Structure-from-Motion Using Historical Aerial Images to Analyse Changes in Glacier Surface Elevation

Mölg, Nico; Bolch, Tobias

doi:10.3390/rs9101021

Cited by 73 publications

(67 citation statements)

References 34 publications

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“…-1.32 my −1 between 1925 and 1953 and − 0.42 my −1 between 1953 and 1994, suggesting an increase in the glacier tongue thinning rates. Our values for the glacier tongue are also in line with the findings of Mölg and Bolch [52] who reported an average elevation change of −67 ± 5.3 my −1 for Zmuttgletscher (Swiss Alps), albeit for a larger area and a longer period, between 1946 and 2005.…”

Section: Discussionsupporting

confidence: 92%

Variations of Lys Glacier (Monte Rosa Massif, Italy) from the Little Ice Age to the Present from Historical and Remote Sensing Datasets

Fugazza¹,

Senese²,

Azzoni³

et al. 2021

Glaciers and the Polar Environment

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Alpine glaciers respond to climate imbalance by adjusting their mass and length. In turn, these changes modify the glacial and periglacial environment, leading to increased supraglacial debris cover, the development of glacial lakes and glacier fragmentation. In this research, we investigated the evolution of Lys Glacier (Monte Rosa Group), by studying length, area and volume changes, and evolution of its supraglacial debris cover and proglacial lakes by means of historical sources and high-resolution aerial and satellite orthophotos. Lys Glacier retreated almost continuously, by nearly 2 km, from its maximum Little Ice Age position. More recently, the glacier lost 11.91% of its area between 1975 and 2014 and underwent fragmentation in 2009. Over the same period, glacier fragmentation and tongue stagnation affected the formation and rapid growth of a series of ice-contact lakes and led to a non-linear debris cover evolution. The glacier was also subjected to strong volume losses, with more than 135 m thinning on the ablation tongue from 1991 to 2014. Analysis of the meteorological records (1927-present) from the closest weather station reveals a considerable increase in average annual temperatures by more than 1°C from the mean of 1971-1989 to the mean of 1990-2017.Glaciers 2 by global warming [1]. The response of a glacier to climate imbalance occurs initially through mass loss; eventually, the glacier adjusts to mass changes by changing its geometry, including area and length [2]. These geometric changes are also often accompanied by a shift in the glacier geomorphology, including an increase in the glacier debris cover, which can then decouple the glacier response from the temperature signal, and the appearance of thermokarst features such as kettles and ice-contact lakes [3], with possible impacts on glacier hazards downstream [4]. In fact, debris-covered glaciers and the expansion of supraglacial debris cover on debris-free glaciers are increasingly prominent features of the world's glaciated catchments in mountain regions including Himalaya [5], Karakoram [6,7], Andes [8], Alps [9], Southern Alps of New Zealand [10], and Caucasus [11].Over the past century, Italian glaciers have been shrinking at high rates [12][13][14]. Among these, Lys Glacier, located in the Monte Rosa massif (Figure 1), can be considered paradigmatic of the changes affecting alpine glaciers. Its response to increasing temperature and reduced accumulation is in fact similar to that of most glaciers in the Alps and elsewhere [14-17]: terminus retreat, area reduction and decreasing ice thickness. In addition, Lys Glacier has also recently shown other climate-related changes, including detachment of the main debris-covered tongue from the rest of the glacier body and possible separation of the two branches of the glacier tongue (Figure 1a); variations in supraglacial debris cover (both surface and thickness) on the glacier tongue, thermokarst features (e.g. kettle ponds) and processes (Figure 1b); and calving processes at the terminus where...

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Section: Discussionsupporting

confidence: 92%

Variations of Lys Glacier (Monte Rosa Massif, Italy) from the Little Ice Age to the Present from Historical and Remote Sensing Datasets

Fugazza¹,

Senese²,

Azzoni³

et al. 2021

Glaciers and the Polar Environment

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“…Several studies have found that errors in individual DEMs, both in the horizontal and vertical domain, propagate when calculating their difference, leading to inaccurate estima-tions of thickness and volume change (Berthier et al, 2007;Nuth and Kaab, 2011). In the present study, different approaches were adopted for georeferencing all the DEMs used in the analysis of the volume change of the Forni Glacier tongue (2007,2014,2016).…”

