A high-resolution bedrock map for the Antarctic Peninsula

Assessing and projecting the dynamic response of glaciers on the Antarctic Peninsula to changed atmospheric and oceanic forcing requires high-resolution ice thickness data as an essential geometric constraint for ice flow models. Here, we derive a complete bedrock data set for the Antarctic Peninsula north of 70° S on a 100 m grid. We calculate distributed ice thickness based on surface topography and simple ice dynamic modelling. Our approach is constrained with all available thickness measurements from Operation IceBridge and gridded ice flow speeds for the entire study region. The new data set resolves the rugged subglacial topography in great detail, indicates deeply incised troughs, and shows that 34% of the ice volume is grounded below sea level. The Antarctic Peninsula has the potential to raise global sea level by 69 ± 5 mm. In comparison to Bedmap2, covering all Antarctica on a 1 km grid, a significantly higher mean ice thickness (+48%) is found

Deriving the response of glaciers from an ice-dynamic model

The Tenth Symposium on Polar Science/Ordinary sessions: [OM] Polar Meteorology and Glaciology, Wed. 4 Dec. / 2F Auditorium, National Institute of Polar Researc

La parola del colpevole. A German Life: il fuori campo della Storia, il controcampo delle immagini

The essay examines A German Life, the interview-documentary of the over a hundred-year-old secretary of Goebbels, Brunhilde Pomsel. Rather than being interested in entering the behind the scenes of the Nazi regime, the film focuses on the marginality of this figure, nonetheless exemplary of the responsibility of German people in the ninetieth century tragedy. Her long account resembles thus a confession, challenged by other documents — the archival materials, mainly Nazi propaganda films, but also educational films made by the Allies — that work as a sort of reverse shot of the witness’ story. The images seem to imply the off-screen of a long-denied truth, but the propaganda quality of such materials reinforces the ambiguity of the testimony, thus revealing its opacity. The difficult access to trauma, its fundamental elusiveness is articulated in-between the visual and the aural, in-between words and images. At the same time, the film makes evident the act of revealing and that of hiding in both the archival materials and in the testimony. The fragmentary nature of the film mirrors that of memory, of its incomplete truth, while the contrast between the visual and the aural, sound and images, is strengthened by the film’s formal choices: the documentary does not resort to the voice over and mostly uses close-ups or extreme close-ups, without leaving escape to the viewer. A German Life, therefore, situates itself in the in-between of the objectivity of a document and the manifest incompleteness of vision, thus reclaiming its testimonial position.Il saggio analizza A German Life, film intervista all’ultracentenaria Brunhilde Pomsel, segretaria di Goebbels. Più che alla possibilità di accedere al dietro le quinte di uno dei luoghi chiave del potere nazista, il film è interessato alla marginalità di questa figura, esemplare della responsabilità del popolo tedesco nella catastrofe del Novecento. Il suo lungo racconto appare allora come una confessione, messa alla prova da altre testimonianze documentali – i materiali d’archivio, per lo più filmati di propaganda nazista o film educativi degli Alleati – che funzionano come controcampo delle parole del testimone. Se l’immagine apre al fuori campo di una verità a lungo negata, la natura propagandistica dei materiali sembra rafforzare l’ambigua qualità della testimonianza e svelarne l’opacità. Tra visivo e sonoro, tra parola e immagine, si articola il difficile accesso al trauma, la sua inafferrabilità costitutiva e, insieme, emergono le operazioni di disvelamento e nascondimento messe in atto tanto nel racconto quanto nei filmati. Se la struttura a frammenti del testo sembra replicare la natura frammentaria della memoria e la sua verità lacunosa, il contrasto tra visivo e sonoro, tra parola e immagine, viene rafforzato nelle scelte formali: il film rinuncia alla voce fuori campo e si affida a riprese molto ravvicinate, a primi e primissimi piani che non lasciano vie di fuga allo sguardo. A German Life si colloca in questa tensione tra oggettività del documento e parzialità dichiarata della visione, rivendicando la propria posizione testimoniale

Pensare per immagini: il (foto)amatore come figura della modernità estetica

A partire dall’attività fotografica del noto architetto milanese, Piero Portaluppi (1888-1967), l’intervento analizza il contributo delle pratiche amatoriali nei processi di appropriazione, definizione e diffusione del nuovo «regime percettivo» della modernità tecnologica. Come sostiene Laurence Allard, il (foto/cine)amatore è una figura della modernità estetica: «attore» e non solo spettatore di una «visione», organizzatore di uno sguardo e, insieme, di una nuova esperienza di relazione con il mondo e con la memoria

