Seasonal Velocities on Nordenskiöldbreen, Svalbard

• Main Author: Ehwald, Lena Elisa
• Format: Bachelor Thesis
• Language: English
• Published: Uppsala universitet, Institutionen för geovetenskaper 2016
• Subjects: Nordenskiöldbreen; Svalbard; velocity; glaciers; climate change; mass balance; dynamical behaviour of glaciers; Glaciär; Nordenski öldbreen; isflöde; massbalans; klimatuppvärmnin; Arctic; Main Island; Svalbard Archipelago; Climate change; glacier; Global warming; Spitsbergen
• Online Access: http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-296682

Global warming leads to increased precipitation in the Arctic, as warmer air can carry more moisture. The consequence is that many arctic glaciers get steeper slopes over time as increased melt at their lower part causes thinning and increased solid precipitation in their upper regions leads to thickening of the glacier. Ice flow of glaciers is strongly controlled by the surface slope, where steeper slopes leads to increased ice flow. An altered flow regime of the glaciers can lead to unpredicted contributions to sea-level changes as more glacier ice is delivered to lower regions and eventually to the sea through calving of melt- runoff. Long-term measurements of ice-flow velocities are therefore crucial to receive a better understanding of how glaciers respond to climate changes in a temporal and spatial scale. This study investigates ice flow velocities measured over a period of 10 years between 2006 and 2015 on Nordenskiöldbreen, Svalbard. The poly-thermal outlet glacier is centrally located on Spitsbergen; the main island of the Svalbard archipelago (74N°,10°E /81N°,35°E). Ice-flow velocities are measured continuously using stand-alone single-frequency GPS receivers attached to 8 metal stakes along the central flow line of Nordenskiöldbreen. The Institute for Marine and Atmospheric research in Utrecht, the Netherlands (IMAU) has developed such GPS units to measure ice-flow velocities at low costs and all year-round. Ice flow velocities at the central-flow line of Nordenskiöldbreen for the period 2006-2016 are estimated to be between 40 and 60 m a-1. Results show that maximum ice flow velocities can reach up to 80 m a-1 and occur mainly in the beginning of July. The highest annual averaged velocity of 53.88 m a-1 was measured during summer 2014. Averaged ice-flow velocities show an increasing trend of about 1.78 m a-1 during summer seasons. Results are further compared with mass balance observations and temperature records to analyze how glacier systems respond to climate changes. Klimatuppvärmningen bidrar ...