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  • Antarctica  (4)
  • 02. Cryosphere::02.02. Glaciers::02.02.07. Ocean/ice interaction  (2)
  • International Glaciological Society  (4)
  • Copernicus  (1)
  • EGU General Assembly 2011 © Author(s) 2011  (1)
  • American Physical Society
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Years
  • 1
    Publication Date: 2023-04-26
    Description: Persistent katabatic winds form widely distributed localized areas of near-zero net surface accumulation on the East Antarctic ice sheet (EAIS) plateau. These areas have been called ‘glaze’ surfaces due to their polished appearance. They are typically 2–200km2 in area and are found on leeward slopes of ice-sheet undulations and megadunes. Adjacent, leeward high-accumulation regions (isolated dunes) are generally smaller and do not compensate for the local low in surface mass balance (SMB). We use a combination of satellite remote sensing and field-gathered datasets to map the extent of wind glaze in the EAIS above 1500m elevation. Mapping criteria are derived from distinctive surface and subsurface characteristics of glaze areas resulting from many years of intense annual temperature cycling without significant burial. Our results show that 11.2 1.7%, or 950 143 103 km2, of the EAIS above 1500m is wind glaze. Studies of SMB interpolate values across glaze regions, leading to overestimates of net mass input. Using our derived wind-glaze extent, we estimate this excess in three recent models of Antarctic SMB at 46–82 Gt. The lowest-input model appears to best match the mean in regions of extensive wind glaze.
    Description: Published
    Description: 633-647
    Description: 3.8. Geofisica per l'ambiente
    Description: JCR Journal
    Description: restricted
    Keywords: Antarctica ; snow accumulation ; Surface Mass Balance ; 02. Cryosphere::02.02. Glaciers::02.02.99. General or miscellaneous ; 02. Cryosphere::02.02. Glaciers::02.02.02. Cryosphere/atmosphere Interaction ; 02. Cryosphere::02.02. Glaciers::02.02.06. Mass balance
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 2
    Publication Date: 2017-04-04
    Description: During the 2007-2008 antarctic campaign, the Italian PNRA installed a Low Power Magnetometer within the framework of the AIMNet (Antarctic International Magnetometer Network) project, proposed and coordinated by BAS. The magnetometer is situated at Talos Dome, around 300 km geographically North-West from Mario Zucchelli Station (MZS), and approximately at the same geomagnetic latitude as MZS. In this work we present a preliminary analysis of the geomagnetic field 1-min data, and a comparison with simultaneous data from different Antarctic stations.
    Description: Published
    Description: Vienna, Austria
    Description: 1.6. Osservazioni di geomagnetismo
    Description: open
    Keywords: daily variation ; AIMNet project ; Antarctica ; 04. Solid Earth::04.05. Geomagnetism::04.05.02. Geomagnetic field variations and reversals
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: Poster session
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  • 3
    Publication Date: 2017-04-04
    Description: Data from radio-sounding measurements have been analysed to determine the ice thickness and the bottom morphology of Drygalski Ice Tongue, Antarctica. The morphology and the structure of the bottom surface has been studied through an electromagnetic interpretation. A function that includes the gain/loss due to the geometrical shape of the reflecting surfaces has been calculated. Such a function has been evaluated assuming some physical electromagnetic quantities (the temperature of the glacier, the complex dielectric permittivity of ice, sea ice and sea water). The ice-water interface shows both concave and convex faces toward the sounding system, producing a focusing or defocusing effect, detected as absolute (or relative) amplitude variation in the echo signal. It is shown that the calculated function follows quite well the observed bottom rippled surface of the glacier tongue estimated from the time-arrival measurements of the echo signal.
    Description: Published
    Description: 47-51
    Description: 3.8. Geofisica per l'ambiente
    Description: JCR Journal
    Description: reserved
    Keywords: glaciers ; radio-echo-sounding ; radio propagation in the ice ; 02. Cryosphere::02.02. Glaciers::02.02.99. General or miscellaneous ; 02. Cryosphere::02.02. Glaciers::02.02.07. Ocean/ice interaction ; 02. Cryosphere::02.02. Glaciers::02.02.10. Instruments and techniques
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 4
    Publication Date: 2020-02-24
    Description: Eastern Dome C, southern Talos Dome and northern Taylor Dome are drained by the Priestley, Reeves, David, Mawson and Mackay outlet glaciers, which flow into the Scott Coast on the west side of the Ross Sea, Antarctica. Airborne radar surveys were conducted on these glaciers to determine ice thickness and bed morphology along transverse and longitudinal profiles of the grounded and floating segments. A new analysis of a Landsat Thematic Mapper satellite image using a tracking technique was used to measure ice velocity at grounding lines and along ice tongues. The integration of radar and satellite data helped to locate grounding lines and to calculate the ice discharge. Changes in ice fluxes of floating glaciers were used to determine basal melting and freezing rates. The ice discharge calculated is less than half that required for a zero net surface mass balance according to the inputs given by the accumulation estimates widely adopted at present. The basal melting rates of meteoric ice represent 50% of the net ablation rate.
