisica e Vulcanologia) and TAS-I (Thales Alenia Space - Italy) were put together in this work of assessment. ISIS Team proposed new experimental facilities of the Galileo satellites, designed to realize inter-satellite and in situ measurements to monitor global and local quantities; in particular, a scalable system of Langmuir probes was suggested, while the TEC along all possible inter-satellite ray paths throughout the plasmasphere could be monitored via phase- and group-delay analysis of inter-satellite radio signals.Published1A. Geomagnetismo e Paleomagnetismo2A. Fisica dell'alta atmosferaN/A or not JCRope

    The ISIS Project: Indications for Future Near-Earth Plasma Studies through Future Galileo Satellites

    Get PDF
    The Earth’s plasmasphere variability is a consequence of the Sun’s forcing, determining our planet’s space weather. Plasmaspheric dynamics could be entirely caught only by studying together global and local proxies of the state of this extended system. The ISIS project (Inter-Satellite & In Situ plasmaspheric monitoring and modelling) aimed to design a system for the continuous monitoring of the Earth’s plasmasphere based on the future Galileo satellites. The efforts and expertise of ISC-CNR (Institute for Complex Systems of the National Research Council of Italy), INGV (Istituto Nazionale di Geofisica e Vulcanologia) and TAS-I (Thales Alenia Space - Italy) were put together in this work of assessment. ISIS Team proposed new experimental facilities of the Galileo satellites, designed to realize inter-satellite and in situ measurements to monitor global and local quantities; in particular, a scalable system of Langmuir probes was suggested, while the TEC along all possible inter-satellite ray paths throughout the plasmasphere could be monitored via phase- and group-delay analysis of inter-satellite radio signals

    Geophysical survey at Talos Dome, East Antarctica: the search for a new deep-drilling site

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    Talos Dome is an ice dome on the edge of the East Antarctic plateau; because accumulation is higher here than in other domes of East Antarctica, the ice preserves a good geochemical and palaeoclimatic record. A new map of the Talos Dome area locates the dome summit using the global positioning system (GPS) (72˚47’ 14’’S, 159˚04’ 2’’E; 2318.5m elevation (WGS84)). A surface strain network of nine stakes was measured using GPS. Data indicate that the stake closest to the summit moves south-southeast at a few cma–1. The other stakes, located 8 km away, move up to 0.33ma–1. Airborne radar measurements indicate that the bedrock at the Talos Dome summit is about 400m in elevation, and that it is covered by about 1900m of ice. Snow radar and GPS surveys show that internal layering is continuous and horizontal in the summit area (15 km radius). The depth distribution analysis of snow radar layers reveals that accumulation decreases downwind of the dome (north-northeast) and increases upwind (south-southwest). The palaeomorphology of the dome has changed during the past 500 years, probably due to variation in spatial distribution of snow accumulation, driven by wind sublimation. In order to calculate a preliminary age vs depth profile for Talos Dome, a simple one-dimensional steady-state model was formulated. This model predicts that the ice 100m above the bedrock may cover one glacial–interglacial period.Published423-4323.8. Geofisica per l'ambienteJCR Journalreserve

    Reversals in nature and the nature of reversals

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    The asymmetric shape of reversals of the Earth's magnetic field indicates a possible connection with relaxation oscillations as they were early discussed by van der Pol. A simple mean-field dynamo model with a spherically symmetric α\alpha coefficient is analysed with view on this similarity, and a comparison of the time series and the phase space trajectories with those of paleomagnetic measurements is carried out. For highly supercritical dynamos a very good agreement with the data is achieved. Deviations of numerical reversal sequences from Poisson statistics are analysed and compared with paleomagnetic data. The role of the inner core is discussed in a spectral theoretical context and arguments and numerical evidence is compiled that the growth of the inner core might be important for the long term changes of the reversal rate and the occurrence of superchrons.Comment: 24 pages, 12 figure

    New energy geographies : a case study of yoga, meditation and healthfulness

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    Beginning with a routine day in the life of a practitioner of yoga and meditation and emphasising the importance of nurturing, maintaining and preventing the dissipation of diverse ‘energies’, this paper explores the possibilities for geographical health studies which take seriously ‘new energy geographies’. It is explained how this account is derived from in-depth fieldwork tracing how practitioners of yoga and meditation find times and spaces for these practices, often in the face of busy urban lifestyles. Attention is paid to the ‘energy talk’ featuring heavily in how practitioners describe the benefits that they perceive themselves to derive from these practices, and to claims made about ‘energies’ generated during the time-spaces of these practices which seemingly flow, usually with positive effects, into other domains of their lives. The paper then discusses the implications of this energy talk in the context of: (a) critically reviewing conventional approaches to studying ‘energy geographies’; (b) identifying an alertness to the likes of ‘affective energies’ surfacing in recent theoretically-attuned works of human geography (and cognate disciplines); and (c) exploring differing understandings of energy/energies extant in geographical studies of health and in step with the empirical research materials presented about yoga, meditation and healthfulness. While orientated towards explicitly geographical inquiries, the paper is intended as a statement of interest to the wider medical humanities
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