Recent variations of a debris-covered glacier (Brenva glacier) in the Italian Alps monitored by comparison of maps and digital orthophotos

Debris-covered glaciers are widespread in the mountain chains of Asia. They are also particularly common in New Zealand , in the Andes and in Alaska. Despite their relatively common occurrence, debris-covered glaciers have not been well studied. A debris cover that partially or completely masks the glacier ablation zone significantly influences the surface energy flux, the ablation rate and the discharge of meltwater streams. A multi-temporal analysis based on photogrammetry methodologies was used to assess changes volume and ablation rates

Sea Tide Influence on Ice Flow of David Drygalski’s Ice Tongue Inferred from Geodetic GNSS Observations and SAR Offset Tracking Analysis

David Glacier and Drygalski Ice Tongue are massive glaciers in Victoria Land, Antarctica. The ice from the East Antarctic Ice Sheet is drained through the former, and then discharged into the western Ross Sea through the latter. David Drygalski is the largest outlet glacier in Northern Victoria Land, floating kilometers out to sea. The floating and grounded part of the David Glacier are the main focus of this article. During the XXI Italian Antarctic Expedition (2005-2006), within the framework of the National Antarctic Research Programme (PNRA), two GNSS stations were installed at different points: the first close to the grounding line of David Glacier, and the second approximately 40 km downstream of the first one. Simultaneous data logging was performed by both GNSS stations for 24 days. In the latest data processing, the kinematic PPP technique was adopted to evaluate the dominant diurnal components and the very small semi-diurnal variations in ice motion induced by the ocean tide and the mean ice flow rates of both GNSS stations. Comparison of the GNSS time series with predicted ocean tide calculated from harmonic coefficients of the nearest tide gauge stations, installed at Cape Roberts and Mario Zucchelli Station, highlight different local response of the glacier to ocean tide, with a minor amplitude of vertical motion at a point partially anchored at the bedrock close to the grounding line. During low tide, the velocity of the ice flow reaches its daily maximum, in accordance with the direction of seawater outflow from the fjord into the ocean, while the greatest daily tidal excursion generates an increase in the horizontal ice flow velocity. With the aim to extend the analysis in spatial terms, five COSMO-SkyMED Stripmap scenes were processed. The comparison of the co-registered offset tracking rates, obtained from SAR images, with the GNSS estimation shows good agreement

Estimation of apparent thermal inertia of roofing materials from aerial thermal imagery

The rapid expansion of urban areas and soil sealing is enhancing the Urban Heat Island (UHI) phenomenon, especially during heat waves. The different thermal inertia of the building materials compared to natural surfaces is one of the major driving factors of UHI. The present contribution aims to test a methodology for mapping the Apparent Thermal Inertia (ATI)—a proxy that can be derived from remote sensing data—of roofing surfaces at the scale of an entire city and with a high spatial resolution. Day and night aerial thermal images with the resolution of 0.5 m were acquired over two test areas in Bologna (Italy), together with satellite multispectral data. Statistics on the buildings in the test areas are computed considering different classes of roofing materials (e.g. bituminous sheath, clay tiles, metal sheet, gravel tiles). Observed median ATI values for each class range from 0.03 to 0.09 K-1 with interquartile ranges between 0.02 and 0.14 K-1, so the intra-class variability in some cases appears higher than the variability among different material classes, proving the importance of ATI mapping for UHI investigations

Integrated Methodologies for the 3D Survey and the Structural Monitoring of Industrial Archaeology: The Case of the Casalecchio di Reno Sluice, Italy

The paper presents an example of integrated surveying and monitoring activities for the control of an ancient structure, the Casalecchio di Reno sluice, located near Bologna, Italy. Several geomatic techniques were applied (classical topography, high-precision spirit levelling, terrestrial laser scanning, digital close-range photogrammetry, and thermal imagery). All these measurements were put together in a unique reference system and used in order to study the stability and the movements of the structure over the period of time observed. Moreover, the metrical investigations allowed the creation of a 3D model of the structure, and the comparison between two situations, before and after the serious damages suffered by the sluice during the winter season 2008-2009. Along with the detailed investigations performed on individual portions of the structure, an analysis of the whole sluice, carried out at a regional scale, was done via the use of aerial photogrammetry, using both recently acquired images and historical photogrammetric coverage. The measurements were carried out as part of a major consolidation and restoration activity, carried out by the "Consorzio della Chiusa di Casalecchio e del Canale di Reno"

Recent (1975-2003) changes in the Miage debris covere glacier tongue (Mont Blanc, Italy) from analysis of aerial photos and maps

The present study aims at identifying any changes in volume and thickness of the Miage Glacier tongue (Mont Blanc Massif, Italy) during the period 1975-2003. The Miage glacier developed the largest part of its debris cover over the last century, now found mostly between the glacier terminus (about 1850 m a.s.l.) and the upper ablation tongue (c. 2400 m a.s.l.) on a surface area of c. 4 km 2 The period examined (1975-2003) addresses climate conditions which were glacier-favourable (around the . 1980s), as well as glacier-unfavourable (since the early to mid-1990s), thus contributing to an understanding of the behaviour of debris covered glaciers under a changing climate. The analysis was based on the comparison between digital elevation models (DEMs), derived from historical records, specifically maps (1975; scale 1:10,000) and photogrammetric surveys (1991 and 2003, scale 1:15,000). The results show a general glacier volume loss (\u201316.640 x 10 6 m 3 ( from 1975 to 2003; nevertheless if we focus on the two time sub-windows (i.e.: 1975-1991 and 1991-2003) opposite trends are found: in the period 1975-1991 the volume variation of the Miage Glacier was about +19.25 710 6 m 3 , in the period 1991-2003, on the other hand, a volume decrease of about \u201336.2 710 6 m 3 occurred. Analysis shows that volume changes were strongly influenced by the supraglacial debris coverage which on Miage glacier tongue modulates the magnitude and rates of buried ice ablation