Rigorosum David Farias – 02.09.2021

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Project: „Detailed quantification and interpretation of glacier elevation and mass changes in the Southern Andes and South Georgia“

David Farias (FAU)

Betreuer: Prof. Dr. Matthias Braun

Wann: Donnerstag, 02. September 2021
Wo: Aufgrund der noch immer geltenden Ausführungsbestimmungen zur Promotionsprüfung muss die Prüfung leider unter Ausschluss der Öffentlichkeit stattfinden.

Glaciers are very sensitive to climate change and have shown to be in a strong imbalance with the present climate. The glacier model projections from the IPCC report (2019) showed a glacier decline in all the scenarios, losing a considerable part of their masses to the end of the present 21st century. However, the ability of models’ projections to reproduce efficiently and precisely does not only rely on refine models, but also on the availability of the satellite and ground-based quality data to calibrate and validate those models. Overall, the glacier changes have several implications for physical, biological, and human systems, affecting the water availability for downstream communities and contributing to the sea-level rise.

Close and long-range remote sensing techniques offer the potential for repeated measurements of the glacier variables (such as glacier mass balance). In the last decades, the number of sensors and methods has increased considerably, allowing time series analysis as well as new and more precise measurements of glacier changes. The aim of this thesis is to investigate and provide a detailed quantification of glacier elevation and mass changes of the Southern Andes with a strong focus on the Central Andes of Chile and South Georgia.

In this study, the glacier changes were estimated using a variety of remote sensing techniques (i.e. InSAR, LiDAR, Maps, satellite images) and the first Andes continent-wide glacier elevation and mass balance is presented. Overall, glaciers are retreating and thinning across the Andes. The largest contribution comes from Patagonian glaciers (83%).  A detailed times series of glacier area, mass, and runoff changes were performed on individual glaciers and regional level in the central Andes of Chile. In this latter region, glaciers also showed important thinning rates. However, unlike in Patagonia, they represent a critical natural resource as they provide freshwater for the densely populated metropolitan region of Chile. This research closes with the first island-wide glacier elevation and mass changes study for South Georgia glaciers, one of the largest sub-Antarctic Islands.

The results of this thesis shed light on the recent changes and current glacier status in the Southern Andes and South Georgia, providing valuable and key long-term spatial-temporal datasets to further calibrate and validate hydrological and glaciological projections; as well as for the implementation of water management plans that can be useful for stakeholders to develop adaptation or mitigation strategies (i.e. central Andes of Chile).This study also shows that multi-sensors sources from historical cartography to modern techniques as LiDAR and InSAR data, combined with precise post-processing provide reliable datasets to quantify glacier changes over extended periods of time, where in-situ measurements are poor or do not exist.