Temporal Consolidation Strategy for Ground-Based Image Displacement Time Series: Application to Glacier Monitoring

Marsy, Guilhem; Vernier, Flavien; Trouvé, Emmanuël; Bodin, Xavier; Castaings, William; Walpersdorf, Andréa; Malet, Emmanuel; Girard, Blaise

doi:10.1109/jstars.2021.3115231

Cited by 3 publications

(2 citation statements)

References 17 publications

(24 reference statements)

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“…Digital image correlation is a common technique used to measure surface displacements using proximal (Evans, 2000;Ahn and Box, 2010;Schwalbe and Maas, 2017) and remotely sensed imagery (Scambos et al, 1992;Heid and Kääb, 2012b;Marsy et al, 2021;Dematteis and Giordan, 2021). The processing chain performed in the present study uses the open-source Glacier Image Velocimetry (GIV) toolbox (Van Wyk De Vries and Wickert, 2021).…”

Section: Glaciers' Surface Velocity Mappingmentioning

confidence: 99%

Morphodynamics of the Mont Blanc glaciers and their recent evolution

Troilo,

Dematteis,

Zucca

et al. 2023

Preprint

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Abstract. The surface velocity of glaciers is a key parameter that provides fundamental information on glacier dynamics and their adaptation to changes in climate; moreover, ice velocity measurements are a very important parameter for modelling glacier physics and their evolution. While a few decades ago ice velocity would rely on point measurements performed in the field, the processing of high temporal and spatial resolution information from satellites nowadays provides new insights and a vast quantity of data, on a global scale, for the measurement of ice velocity. As of today, few studies have been performed in Alpine regions, and rarely has the focus been on ice velocity evolution. In the present study, we analyse the average monthly velocities on Alpine glaciers in the Mont Blanc massif. Seven years of Sentinel-2 optical satellite imagery have been processed to obtain ice velocity data. The main objectives of the study are: (i) to characterise the variability of the velocity fields of such glaciers, referring both to their temporal (seasonal and interannual) and spatial variations; (ii) to find relationships between the morphology of glaciers and their kinematics. We measured the monthly velocities of thirty glaciers varying from 18.0 m yr-1 to 436.3 m yr-1, highlighting a breakpoint in the trends in 2020. This led to the identification of 13 glaciers showing accelerations of more than 20.0 m yr-2 between 2020 and 2022 compared to previous years. We identified five clusters of morphodynamic characteristics, thus describing five different glacier type classes.

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Section: Glaciers' Surface Velocity Mappingmentioning

confidence: 99%

Morphodynamics of the Mont Blanc glaciers and their recent evolution

Troilo,

Dematteis,

Zucca

et al. 2023

Preprint

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“…This information is used to produce a weekly or daily ice/rock instabilities bulletin to provide information on the evolution of hazards in relation to weather conditions. In the Alps, several glaciers are monitored by time-lapse cameras and automatic analysis of velocities and deformations for natural hazard prediction and evaluation, such as the Weissmies glacier in Switzerland [121], Argentière glacier on the French side of the MBM [122], and Planpincieux glacier [37] or Grandes Jorasses (Whymper glacier) on the Italian side [123].…”

Section: Design Of the Hazard Monitoringmentioning

confidence: 99%

The Taconnaz Rockfall (Mont-Blanc Massif, European Alps) of November 2018: A Complex and At-Risk Rockwall-Glacier-Torrent Morphodynamic Continuum

Ravanel,

Duvillard,

Astrade

et al. 2023

Applied Sciences

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The glacial and torrential basin of Taconnaz (Mont-Blanc massif, France) dominates the Chamonix valley. It is one of the major paths for snow avalanches in the Alps, often triggered by serac falls from the Taconnaz glacier. On 24 November 2018, the basin’s multi-risk nature was further accentuated by a new type of hazard with a rockfall triggered at c. 2700 m a.s.l. It travelled down over a distance of 1.85 km and stopped 165 m away from the construction site of a micro-hydroelectric power station. We studied the triggering conditions at the permafrost lower limit, the effects of the supra-glacial path on the flow patterns, and the fate of the scar and the deposit on torrential activity. By comparing a pre-event Structure from Motion model with a post-event LiDAR model, we estimated the volume of the scar to be 42,900 m3 (±5%). A numerical model was employed to simulate the rapid runout. It revealed the complexity of the flow, attributed to the sequestration of a part of the deposit in crevasses, the incorporation of a significant volume of ice resulting in a transition from a dry granular flow to a mud-like flow, and the presence of numerous deposit zones. Subsequent monitoring of the area after the event allowed for the documentation of the scar’s evolution, including a landslide, as well as the progressive degradation and evacuation of the deposit by the torrent without producing debris flow. The study of the triggering factors indicated glacial retreat as the probable main cause, assisted by the melting of ice lenses left by the permafrost disappearance. Finally, we present replicable methods for managing risks at the site following the event. This event improves the understanding of cascading processes that increasingly impact Alpine areas in the context of climate change.

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