The influence of a model subglacial lake on ice dynamics and internal layering
As ice flows over a subglacial lake, the drop in bed resistance leads to an increase in ice velocities and a draw down of isochrones and cold ice. The ice surface flattens as it adjusts to the lack of resisting forces at the base. The rapid transition in velocity induces changes in ice viscosity and...
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ftdoajarticles:oai:doaj.org/article:03a61ba0877142bd89942342f9adb5a9 2023-05-15T14:01:12+02:00 The influence of a model subglacial lake on ice dynamics and internal layering E. Gudlaugsson A. Humbert T. Kleiner J. Kohler K. Andreassen 2016-04-01T00:00:00Z https://doi.org/10.5194/tc-10-751-2016 https://doaj.org/article/03a61ba0877142bd89942342f9adb5a9 EN eng Copernicus Publications http://www.the-cryosphere.net/10/751/2016/tc-10-751-2016.pdf https://doaj.org/toc/1994-0416 https://doaj.org/toc/1994-0424 1994-0416 1994-0424 doi:10.5194/tc-10-751-2016 https://doaj.org/article/03a61ba0877142bd89942342f9adb5a9 The Cryosphere, Vol 10, Iss 2, Pp 751-760 (2016) Environmental sciences GE1-350 Geology QE1-996.5 article 2016 ftdoajarticles https://doi.org/10.5194/tc-10-751-2016 2022-12-31T01:37:29Z As ice flows over a subglacial lake, the drop in bed resistance leads to an increase in ice velocities and a draw down of isochrones and cold ice. The ice surface flattens as it adjusts to the lack of resisting forces at the base. The rapid transition in velocity induces changes in ice viscosity and releases deformation energy that can raise the temperature locally. Recent studies of Antarctic subglacial lakes indicate that many lakes experience very fast and possibly episodic drainage, during which the lake size is rapidly reduced as water flows out. Questions that arise are what effect this would have on internal layers within the ice and whether such past drainage events could be inferred from isochrone structures downstream. Here, we study the effect of a subglacial lake on ice dynamics as well as the influence that such short timescale drainage would have on the internal layers of the ice. To this end, we use a full Stokes, polythermal ice flow model. An enthalpy-gradient method is used to account for the evolution of temperature and water content within the ice. We find that a rapid transition between slow-moving ice outside the lake, and full sliding over the lake, can release considerable amounts of deformational energy, with the potential to form a temperate layer at depth in the transition zone. In addition, we provide an explanation for a characteristic surface feature commonly seen at the edges of subglacial lakes, a hummocky surface depression in the transition zone between little to full sliding. We also conclude that rapid changes in the horizontal extent of subglacial lakes and slippery patches, compared to the average ice column velocity, can create a traveling wave at depth within the isochrone structure that transfers downstream with the advection of ice, thus indicating the possibility of detecting past drainage events with ice penetrating radar. Article in Journal/Newspaper Antarc* Antarctic The Cryosphere Directory of Open Access Journals: DOAJ Articles Antarctic The Cryosphere 10 2 751 760 |
institution |
Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
Environmental sciences GE1-350 Geology QE1-996.5 |
spellingShingle |
Environmental sciences GE1-350 Geology QE1-996.5 E. Gudlaugsson A. Humbert T. Kleiner J. Kohler K. Andreassen The influence of a model subglacial lake on ice dynamics and internal layering |
topic_facet |
Environmental sciences GE1-350 Geology QE1-996.5 |
description |
As ice flows over a subglacial lake, the drop in bed resistance leads to an increase in ice velocities and a draw down of isochrones and cold ice. The ice surface flattens as it adjusts to the lack of resisting forces at the base. The rapid transition in velocity induces changes in ice viscosity and releases deformation energy that can raise the temperature locally. Recent studies of Antarctic subglacial lakes indicate that many lakes experience very fast and possibly episodic drainage, during which the lake size is rapidly reduced as water flows out. Questions that arise are what effect this would have on internal layers within the ice and whether such past drainage events could be inferred from isochrone structures downstream. Here, we study the effect of a subglacial lake on ice dynamics as well as the influence that such short timescale drainage would have on the internal layers of the ice. To this end, we use a full Stokes, polythermal ice flow model. An enthalpy-gradient method is used to account for the evolution of temperature and water content within the ice. We find that a rapid transition between slow-moving ice outside the lake, and full sliding over the lake, can release considerable amounts of deformational energy, with the potential to form a temperate layer at depth in the transition zone. In addition, we provide an explanation for a characteristic surface feature commonly seen at the edges of subglacial lakes, a hummocky surface depression in the transition zone between little to full sliding. We also conclude that rapid changes in the horizontal extent of subglacial lakes and slippery patches, compared to the average ice column velocity, can create a traveling wave at depth within the isochrone structure that transfers downstream with the advection of ice, thus indicating the possibility of detecting past drainage events with ice penetrating radar. |
format |
Article in Journal/Newspaper |
author |
E. Gudlaugsson A. Humbert T. Kleiner J. Kohler K. Andreassen |
author_facet |
E. Gudlaugsson A. Humbert T. Kleiner J. Kohler K. Andreassen |
author_sort |
E. Gudlaugsson |
title |
The influence of a model subglacial lake on ice dynamics and internal layering |
title_short |
The influence of a model subglacial lake on ice dynamics and internal layering |
title_full |
The influence of a model subglacial lake on ice dynamics and internal layering |
title_fullStr |
The influence of a model subglacial lake on ice dynamics and internal layering |
title_full_unstemmed |
The influence of a model subglacial lake on ice dynamics and internal layering |
title_sort |
influence of a model subglacial lake on ice dynamics and internal layering |
publisher |
Copernicus Publications |
publishDate |
2016 |
url |
https://doi.org/10.5194/tc-10-751-2016 https://doaj.org/article/03a61ba0877142bd89942342f9adb5a9 |
geographic |
Antarctic |
geographic_facet |
Antarctic |
genre |
Antarc* Antarctic The Cryosphere |
genre_facet |
Antarc* Antarctic The Cryosphere |
op_source |
The Cryosphere, Vol 10, Iss 2, Pp 751-760 (2016) |
op_relation |
http://www.the-cryosphere.net/10/751/2016/tc-10-751-2016.pdf https://doaj.org/toc/1994-0416 https://doaj.org/toc/1994-0424 1994-0416 1994-0424 doi:10.5194/tc-10-751-2016 https://doaj.org/article/03a61ba0877142bd89942342f9adb5a9 |
op_doi |
https://doi.org/10.5194/tc-10-751-2016 |
container_title |
The Cryosphere |
container_volume |
10 |
container_issue |
2 |
container_start_page |
751 |
op_container_end_page |
760 |
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1766270799211134976 |