Glacier Front Dynamics of Antarctica - Analysing Changes in Glacier and Ice Shelf Front Position based on SAR Time Series

• Main Author: Baumhoer, Celia Amélie
• Format: Doctoral or Postdoctoral Thesis
• Language: English
• Published: 2021
• Subjects: ddc:919; Antarctic; The Antarctic; Antarctic Peninsula; West Antarctica; Antarc*; Antarctica; Antarktis*; Ice Sheet; Ice Shelf; Ice Shelves
• Online Access: https://opus.bibliothek.uni-wuerzburg.de/frontdoor/index/index/docId/24581; https://nbn-resolving.org/urn:nbn:de:bvb:20-opus-245814; https://doi.org/10.25972/OPUS-24581; https://opus.bibliothek.uni-wuerzburg.de/files/24581/Baumhoer_Celia_Dissertation_Antarctica.pdf

The Antarctic Ice Sheet stores ~91% of the global ice volume which is equivalent to a sea-level rise of 58.3 meters. Recent disintegration events of ice shelves and retreating glaciers along the Antarctic Peninsula and West Antarctica indicate the current vulnerable state of the Antarctic Ice Sheet. Glacier tongues and ice shelves create a safety band around Antarctica with buttressing effects on ice discharge. Current decreases in glacier and ice shelf extent reduce the effective buttressing forces and increase ice discharge of grounded ice. The consequence is a higher contribution to sea-level rise from the Antarctic Ice Sheet. So far, it is unresolved which proportion of Antarctic glacier retreat can be attributed to climate change and which part to the natural cycle of growth and decay in the lifetime of a glacier. The quantitative assessment of the magnitude, spatial extent, distribution, and dynamics of circum-Antarctic glacier and ice shelf retreat is of utmost importance to monitor Antarctica’s weakening safety band. In remote areas like Antarctica, earth observation provides optimal properties for large-scale mapping and monitoring of glaciers and ice shelves. Nowadays, the variety of available satellite sensors, technical advancements regarding spatial resolution and revisit times, as well as open satellite data archives create an ideal basis for monitoring calving front change. A systematic review conducted within this thesis revealed major gaps in the availability of glacier and ice shelf front position measurements despite the improved satellite data availability. The previously limited availability of satellite imagery and the time-consuming manual delineation of calving fronts did neither allow a circum-Antarctic assessment of glacier retreat nor the assessment of intra-annual changes in glacier front position. To advance the understanding of Antarctic glacier front change, this thesis presents a novel automated approach for calving front extraction and explores drivers of glacier retreat. A ...