Data issues in a moving environment: remote and in situ tools to monitor glacier dynamics and their hydrological consequences in the Austre Lovènbreen basin

• Main Authors: Tolle, Florian, Bernard, Eric, Friedt, Jean-Michel, Saintenoy, Albane, Marlin, Christelle, Griselin, Madeleine
• Other Authors: Théoriser et modéliser pour aménager (UMR 6049) (ThéMA), Université de Bourgogne (UB)-Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté COMUE (UBFC)-Université Bourgogne Franche-Comté COMUE (UBFC), Franche-Comté Électronique Mécanique, Thermique et Optique - Sciences et Technologies (UMR 6174) (FEMTO-ST), Université de Technologie de Belfort-Montbeliard (UTBM)-Ecole Nationale Supérieure de Mécanique et des Microtechniques (ENSMM)-Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC), Interactions et dynamique des environnements de surface (IDES), Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Géosciences Paris Sud (GEOPS), Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS)
• Format: Conference Object
• Language: English
• Published: HAL CCSD 2011
• Subjects: [SHS.GEO]Humanities and Social Sciences/Geography; glacier; IPY
• Online Access: https://hal.science/hal-00864532

COM International audience The precise quantification of glacier movements over time is one of the goals of glaciology. Understanding how and where ice is appearing, melting, and what happens once it’s gone are at the core of the Hydro - Se nsor - FlOWS program (IPY #16, IPEV 304, ANR 0310) that just ended and will be one of the aspects of the new Cryo - Sensors program. Obtaining a precise digital elevation model (DEM) of a glacier surface is not straightforward. When using old datasets, caution should be applied to the interpretation made of the results as the variability tends to increase. Recent monitoring techniques (DGPS, airborne Lidar) do provide a higher level of accuracy but still require a good knowledge of technology and its drawbacks, as well as field - specific issues (i.e. snow cover). Mass balance computations have been applied to Austre Lovénbreen using such techniques. When compared to ablation stakes measurements, results show striking differences, especially in accumulation areas. In areas where stakes do record accumulation, DEM differences account for ablation only. And the ablation measured using DEM seems greater than the vertical velocity of the glacier. Could it be possible that these two techniques do record processes occurr ing at the same time but at different scales? While stakes are measuring surface ice evolution only, DEM calculations are documenting the general trend of the glacier. It is possible that new ice is appearing in the upper cirques of the glacier while at th e scale of the basin, the glacier is in a global retreat trend. We are currently attempting to instrument the glacier in order to confirm our hypothesis and to quantify its extent. In an effort to precisely compute the volume of ice constituting today's gl acier, the surface DEM had to be complemented with a model of the bedrock on which the glacier is flowing. Ground Penetrating Radar (GPR) was used to get precise elevation values of the ice - rock interface. The difference between surface and bedrock DEM ...