GNGTS 2019 - Atti del 38° Convegno Nazionale

714 GNGTS 2019 S essione 3.2 the glacier where the snowpack is thinner and preventing the cooling where the snowpack is thicker. Warm ice zones on the 2015 GPR profiles are located in the areas where the snowpack is higher than about 5 m (FIG.3d) further corroborating the previous interpretation. On the contrary, where the snow cover is less thick, or does even not exist, the survey highlighted the presence of cold ice. Conclusions This work proves that GPR is an extremely useful technique to estimate the volume of glaciers and the total water stored within them. We determined a negative mass balance of the Marmolada Glacier within the 2004-2014 period, equal to -4.7 m w.e., and a corresponding decrease of the ice volume by about 30%, with a fragmentation of the previously single glacier into separated ice bodies. In addition, GPR proved its applicability in the characterization of different frozen materials as demonstrated by the identification of coexisting cold-warm ice portions. Attribute analysis is essential to corroborate such an interpretation, magnifying the different EM signature of frozen materials containing various amounts of free water. Future researches will focus on the quantification of free water and its changes in both time and space. Evidences of the coexistence of cold and warm ice on an alpine glacier imaged by GPR, on our best knowledge, are indeed scarce in the literature and this work provides one of the few existing examples in the Alps. References Carton, A., Bondesan, A., Benetton, S., 2017. Marmolada, la regina delle Dolomiti, Itinerari Glaciologici sulle Montagne Italiane 3 . Itinerari 19A e 19B, 189-212 (in Italian). Carturan, L., Baroni, C., Becker, M., Bellin, A., Cainelli, O., Carton, A., Casarotto, C., Dalla Fontana, G., Godio, A., Martinelli, T., Salvatore, M.C., Seppi, R., 2013. Decay of a long-term monitored glacier: Careser Glacier (Ortles- Cevedale, European Alps) . The Cryosphere, 7, 1819-1838. Crepaz, A., Cagnati, A., De Luca, G., 2013. Evoluzione dei ghiacciai delle Dolomiti negli ultimi cento anni e recenti bilanci di massa in tre apparati glaciali . Neve e Valanghe, 80 (in Italian). Del Gobbo, C., Colucci, R.R., Forte, E., Triglav Cekada, M., Zorn, M., 2016. The Triglav Glacier (South-Eastern Alps, Slovenia): Volume estimation, internal characterization and 2000-2013 temporal evolution by means of GPR measurements . Pure and Applied Geophysics, 173, 2753-2766. Diolaiuti, G., Smiraglia, C., Pelfini, M., Belò, M., Pavan, M., Vassena, G., 2006. The recent evolution of an alpine glacier used for summer skiing (Vedretta Piana, Stelvio Pass, Italy) . Cold Regions Science and Technology, 44, 206-216. Forte, E., Basso Bondini, M., Bortoletto, A., Dossi, M., Colucci, R.R., 2019. Pros and cons in helicopter-borne GPR data acquisition on rugged mountainous areas: critical analysis and practical guidelines . Pure and Applied Geophysics, 1-22, 10.1007/s00024-019-02196-2. Guglielmin, M., 2004. Observations on permafrost ground thermal regimes from Antarctica and the Italian Alps and their relevance to global climate change. Global and Planetary Change, 40, 159-167. Pettersson, P., Jansson, P., Blatter, H., 2004. Spatial variability in water content at the cold-temperate transition surface of the polythermal Storgläciaren, Sweden . Journal of Geophysical Research, 109. Haeberli, W., Huggel, C., Paul, F., Zemp, M., 2013. Glacial Responses to Climate Change . Treatise on Geomorphology, 13, 152-175. Santin, I., Colucci, R.R., Žebre, M., Pavan, M., Cagnati, A., Forte, E., 2019. Recent evolution of Marmolada glacier (Dolomites, Italy) by means of ground and airborne GPR surveys . Remote Sensing of Environment. Special issue on Integration of Space and in-Situ techniques: a new Paradigm for the Monitoring and Surveillance, accepted, in press. Zemp, M., Thibert, E., Huss, M., Stumm, D., Rolstad Denby, C., Nuth, C., Nussbaumer, S.U., Moholdt, G., Mercer, A., Mayer, C., Joerg, P.C., Jansson, P., Hynek, B., Fischer, A., Escher-Vetter, H., Elvehøy, H., Andreassen, L.M., 2013. Reanalysing glacier mass balance measurement series . The Cryosphere, 7, 1227-1245.