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Testut, L.
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Testut, L.
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- PublicationRestrictedInfluence of geometrical boundary conditions on the estimation of rheological parameters(2000)
; ; ; ; ;Testut, L.; UMR5566, Groupe de Recherche de Géodésie Spatiale, CNES-CNRS, Toulouse Cedex 31055, France ;Tabacco, I. E.; Dipartimento di Scienze della Terra, Università degli Studi di Milano, I-20129 Milan, Italy ;Bianchi, C.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia ;Rémy, F.; UMR5566, Groupe de Recherche de Géodésie Spatiale, CNES-CNRS, Toulouse Cedex 31055, France; ; ; Improved knowledge of geometrical boundary conditions, such as bedrock geometry and surface topography, can contribute significantly to glaciological studies including ice-sheet-flow modelling. Precise thickness and altimetric data allow an estimation of ice-flow direction, the balance velocity and the basal shear stress. These parameters are calculated along a 1160 km profile in East Antarctica using a relationship between shear stress, basal temperature, the Glen flow exponent and a parameter related to strain rate. Strong variations of the flow-law parameters and basal conditions are found to play a major role in the ice-flow pattern. Sliding, anisotropy and longitudinal stress strongly perturb the validity of the law, but their signature can be identified.463 62 - PublicationRestrictedLakes and subglacial hydrological networks around Dome C, East Antarctica(2003)
; ; ; ; ; ; ;Rémy, F.; Laboratoire d’Etudes en Géophysique et Océanographie Spatiale, 18 avenue Edouard Belin, 31055 Toulouse Cedex, France ;Testut, L.; Laboratoire d’Etudes en Géophysique et Océanographie Spatiale, 18 avenue Edouard Belin, 31055 Toulouse Cedex, France ;Legrésy, B.; Laboratoire d’Etudes en Géophysique et Océanographie Spatiale, 18 avenue Edouard Belin, 31055 Toulouse Cedex, France ;Forieri, A.; Dipartimento di Scienze della Terra, Università degli Studi di Milano, Via Cicognara 7, I-20129 Milan, Italy ;Bianchi, C.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia ;Tabacco, I. E.; Dipartimento di Scienze della Terra, Università degli Studi di Milano, Via Cicognara 7, I-20129 Milan, Italy; ; ; ; ; Precise topography from European Remote-sensing Satellite radar altimetry and high density of airborne radio-echo sounding in the area surrounding Dome C, Antarctica, show a link between surface features and subglacial lakes. In this paper, we extend the study to fine structures by computing a curvature-based coefficient (cy) related to surface undulations. These coefficient variations reveal many surface undulations, and some elongated features of this parameter seem to link known subglacial lakes. A population of high values of this coefficient, assumed to correspond to transitions between sliding and non-sliding flow regime, strengthen the appearance of a network which would link most of the lakes in the area. The existence of such a network impacts on ice-flow dynamics and on subglacial-lake studies.510 103