Glacial Hydrology

Background

During my PostDoc at Stockholm University my research focus has partly shifted to investigate the response of mountain glaciers and specifically mountain glacier hydrology to climate warming. Using the 3 km², polythermal Storglaciären, which is known for its world's longest continuous mass balance record (since 1946) (, as a test bed allows long-term (decadal) and short-term (seasonal, diurnal) assessment of the glacier's response to changes in climate forcing. Of particular interest to me are decadal, seasonal and diurnal responses and changes in the morphology and structure of the englacial and subglacial drainage system to the climate-dependent, variable influx of melt and rainwater.

Research activities:

• A re-assessment of the structure and morphology of the englacial and subglacial drainage system of Storglaciären using fluorescent dye-tracing experiments, melt modeling and subglacial hydraulic potential  calculations (Key-collaborators: Dr. Andrew Fountain, Dr. Peter Jansson, Andrew Williamson)
• Comparison of the 2012 state of the subglacial drainage system structure and morphology with assessments from the 1980's and 1990's to quantify climate warming impact. (Key-collaborators: Dr. Neil Arnold, Dr. Ian Willis)
• Test of synthetic DNA tracers to characterize the subglacial drainage system structure of Storglaciären (Key-collaborators: Dr. Todd Walter, Dr. Steve Lyon)

Key Findings

• Reduction of the seasonal glacier storage (i.e. snow cover) activates rapid flow pathways that provide direct links for the fast and increased transport of rainwater to the stream.
• Loss of seasonal snow cover together with the more frequent occurrence of high-magnitude summer rainfall events increase the frequency and magnitude of floods in Tarfala Valley.
• Storglaciären's subglacial drainage system structure is adjusted to a glacier-wide steady state subglacial water pressure of 70-80% of ice overburden pressure. This means that melting is inadequate to keep flow pathways at atmospheric pressure, but that ice deformation is insufficiently high to sustain overburden pressure.
• With thinner ice and higher subglacial water fluxes with climate change, the drainage system structure may become adjusted to lower water pressure.
• Storglaciären is underlain by a single, highly efficient system that drains the area between the higher moulins and the snout, and another homogenously braided, but still hydraulically efficient, system draining the area beneath the lower moulins and which forms a confluence upglacier of the terminus with the highly efficient system.

Related publications

• Dahlke HE, Lyon SW, Karlin T, Rosqvist G and P Jansson. 2013. Isotopic investigation of runoff generation in a glacierized catchment, northern Sweden. Hydrological Processes, doi: 10.1002/hyp.9668.