Glacier dynamics and subsurface classification of Austfonna, Svalbard: : Inferences from observations and modelling

• Published in: Annals of Glaciology
• Main Author: Dunse, Thorben
• Other Authors: Jon Ove Hagen, Thomas Vikhamar Schuler
• Format: Doctoral or Postdoctoral Thesis
• Language: English
• Published: 2011
• Subjects: VDP::450; Arctic; Austfonna; Svalbard; Svalbard Archipelago; albedo; Annals of Glaciology; Climate change; glacier; Global warming; International Polar Year; IPY; Journal of Glaciology; The Cryosphere
• Online Access: http://hdl.handle.net/10852/12328; http://urn.nb.no/URN:NBN:no-29147

Ice loss from glaciers and ice caps in the Arctic constitute a major contribution to eustatic sea-level rise. Climate change is more pronounced in the Arctic than in other regions, because strong feedback mechanisms such as the albedo feedback lead to enhancement of the initial warming trend. Glaciers and ice caps serve as valuable indicators of past and present climate. However, extraction of climate signals from glaciers is not straightforward. The history, current state and future evolution of glaciers result from external factors, e.g. air temperature or precipitation, and intrinsic glacier dynamics, such as changes in thermal structure or subglacial drainage. Climatically-driven and dynamic processes may interact with each other and either moderate or amplify the glacier’s response to climate change. This thesis is a contribution to the project GLACIODYN: ’The dynamic response of Arctic glaciers to global warming’, under the framework of the International Polar Year (IPY) 2007–10. It addresses the dynamic behaviour and mass balance regime of Austfonna by combining geophysical techniques for glacier observation and numerical modelling. Austfonna is one of the largest ice caps in the Arctic and by far the largest land-ice mass on the highly glacierized Svalbard archipelago. Observed interior thickening and marginal thinning of Austfonna during the last decade is presumably related to slow glacier dynamics of several basins that are known to have surged in the past and are currently in the quiescent phase. The observed changes may also partly be imposed by changes in the surface mass balance (SMB). Austfonna’s total mass balance during the last decade was negative. Ice-mass loss was primarily attributed to calving from marine terminating outlets and retreat of the marine ice margin. The calving flux depends on the rate at which ice is transported towards the calving front. Previous estimates rely on ice-surface velocity maps that represent snapshots during mid-1990s winter months. The spatial and temporal ...