Ocean tides modulation of flow at Helheim Glacier, East Greenland, observed using GPS
Observations at high spatial and temporal resolution could be key for improving our understanding of the physical processes that govern outlet-glacier flow variations. We collected simultaneous high-rate GPS observations at several locations distributed along and across Helheim Glacier, East Greenla...
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ftdtupubl:oai:pure.atira.dk:publications/3a6fd88c-3a8f-45ad-a751-d6f143af96f5 2023-05-15T15:09:43+02:00 Ocean tides modulation of flow at Helheim Glacier, East Greenland, observed using GPS de Juan, Julia Elosegui, P. Nettles, M. Davis, J. L. Larsen, Tine B. Ahlstrøm, Andreas P. Andersen, M. L. Ekstrom, G. Forsberg, René Hamilton, G. S. Khan, Shfaqat Abbas Schild, K. M. Stearns, L. A. Stenseng, Lars 2009 https://orbit.dtu.dk/en/publications/3a6fd88c-3a8f-45ad-a751-d6f143af96f5 eng eng info:eu-repo/semantics/restrictedAccess de Juan , J , Elosegui , P , Nettles , M , Davis , J L , Larsen , T B , Ahlstrøm , A P , Andersen , M L , Ekstrom , G , Forsberg , R , Hamilton , G S , Khan , S A , Schild , K M , Stearns , L A & Stenseng , L 2009 , ' Ocean tides modulation of flow at Helheim Glacier, East Greenland, observed using GPS ' , 2009 AGU Fall Meeting , San Fransisco, CA , United States , 14/12/2009 - 18/12/2009 . conferenceObject 2009 ftdtupubl 2022-08-14T07:47:33Z Observations at high spatial and temporal resolution could be key for improving our understanding of the physical processes that govern outlet-glacier flow variations. We collected simultaneous high-rate GPS observations at several locations distributed along and across Helheim Glacier, East Greenland, during the four Arctic summers of 2006-2009, along with other geophysical observations, to study glacial earthquakes and glacier dynamics. GPSderived position estimates of centimeter-level precision reveal the surface expression of glaciological signals, occurring from sub-hourly to daily time-scales and beyond. We find that the flow velocity of Helheim Glacier is modulated by ocean tides in a region including both sides of the grounding line. An admittance analysis of the tidal signal shows an exponential decrease in amplitude with distance from the calving front, along with increasing time delays in both the vertical and horizontal components. Moreover, the along-flow admittance amplitude and time delay estimates are highly time dependent, both with a periodicity of ~15 days, thus suggesting a response to a fortnightly tidal frequency. In addition, we observe transitory increases in the amplitude of the tidally-driven flow response coinciding with glacial earthquakes events, which are associated to large losses of mass at the calving front and step-like increases in flow speed. We will present an analysis of the tidal modulation signals observed at Helheim and discuss how those signals may place new constraints on models for glacier flow variations. Conference Object Arctic East Greenland glacier Greenland Technical University of Denmark: DTU Orbit Arctic Greenland |
institution |
Open Polar |
collection |
Technical University of Denmark: DTU Orbit |
op_collection_id |
ftdtupubl |
language |
English |
description |
Observations at high spatial and temporal resolution could be key for improving our understanding of the physical processes that govern outlet-glacier flow variations. We collected simultaneous high-rate GPS observations at several locations distributed along and across Helheim Glacier, East Greenland, during the four Arctic summers of 2006-2009, along with other geophysical observations, to study glacial earthquakes and glacier dynamics. GPSderived position estimates of centimeter-level precision reveal the surface expression of glaciological signals, occurring from sub-hourly to daily time-scales and beyond. We find that the flow velocity of Helheim Glacier is modulated by ocean tides in a region including both sides of the grounding line. An admittance analysis of the tidal signal shows an exponential decrease in amplitude with distance from the calving front, along with increasing time delays in both the vertical and horizontal components. Moreover, the along-flow admittance amplitude and time delay estimates are highly time dependent, both with a periodicity of ~15 days, thus suggesting a response to a fortnightly tidal frequency. In addition, we observe transitory increases in the amplitude of the tidally-driven flow response coinciding with glacial earthquakes events, which are associated to large losses of mass at the calving front and step-like increases in flow speed. We will present an analysis of the tidal modulation signals observed at Helheim and discuss how those signals may place new constraints on models for glacier flow variations. |
format |
Conference Object |
author |
de Juan, Julia Elosegui, P. Nettles, M. Davis, J. L. Larsen, Tine B. Ahlstrøm, Andreas P. Andersen, M. L. Ekstrom, G. Forsberg, René Hamilton, G. S. Khan, Shfaqat Abbas Schild, K. M. Stearns, L. A. Stenseng, Lars |
spellingShingle |
de Juan, Julia Elosegui, P. Nettles, M. Davis, J. L. Larsen, Tine B. Ahlstrøm, Andreas P. Andersen, M. L. Ekstrom, G. Forsberg, René Hamilton, G. S. Khan, Shfaqat Abbas Schild, K. M. Stearns, L. A. Stenseng, Lars Ocean tides modulation of flow at Helheim Glacier, East Greenland, observed using GPS |
author_facet |
de Juan, Julia Elosegui, P. Nettles, M. Davis, J. L. Larsen, Tine B. Ahlstrøm, Andreas P. Andersen, M. L. Ekstrom, G. Forsberg, René Hamilton, G. S. Khan, Shfaqat Abbas Schild, K. M. Stearns, L. A. Stenseng, Lars |
author_sort |
de Juan, Julia |
title |
Ocean tides modulation of flow at Helheim Glacier, East Greenland, observed using GPS |
title_short |
Ocean tides modulation of flow at Helheim Glacier, East Greenland, observed using GPS |
title_full |
Ocean tides modulation of flow at Helheim Glacier, East Greenland, observed using GPS |
title_fullStr |
Ocean tides modulation of flow at Helheim Glacier, East Greenland, observed using GPS |
title_full_unstemmed |
Ocean tides modulation of flow at Helheim Glacier, East Greenland, observed using GPS |
title_sort |
ocean tides modulation of flow at helheim glacier, east greenland, observed using gps |
publishDate |
2009 |
url |
https://orbit.dtu.dk/en/publications/3a6fd88c-3a8f-45ad-a751-d6f143af96f5 |
geographic |
Arctic Greenland |
geographic_facet |
Arctic Greenland |
genre |
Arctic East Greenland glacier Greenland |
genre_facet |
Arctic East Greenland glacier Greenland |
op_source |
de Juan , J , Elosegui , P , Nettles , M , Davis , J L , Larsen , T B , Ahlstrøm , A P , Andersen , M L , Ekstrom , G , Forsberg , R , Hamilton , G S , Khan , S A , Schild , K M , Stearns , L A & Stenseng , L 2009 , ' Ocean tides modulation of flow at Helheim Glacier, East Greenland, observed using GPS ' , 2009 AGU Fall Meeting , San Fransisco, CA , United States , 14/12/2009 - 18/12/2009 . |
op_rights |
info:eu-repo/semantics/restrictedAccess |
_version_ |
1766340847365783552 |