    Description: Published
    Description: 253-264
    Description: 3.8. Geofisica per l'ambiente
    Description: JCR Journal
    Description: open
    Keywords: Mass balance ; Antarctica ; 02. Cryosphere::02.02. Glaciers::02.02.06. Mass balance
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 5
    Publication Date: 2017-04-04
    Description: With mass loss from the Greenland ice sheet accelerating and spreading to higher latitudes, the quantification of mass discharge in the form of icebergs has recently received much scientific attention. Here, we make use of very low frequency (0.001-0.01 Hz) seismic data from three permanent broadband stations installed in the summers of 2009/2010 in northwest Greenland in order to monitor local calving activity. At these frequencies, calving seismograms are dominated by a tilt signal produced by local ground flexure in response to fjord seiching generated by major iceberg calving events. A simple triggering algorithm is proposed to detect calving events from large calving fronts with potentially no user interaction. Our calving catalogue identifies spatial and temporal differences in calving activity between Jakobshavn Isbræ and glaciers in the Uummannaq district some 200 km further north. The Uummannaq glaciers show clear seasonal fluctuations in seiche-based calving detections as well as seiche amplitudes. In contrast, the detections at Jakobshavn Isbræ show little seasonal variation, which may be evidence for an ongoing transition into winter calving activity. The results offer further evidence that seismometers can provide efficient and inexpensive monitoring of calving fronts.
    Description: Published
    Description: 162-178
    Description: 1.8. Osservazioni di geofisica ambientale
    Description: JCR Journal
    Description: restricted
    Keywords: icequakes ; calving icebergs ; Greenland ; 02. Cryosphere::02.02. Glaciers::02.02.07. Ocean/ice interaction ; 02. Cryosphere::02.02. Glaciers::02.02.10. Instruments and techniques ; 04. Solid Earth::04.02. Exploration geophysics::04.02.06. Seismic methods ; 04. Solid Earth::04.06. Seismology::04.06.06. Surveys, measurements, and monitoring
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 6
    Publication Date: 2017-04-04
    Description: A Global Positioning System (GPS) network of 30 semi-permanent vertices known as the Victoria Land Network for Deformation Control (VLNDEF) was set up in the Austral summer of 1998 in Northern Victoria Land (NVL), including the permanent GPS station of Terra Nova Bay (TNB1), Antarctica. The locations were selected according to the known Cenozoic fault framework, which is characterized by a system of NW[U+2010]SE regional faults with right[U+2010]lateral, strike[U+2010]slip kinematics. The TNB1 permanent GPS station is included within the VLNDEF, and was installed on a bedrock monument in October 1998, it has been recording almost continuously up to the present. The GPS network has been surveyed routinely every two summers, using high[U+2010]quality, dual[U+2010]frequency GPS receivers like Trimble 5700, TopCon GB100, and Ashtech Z-XII. In this study we present the results of a distributed session approach based on Gamit/Globk 10.4 software package applied to the processing of the GPS data of the VLNDEF aimed to obtain the preliminary framework of the active tectonics of this region of Antarctica. An improved reference frame definition was implemented, including a new Euler rotation pole, to compute the Antarctic intra-plate residual velocities. The projection of the residual velocities on the main faults in NVL show present[U+2010]day activities for some faults, including the Tucker, Leap Year, Lanterman, Aviator, and David faults, with right[U+2010]lateral strike[U+2010]slip kinematics and local extensional and compressional components. This active fault pattern divides NVL into eight rigid blocks, each characterized by its relative movements and rigid rotations. These show velocities of up to several millimeters per year, which are comparable to those predicted by plate tectonic theory at active plate margins. During the austral summer 2010, in the framework of the Italian Antarctic campaign, field investigations at 25 geodetic stations were performed both for survey of the instruments and measurements as well as for the geological study necessary to evaluate the geological stability of the sites. Preliminary analysis of the collected structural data showed the stability of most of the investigated stations, thus confirming the proposed active tectonic framework of the NVL at the regional scale.
    Description: Published
    Description: Vienna, Austria 3–8 April 2011
    Description: 3.2. Tettonica attiva
    Description: reserved
    Keywords: Antarctica ; Northern Victoria Land ; Active Tectonics ; GPS data ; Geologic Setting ; 04. Solid Earth::04.07. Tectonophysics::04.07.04. Plate boundaries, motion, and tectonics
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: Abstract
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