Subsurface fluxes of mass and energy at the accumulation zone of Lomonosovfonna ice cap, Svalbard

• Main Author: Marchenko, Sergey
• Format: Doctoral or Postdoctoral Thesis
• Language: English
• Published: Uppsala universitet, Luft-, vatten- och landskapslära 2018
• Subjects: glacier; ice sheet; sea level; runoff; ice; firn; snow; stratigraphy; density; core; radar; thermistor; temperature; preferential water flow; thermal conductivity; water content; Physical Geography; Naturgeografi; Lomonosovfonna; Svalbard; Ice cap; Ice Sheet
• Online Access: http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-334178

Glaciers cover ca 10% of the Earth's land and are found in the high altitudes and latitudes. They are important components of environmental systems due to the multiple feedbacks linking them with the atmosphere, hydrosphere and periglacial landscapes. The cold sloping surfaces of glaciers change the patterns of atmospheric circulation at different scales and at the same time glaciers are largely controlled by climate. They are commonly used as climatic archives for reconstruction of the past environmental changes based on evidences from the areas affected by glaciation at the moment and in the past. Glaciers are the largest fresh-water reservoirs on our planet and runoff thereof significantly affects the global sea level and life in glaciated catchments. However, melt- and rain-induced runoff from glaciers greatly depends on the subsurface conditions which thus need to be taken into account, particularly in a changing climate. This thesis focuses on the processes of subsurface mass and energy exchange in the accumulation zones of glaciers, which are largely driven by the climate at the surface. Results are largely based on empirical data from Lomonosovfonna ice cap, Svalbard, collected during field campaigns in 2012-2017. Observations of subsurface density and stratigraphy using shallow cores, video records from boreholes and radar surveys returned detailed descriptions of the snow and firn layering. The subsurface temperature data collected using multiple thermistor strings provided insights into several subsurface processes. The temperature values measured during three summer seasons were used to constrain the suggested parameterization of deep preferential water flow through snow and firn. The part of data recorded during the cold seasons was employed for an inverse modelling exercise resulting in optimized values of effective thermal conductivity of the subsurface profile. These results are then used to compute the subsurface water content by comparing the simulated and measured rates of freezing front ...