Experiments on the interaction of ice sheets with the polar oceans
Antarctica and Greenland have been losing mass at an increasing rate over recent decades. The reducing volume of ice in Antarctica and Greenland has been a significant contribution to global sea level rise and will continue to be so in the future. Much of the mass loss occurs at the edge of the ice...
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ftanucanberra:oai:openresearch-repository.anu.edu.au:1885/117055 2024-01-14T10:01:17+01:00 Experiments on the interaction of ice sheets with the polar oceans McConnochie, Craig http://hdl.handle.net/1885/117055 https://doi.org/10.25911/5d723d24c6000 https://openresearch-repository.anu.edu.au/bitstream/1885/117055/4/McConnochie_Thesis_2017.pdf.jpg en eng b43751350 http://hdl.handle.net/1885/117055 doi:10.25911/5d723d24c6000 https://openresearch-repository.anu.edu.au/bitstream/1885/117055/4/McConnochie_Thesis_2017.pdf.jpg Ice sheets ice-ocean interactions laboratory experiments turbulent plume Greenland Antarctica Thesis (PhD) ftanucanberra https://doi.org/10.25911/5d723d24c6000 2023-12-15T09:37:15Z Antarctica and Greenland have been losing mass at an increasing rate over recent decades. The reducing volume of ice in Antarctica and Greenland has been a significant contribution to global sea level rise and will continue to be so in the future. Much of the mass loss occurs at the edge of the ice sheets where glaciers flow into the ocean. Interactions between the ice and the ocean are important in controlling the ablation rate of the glaciers. As such, there has been much recent work examining the response of ice shelves to changing ocean conditions. The majority of this work has used numerical models that allow a range of ocean conditions to be simulated. Here, we investigate the major ice-ocean interactions through idealized laboratory experiments. Initially, the effect of fluid temperature on the ablation of a vertical ice wall is investigated. At the low temperatures and oceanic salinities that our experiments were conducted at, the temperature at the ice-fluid interface will be below 0 degrees Celsius and the interface salinity will be non-zero. Because of this, it is useful to consider a driving temperature defined as the difference between the fluid temperature and the freezing point at the fluid salinity. It is shown that the ablation rate increases like the driving temperature to the 4/3 power, while the interface temperature increases almost linearly with the driving temperature. Ablation of an ice wall releases cold fresh water that rises up the ice face as a turbulent plume. This turbulent plume enhances the transport of heat and salt to the ice-fluid interface and helps to maintain ablation of the ice. The properties of the plume are investigated in detail and a model is developed that describes them. The ocean around Antarctica and Greenland is generally stably stratified in salinity. The effect of stratification is investigated to examine the potential sensitivity of the ice sheets to changes in ambient fluid stratification. Regimes are found where small changes in the strength of stratification ... Doctoral or Postdoctoral Thesis Antarc* Antarctica Greenland Ice Shelves Australian National University: ANU Digital Collections Greenland |
institution |
Open Polar |
collection |
Australian National University: ANU Digital Collections |
op_collection_id |
ftanucanberra |
language |
English |
topic |
Ice sheets ice-ocean interactions laboratory experiments turbulent plume Greenland Antarctica |
spellingShingle |
Ice sheets ice-ocean interactions laboratory experiments turbulent plume Greenland Antarctica McConnochie, Craig Experiments on the interaction of ice sheets with the polar oceans |
topic_facet |
Ice sheets ice-ocean interactions laboratory experiments turbulent plume Greenland Antarctica |
description |
Antarctica and Greenland have been losing mass at an increasing rate over recent decades. The reducing volume of ice in Antarctica and Greenland has been a significant contribution to global sea level rise and will continue to be so in the future. Much of the mass loss occurs at the edge of the ice sheets where glaciers flow into the ocean. Interactions between the ice and the ocean are important in controlling the ablation rate of the glaciers. As such, there has been much recent work examining the response of ice shelves to changing ocean conditions. The majority of this work has used numerical models that allow a range of ocean conditions to be simulated. Here, we investigate the major ice-ocean interactions through idealized laboratory experiments. Initially, the effect of fluid temperature on the ablation of a vertical ice wall is investigated. At the low temperatures and oceanic salinities that our experiments were conducted at, the temperature at the ice-fluid interface will be below 0 degrees Celsius and the interface salinity will be non-zero. Because of this, it is useful to consider a driving temperature defined as the difference between the fluid temperature and the freezing point at the fluid salinity. It is shown that the ablation rate increases like the driving temperature to the 4/3 power, while the interface temperature increases almost linearly with the driving temperature. Ablation of an ice wall releases cold fresh water that rises up the ice face as a turbulent plume. This turbulent plume enhances the transport of heat and salt to the ice-fluid interface and helps to maintain ablation of the ice. The properties of the plume are investigated in detail and a model is developed that describes them. The ocean around Antarctica and Greenland is generally stably stratified in salinity. The effect of stratification is investigated to examine the potential sensitivity of the ice sheets to changes in ambient fluid stratification. Regimes are found where small changes in the strength of stratification ... |
format |
Doctoral or Postdoctoral Thesis |
author |
McConnochie, Craig |
author_facet |
McConnochie, Craig |
author_sort |
McConnochie, Craig |
title |
Experiments on the interaction of ice sheets with the polar oceans |
title_short |
Experiments on the interaction of ice sheets with the polar oceans |
title_full |
Experiments on the interaction of ice sheets with the polar oceans |
title_fullStr |
Experiments on the interaction of ice sheets with the polar oceans |
title_full_unstemmed |
Experiments on the interaction of ice sheets with the polar oceans |
title_sort |
experiments on the interaction of ice sheets with the polar oceans |
url |
http://hdl.handle.net/1885/117055 https://doi.org/10.25911/5d723d24c6000 https://openresearch-repository.anu.edu.au/bitstream/1885/117055/4/McConnochie_Thesis_2017.pdf.jpg |
geographic |
Greenland |
geographic_facet |
Greenland |
genre |
Antarc* Antarctica Greenland Ice Shelves |
genre_facet |
Antarc* Antarctica Greenland Ice Shelves |
op_relation |
b43751350 http://hdl.handle.net/1885/117055 doi:10.25911/5d723d24c6000 https://openresearch-repository.anu.edu.au/bitstream/1885/117055/4/McConnochie_Thesis_2017.pdf.jpg |
op_doi |
https://doi.org/10.25911/5d723d24c6000 |
_version_ |
1788067088390160384 |