Ice aprons and hanging glaciers : new insights from optical and SAR remote sensing of the Mont-Blanc massif (western European Alps)

• Main Author: Kaushik, Suvrat
• Other Authors: Chambéry, Ravanel, Ludovic, Trouvé, Emmanuel, Yan, Yajing, Magnin, Florence
• Format: Thesis
• Language: English
• Published: 2023
• Subjects: Permafrost; Glacier suspendu; Télédétection; Mont Blanc Massif; Hanging Glacier; Remote Sensing; 551.312; Mont Blanc; Ice; permafrost
• Online Access: http://www.theses.fr/2023CHAMA003/document

Although numerous in the Alpine ranges, hanging glaciers and ice/snow aprons on the high mountain permafrost-affected rock faces are poorly known glacial systems. Ice aprons are small ice bodies of irregular outlines lying on steep slopes. They are significant elements of high mountain landscapes, a glacial heritage due to the old age of the ice, and an essential condition for mountaineering. However, research dedicated to ice aprons is rare, and only in the past few years have a few localized studies been initiated to understand their physical behaviour and dynamics. On the other hand, small hanging glaciers on steep slopes are also critical components as they are a potential source of danger through avalanches triggered by the collapse of seracs or even their fronts. Although relatively rare, ice avalanches may severely threaten human lives, settlements and infrastructure. Even with their perceived importance, the relatively poor attention towards these glacier/ice bodies is because of their small size and association with complex topographies where their access is challenging.Through a multidisciplinary approach (geographic, field observations and remote sensing), this doctoral work aims to understand the origin, distribution, and dynamics of these particular glacier systems in the context of global warming. For this, we relied on a variety of datasets consisting of aerial, terrestrial and satellite (optical and RaDAR) images, meteorological datasets and in-situ measurements. The study area for this PhD was the Mont Blanc massif, a 550 km2 Alpine mountain range famous for some of the highest peaks in the Alps, including the Mont Blanc summit (4808 m a.s.l.). At first, we focused our attention on ice aprons, ubiquitous in all the major mountain ranges worldwide, yet poorly defined perennial ice bodies. We built a regional inventory of ice aprons (n. 423) for the study region and, using this inventory redefined ice aprons based on their topographic characteristics. The inventory presented here is the first ...