Section: Dem Co-registration For Glacier Thickness Change Estimationmentioning

confidence: 99%

“…In summary, although TLS point clouds are regarded as the most accurate (Naumann et al, 2013), they suffer from inhomogeneous point density and cumbersome logistics, and their potential in glacial environments is limited, unless a maximum uncertainty of 5-10 cm can be tolerated. Laser scanners are also employed on aerial platforms, including UAVs, where they can reconstruct terrain morphology with only slightly higher uncertainty than the terrestrial counterparts with a much greater coverage (Rayburg et al, 2009), but the high operational cost has limited the diffusion of this technique.…”

Section: Additional Remarksmentioning

confidence: 99%

Combination of UAV and terrestrial photogrammetry to assess rapid glacier evolution and map glacier hazards

Fugazza

Scaioni

Corti

et al. 2018

Nat. Hazards Earth Syst. Sci.

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Abstract. Tourists and hikers visiting glaciers all year round face hazards such as sudden terminus collapses, typical of such a dynamically evolving environment. In this study, we analyzed the potential of different survey techniques to analyze hazards of the Forni Glacier, an important geosite located in Stelvio Park (Italian Alps). We carried out surveys in the 2016 ablation season and compared point clouds generated from an unmanned aerial vehicle (UAV) survey, closerange photogrammetry and terrestrial laser scanning (TLS). To investigate the evolution of glacier hazards and evaluate the glacier thinning rate, we also used UAV data collected in 2014 and a digital elevation model (DEM) created from an aerial photogrammetric survey of 2007. We found that the integration between terrestrial and UAV photogrammetry is ideal for mapping hazards related to the glacier collapse, while TLS is affected by occlusions and is logistically complex in glacial terrain. Photogrammetric techniques can therefore replace TLS for glacier studies and UAV-based DEMs hold potential for becoming a standard tool in the investigation of glacier thickness changes. Based on our data sets, an increase in the size of collapses was found over the study period, and the glacier thinning rates went from 4.55 ± 0.24 m a −1 between 2007 and 2014 to 5.20 ± 1.11 m a −1 between 2014 and 2016.

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“…The distance between the seven GCPs and the location of the same GCPs computed by the model [13] can be considered as an indicator of its internal coherence. In detail, Table 1 shows the two indicators MAE and RMSE.…”

Section: Resultsmentioning

confidence: 99%

“…Unlike proprietary software, however, open source gives the possibility to examine [9,10], modify and redistribute the algorithms, and is particularly suitable for research reproducibility and replicability [11] and closer to the general concept of open science [12]. For this work, we have adopted MicMac, an open source photogrammetric software that implements SfM and and MVS algorithms [13]. …”

Section: Introductionmentioning

confidence: 99%

High Resolution Historical Topography: Getting More from Archival Aerial Photographs

Seccaroni

Santangelo

Marchesini

et al. 2018

The 2nd International Electronic Conference on Remote Sensing

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High resolution elevation data is a fundamental information for multiple applications in geomorphology spanning from visual analyses to modeling. Nowadays, gathering of high-quality elevation data relies on multiple sensors and technologies which can be mounted on terrestrial, aerial and satellite platforms. In the last years, the Structure from Motion (SfM) algorithms have made possible the acquisition of high and very-high resolution elevation data from optical images acquired with high overlapping rates at virtually no cost. Such a feature made it possible to exploit remote sensing archival imagery to build historical topographic information with unprecedented detail. However, despite the increasing number of applications of SfM algorithms in the scientific literature, still little has been done in terms optimization and quality evaluation of the results. We have applied the SfM algorithm developed in the photogrammetric open source software MicMac to six black and white aerial photographs taken in 1954 at 1:33.000 in a mountainous and steep area in Central Italy. The aim of the experiment consists in a quantitative evaluation of the digital surface models obtained for different scanning settings.

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Structure-from-Motion Using Historical Aerial Images to Analyse Changes in Glacier Surface Elevation

Cited by 73 publications

References 34 publications

Variations of Lys Glacier (Monte Rosa Massif, Italy) from the Little Ice Age to the Present from Historical and Remote Sensing Datasets

Variations of Lys Glacier (Monte Rosa Massif, Italy) from the Little Ice Age to the Present from Historical and Remote Sensing Datasets

Combination of UAV and terrestrial photogrammetry to assess rapid glacier evolution and map glacier hazards

High Resolution Historical Topography: Getting More from Archival Aerial Photographs

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