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Item Initial reconnaissance for a South Georgia ice core(Cambridge Universty Press, 2016-03-16) Mayewsky, P.A.; Kuli, A.; Casassa, Gino; Arévalo, M.; Dixon, D.A.; Grigholm, B.; Handley, M.J.; Hoffmann, H.; Introne, D.S.; Kuli, A.G.; Potocki, M.; Sneed, S.B.We present the first snow/ice chemistry and ice radar results ever collected from South Georgia as part of an initial reconnaissance with the ultimate goal of assessing the feasibility of a South Georgia ice core to reconstruct past climate in the South Atlantic. South Georgia is well situated to capture a record of past atmospheric chemical composition over the South Atlantic and of past variability in the position and intensity of the austral westerlies. The question is how well preserved an ice core record can be recovered from a region experiencing accelerated melting? The results presented in this paper offer only a preliminary step in determining the feasibility of future deep ice coring on South Georgia. However, this initial reconnaissance does provide some basic information including: the chemistry of the atmosphere over South Georgia relative to other Southern Hemisphere ice coring sites; the potential for preservation of ‘annual layers’ in old ice on the island; a possible age for deep ice in the region; and an estimate of glacier health in the lower elevation regions of the island.Item Boletín Antártico Chileno(2003-05) Berguño Barnes, Jorge; Hervé, Francisco; Lacassie, Juan Pablo; Fernández, Rodrigo; Morata, Diego; Durán, Mauricio; Oteíza, Orlando; Solari, Marcelo; Cordaro, Enrique; Olivares, Enrique; Vallejos, Verónica; Vargas, Romeo; Osman, Layla; Vera, Claudio; Torres, Daniel; Oyarzún, Jorge; Vicuña, Patricia; Guzmán, Eugenio; Pérez García, Héctor; Acuña, César; Casassa, Gino; Couyoumdjian, Hernán; Rivera Ibáñez, Andrés; Sinclair, Rolf; Teitelboim, Claudio; Abdalati, Waleed; Krabile, William; Frederick, Earl; Manizade, Serdar; Russell, Robert; Sonntag, John; Swift, Robert; Thomas, Robert; Yungel, James; Akins, Torry; Gogineni, Sivaprasad; Kanagaratnam, Pannirselvam; Rignot, Eric; Valencia, José; Instituto Antártico Chileno; Ordóñez Kovacevic, Yasna; Berguño Barnes, Jorge; Ríos Villalón, Juan; Torres, DanielItem Historically unprecedented global glacier decline in the early 21st century(International Glaciological Society, 2015) Zemp, Michael; Frey, Holger; Garnert-Roer, Isabelle; Nussbaumer, Samuel U.; Hoelzle, Martin; Paul, Frank; Haeberli, Wilfried; Denzinger, Florian; Anderson, Brian; Bajracharya, Samjwal; Baroni, Carlo; Braun, Ludwing N.; Cáceres, Bolívar E.; Casassa, Gino; Dávila, Luzmila R.; Delgado Granados, Hugo; Demuth, Michael N.; Espizua, Lydia; Fisher, Andrea; Fujita, Koji; Gadek, Bogdan; Ghazanfar, Ali; Hagen, Jon Ovi; Holmlund, Per; Karimi, Neamat; Li, Zhonqin; Pelto, Mauri; Pitte, Pierre; Popovnin, Victor V.; Portocarrero, Cesar A.; Prinz, Rainer; Sangewar, Chandrashekhar; Severskiy, Igor; Sigurdsson, Oddur; Soruco, Alvaro; Usubaliev, Ryskul; Vincent, Christian; Ahlstrom, Andreas P.; Cobos, GuillermoObservations show that glaciers around the world are in retreat and losing mass. Internationally coordinated for over a century, glacier monitoring activities provide an unprecedented dataset of glacier observations from ground, air and space. Glacier studies generally select specific parts of these datasets to obtain optimal assessments of the mass-balance data relating to the impact that glaciers exercise on global sea-level fluctuations or on regional runoff. In this study we provide an overview and analysis of the main observational datasets compiled by the World Glacier Monitoring Service (WGMS). The dataset on glacier front variations (~42 000 since 1600) delivers clear evidence that centennial glacier retreat is a global phenomenon. Intermittent readvance periods at regional and decadal scale are normally restricted to a subsample of glaciers and have not come close to achieving the maximum positions of the Little Ice Age (or Holocene). Glaciological and geodetic observations (~5200 since 1850) show that the rates of early 21st-century mass loss are without precedent on a global scale, at least for the time period observed and probably also for recorded history, as indicated also in reconstructions from written and illustrated documents. This strong imbalance implies that glaciers in many regions will very likely suffer further ice loss, even if climate remains stable.Item Glacier mass changes of lake-terminating Grey and Tyndall glaciers at the southern patagonia icefield derived from geodetic observations and energy and mass balance modeling(Frontiers Media, 2018-06-19) Weidemann, Stephanie S.; Sauter, Tobías; Malz, Phillip; Jaña, Ricardo; Arigony-Neto, Jorge; Casassa, Gino; Scheneider, Christoph; Schuler, Thomas