DSpace Community: 02.02. Glaciers

Analysis of bottom morphology of the David Glacier-Drygalski Ice Tongue, East Antarctica

Fri, 29 Oct 1999 22:58:59 GMT

Title: Analysis of bottom morphology of the David Glacier-Drygalski Ice Tongue, East Antarctica

Authors: Tabacco, I. E.; Sezione Geofisica, Dipartimento di Science della Terra, Università degli Studi di Milano, I-20129 Milano, Italy; Bianchi, C.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Chiappini, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Zirizzotti, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Zuccheretti, E.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia

Abstract: 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.

Analysis of bottom morphology of the David Glacier-Drygalski Ice Tongue, East Antarctica

Fri, 29 Oct 1999 22:58:59 GMT

Analysis of bottom morphology of the David Glacier-Drygalski Ice Tongue, East Antarctica

Fri, 29 Oct 1999 22:58:59 GMT

Snow dunes and glazed surfaces in Antarctica: new field and remote-sensing data

Mon, 29 Oct 2001 22:58:59 GMT

Title: Snow dunes and glazed surfaces in Antarctica: new field and remote-sensing data

Authors: Frezzotti, M.; ENEA, Centro Ricerche Casaccia, P.O. Box 2400, I-00100 Rome, Italy; Gandolfi, S.; DISTART, Università di Bologna, Viale Risorgimento 2, I-40136 Bologna, Italy; La Marca, F.; Dipartimento di ICMMPM, Università di Roma "La Sapienza", Via Eudossiana 18, I-00184 Rome, Italy; Urbini, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia

Abstract: As part of the International Trans-Antarctic Scientific Expedition project, the Italian Antarctic Programme undertook two traverses from the Terra Nova station to Talos Dome and to Dome C. Along the traverses, the party carried out several tasks (drilling, glaciological and geophysical exploration). The difference in spectral response between glazed surfaces and snow makes it simple to identify these areas on visible/near-infrared satellite images. Integration of field observation and remotely sensed data allows the description of different mega-morphologic features: wide glazed surfaces, sastrugy glazed surface fields, transverse dunes and megadunes. Topography global positioning system, ground penetrating radar and detailed snow-surface surveys have been carried out, providing new information about the formation and evolution of mega-morphologic features. The extensive presence, (up to 30%) of glazed surface caused by a long hiatus in accumulation, with an accumulation rate of nil or slightly negative, has a significant impact on the surface mass balance of a wide area of the interior part of East Antarctica. The aeolian processes creating these features have important implications for the selection of optimum sites for ice coring, because orographic variations of even a few metres per kilometre have a significant impact on the snow-accumulation process. Remote-sensing surveys of aeolian macro-morphology provide a proven, high-quality method for detailed mapping of the interior of the ice sheet's prevalent wind direction and could provide a relative indication of wind intensity.