Ri-animare l’inanimato: cadaveri, statue e corpi redenti, nelle immagini

The essay explores the relationship between dead bodies, statues and photographs, individuating in the images not only a means for petrifying bodies, embalm them in time— as argued by Roland Barthes, Regis Debray and Philippe Dubois — but also a form of re-animation of the inanimate. A sort of living relic, the image is the frozen testimony of a fleeting vitality, a paradoxical form of “visible hiding” in which life and death are intertwined. The essay demonstrates this process in some contemporary works, moving from one by Linda Fregni Nagler, The Hidden Mother (2013), a series of portraits of babies from the late XIXth century, made possible thanks to the presence of an adult hidden as good as possible in the background in order to keep them still. In these bodies of babies still alive, but in which lives their very same corpse, death is a phantom, but also a tangible fear behind the photographi

Ice volume distribution and implications on runoff projections in a glacierized catchment

A dense network of helicopter-based ground-penetrating radar (GPR) measurements was used to determine the ice-thickness distribution in the Mauvoisin region. The comprehensive set of ice-thickness measurements was combined with an ice-thickness estimation approach for an accurate determination of the bedrock. A total ice volume of 3.69 ± 0.31 km<sup>3</sup> and a maximum ice thickness of 290 m were found. The ice-thickness values were then employed as input for a combined glacio-hydrological model forced by most recent regional climate scenarios. This model provided glacier evolution and runoff projections for the period 2010–2100. Runoff projections of the measured initial ice volume distribution show an increase in annual runoff of 4% in the next two decades, followed by a persistent runoff decrease until 2100. Finally, we checked the influence of the ice-thickness distribution on runoff projections. Our analyses revealed that reliable estimates of the ice volume are essential for modelling future glacier and runoff evolution. Wrong estimations of the total ice volume might even lead to deviations of the predicted general runoff trend

La messa in scena della felicità: film di famiglia e pratiche di riscrittura della memoria nel cinema di Found Footage

L'intervento analizza il ruolo dei film di famiglia nella configurazione sociale della memoria e delle pratiche sperimentali di found footage nella ri-scrittura audiovisiva delle memorie

The bedrock topography of Gries- and Findelengletscher

Knowledge of the ice thickness distribution of glaciers is important for glaciological and hydrological applications. In this contribution, we present two updated bedrock topographies and ice thickness distributions for Gries- and Findelengletscher, Switzerland. The results are based on ground-penetrating radar (GPR) measurements collected in spring 2015 and already-existing data. The GPR data are analysed using ReflexW software and interpolated by using the ice thickness estimation method (ITEM). ITEM calculates the thickness distribution by using principles of ice flow dynamics and characteristics of the glacier surface. We show that using such a technique has a significance advantage compared to a direct interpolation of the measurements, especially for glacier areas that are sparsely covered by GPR data. The uncertainties deriving from both the interpretation of the GPR signal and the spatial interpolation through ITEM are quantified separately, showing that, in our case, GPR signal interpretation is a major source of uncertainty. The results show a total glacier volume of 0.28±0.06 and 1.00±0.34 km3 for Gries- and Findelengletscher, respectively, with corresponding average ice thicknesses of 56.8±12.7 and 56.3±19.6 m

The role of glacier retreat for Swiss hydropower production

High elevation or high latitude hydropower production (HP) strongly relies on water resources that are influenced by glacier melt and are thus highly sensitive to climate warming. Despite of the wide-spread glacier retreat since the development of HP infrastructure in the 20th century, little quantitative information is available about the role of glacier mass loss for HP. In this paper, we provide the first regional quantification for the share of Alpine hydropower production that directly relies on the waters released by glacier mass loss, i.e. on the depletion of long-term ice storage that cannot be replenished by precipitation in the coming decades. Based on the case of Switzerland (which produces over 50% of its electricity from hydropower), we show that since 1980, 3.0%–4.0% (1.0–1.4 TWh yr−1) of the country-scale hydropower production was directly provided by the net glacier mass loss and that this share is likely to reduce substantially by 2040–2060. For the period 2070–2090, a production reduction of about 1.0 TWh yr−1 is anticipated. The highlighted strong regional differences, both in terms of HP share from glacier mass loss and in terms of timing of production decline, emphasize the need for similar analyses in other Alpine or high latitude regions