VikhamarIn this study we demonstrate how energy andmass fluxes vary in space and time for Grey and Tyndall glaciers at the Southern Patagonia Icefield (SPI). Despite the overall glacier retreat of most Patagonian glaciers, a recent increase in mass loss has been observed, but individual glaciers respond differently in terms of spatial and temporal changes. In this context, the detailed investigation of the effect of mass balance processes on recent glacier response to climate forcing still needs refinement. We therefore quantify surface energy-fluxes and climatic mass balance of the two neighboring glaciers, Grey and Tyndall. The COupled Snow and Ice energy and MAss balance model COSIMA is applied to assess recent surface energy and climatic mass balance variability with a high temporal and spatial resolution for a 16-year period between April 2000 and March 2016. The model is driven by downscaled 6-hourly atmospheric data derived from ERA-Interim reanalysis and MODIS/Terra Snow Cover and validated against ablation measurements made in single years. High resolution precipitation fields are determined by using an analytical orographic precipitation model. Frontal ablation is estimated as residual of climatic mass balance and geodetic mass balance derived from TanDEM-X/SRTM between 2000 and 2014. We simulate a positive glacier-wide mean annual climatic mass balance of +1.02 ± 0.52mw.e. a−1 for Grey Glacier and of +0.68 ± 0.54mw.e. a−1 for Tyndall Glacier between 2000 and 2014. Climatic mass balance results show a high year to year variability. Comparing climatic mass balance results with previous studies underlines the high uncertainty in climatic mass balance modeling with respect to accumulation on the SPI. Due to the lack of observations accumulation estimates differ from previous studies based on the methodological approaches. Mean annual ice loss by frontal ablation is estimated to be 2.07 ± 0.70mw.e. a−1 for Grey Glacier and 3.26 ± 0.82mw.e. a−1 for Tyndall Glacier between 2000 and 2014. Ice loss by surface ablation exceeds ice loss by frontal ablation for both glaciers. The overall mass balance of Grey and Tyndall glaciers are clearly negative with −1.05 ± 0.18mw.e. a−1 and −2.58 ± 0.28mw.e. a−1 respectively.Item Boletín Antártico Chileno(2005-09) Berguño Barnes, Jorge; Stehberg, Rubén; Pearson, Michael; Gatica, Carolina; Aguilar, Carolina; Torres, Daniel; Bown, Francisca; Rivera Ibáñez, Andrés; Casassa, Gino; Teitelboim, Claudio; Wendt, Jens; Ulloa, David; Thomas, Robert; Sonntag, John; Swift, Robert; Yungel, James; Frederick, Earl; Krabile, William; Abdalati, Waleed; Gogineni, Sivaprasad; Kanagaratnam, Pannirselvam; Sinclair, Rolf; Figueroa Ibarra, Miguel; Hervé, Francisco; Torres, Daniel; Bello, Maximiliano; Instituto Antártico Chileno; Ordóñez Kovacevic, Yasna; Julio Rocamora, Paulina; Torres, Daniel; Barticevic, ElíasItem Boletín Antártico Chileno(1999-11) Berguño Barnes, Jorge; Toledo de la Maza, Carlos; Pinochet de la Barra, Oscar; Casassa, Gino; Vallejos, Verónica; Hucke - Gaete, Rodrigo; Ramírez Aranda, Lucía; Eberhard, Patricio; Klock, Federico; Henríquez, Salomón; Instituto Antártico Chileno; Ordóñez Kovacevic, Yasna; Berguño Barnes, Jorge; Ríos Villalón, Juan; Ramírez Aranda, Lucía; Torres, DanielItem Boletín Antártico Chileno(2000-11) Casassa, Gino; Zúñiga, Gustavo; Torres, Daniel; Aguayo Lobo, Anelio; Eberhard, Patricio; Hervé, Francisco; Mesones Espinoza, Pedro; Anglés, Lucía; Instituto Antártico Chileno; Ordóñez Kovacevic, Yasna; Berguño Barnes, Jorge; Ríos Villalón, Juan; Torres, DanielItem Mass balance of the antarctic ice sheet at Patriot Hills(International Glaciological Society, 1998) Casassa, Gino; Brecher, Henry H.; Cárdenas, Carlos; Rivera, AndresGlaciological data col lected at Patriot Hills, Antarctica (80°18' S, 81 ~2' W), are used to assess the local mass balance of the ice sheet. The data were collected during two field campaigns conducted by the Instituto Antartico Chileno inJanuary and November 1995. Measurements included surveying of stakes, and ice thickness derived from discrete radar soundings with a ground-based high-frequency impulse system. Ablation occurred on the bare-ice field at the base of Patriot Hills, with a maximum value of 7 gem - 2 a- I. et accumulation was detected away from the mountains, over the firn-covered area of the glacier, with a maximum rate of 10 g cm 2 a '. Ice thickens rapidly away from the mountains, reaching a thickness of 383 m, the maximum range of the radar system, near the center of the blue-ice field. No significant difference in surface elevation of the ice was detected over the 305 d period, which indicates that the ice is in near-equilibrium at Patriot Hills.