Flow dynamics of the NE Greenland Ice Stream with hydrological insights from englacial exploration of Larsbreen, Svalbard
Open Access
- Author:
- Riverman, Kiya Lihn
- Graduate Program:
- Geosciences
- Degree:
- Doctor of Philosophy
- Document Type:
- Dissertation
- Date of Defense:
- February 15, 2017
- Committee Members:
- Sridhar Anandakrishnan, Dissertation Advisor/Co-Advisor
Richard Alley, Committee Chair/Co-Chair
Byron Parizek, Committee Member
Sridhar Anandakrishnan, Committee Member
Christopher Duffey, Outside Member - Keywords:
- glaciology
ice stream
geophysics
greenland
englacial hydrology
shear margin - Abstract:
- Glaciers and ice sheets are large reservoirs of freshwater. In order to project how these icy reservoirs will respond to future climate, predictive models must incorporate all relevant ice flow processes and dynamics. Here, I present observations of glaciers in Greenland and Svalbard that advance our understanding of the role of meltwater in rapid ice flow. Chapters 1-4 concern the North East Greenland Ice Stream (NEGIS), a large flow feature of the Greenland Ice Sheet that drains a catchment spanning ~11% of the ice sheet area. I investigate the controls on ice stream location using geophyscial and remote sensing techniques. I find water flow at the base of the ice is, in part, controlled by enhanced firn densification and surface elevation changes in areas of high stress. The basal conditions across the ice stream are very heterogeneous, with variable water content and till thickness (Chapters 2, 3). Under both shear margins, I find shear-marginal moraines, as well as mega-scale glacial lineations within the central trunk of the ice stream (Chapter 4). Chapters 5 and 6 concern the hydrology of cold glacier on Svalbard. I use glaciospeleology (ice caving) to map the englacial and subglacial channels on Larsbreen, Spitsbergen across 3 years. Waterfalls within the glacier migrate rapidly and dominate change within the englacial system each year. I suggest that formation and migration of the final waterfall to the bed of the glacier is a potentially large source of erosion.