E-Thesis 126 views 19 downloads
Impact of Tides and Calving on Glacier Flow / JAMES COLINESE
Swansea University Author: JAMES COLINESE
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PDF | E-Thesis – open access
Copyright: The Author, James Colinese, 2023 Distributed under the terms of a Creative Commons Attribution 4.0 License (CC BY 4.0).
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Abstract
Globally, sea level rise poses an ever-increasing threat to coastal areas. Tidewater glaciers fed from the Greenland ice sheet directly (the second largest ice sheet on earth) interact with the sea and the ocean tides. Our understanding of the ocean interaction and tidewater glaciers is still develo...
| Published: |
Swansea University, Wales, UK
2024
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| Institution: | Swansea University |
| Degree level: | Master of Research |
| Degree name: | MRes |
| Supervisor: | Murray, T., Schlegel, R., Edwards, S., & Pearson, C. |
| URI: | https://cronfa.swan.ac.uk/Record/cronfa68061 |
| Abstract: |
Globally, sea level rise poses an ever-increasing threat to coastal areas. Tidewater glaciers fed from the Greenland ice sheet directly (the second largest ice sheet on earth) interact with the sea and the ocean tides. Our understanding of the ocean interaction and tidewater glaciers is still developing with regional and glacier-specific differences. During the 2013 summer, 20 GPS nodes were placed near the glacier front of Helheim Glacier for ~44 days, recording the position every 4-7 seconds. Iceberg calving resulted in many nodes being lost from the glacier front, with only 5 surviving the season. The GPS data was filtered using a Kalman filter to remove variance occurring from the harsh environment and inherent inaccuracies of GPS. This allowed the identification of long-term trends and tidal signals.Median horizontal glacier velocity ranged between 16 and 24m/d, with peaks reaching over 38m/d after some calving events. There is evidence of semi-diurnal modulation in both height and flow rate. Peak height varied slightly out of phase with the tide, with peak height occurring ~2 hours after high tide. Peak horizontal velocity occurred at low tide also with a~2-hour delay; this is attributed to the increased water depth at high tide buttressing Helheim Glacier and retarding flow; then, during low tide, there is less force allowing flowto increase. Semi-diurnal height modulation is found at the front centre of Helheim Glacier, showing that part of Helheim is semi-floating, because glacial earthquakes are also identified. During calving events, the glacier front saw flow speeds increase by 30% in some regions, and other portions experienced no changes, indicating that the flow regime of the glacier front is highly variable. This research shows the plethora of information available when using GPS data. Future research should explore the Kalman Filter and increased GPS usage focusing on long-term deployment across the glacier. |
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| Item Description: |
A selection of content is redacted or is partially redacted from this thesis to protect sensitive and personal information. |
| Keywords: |
Glaciology, GPS, Kalman Filter |
| College: |
Faculty of Science and Engineering |