DOI: 10.5194/tc-15-2235-2021
论文题名: The temperature change shortcut: Effects of mid-experiment temperature changes on the deformation of polycrystalline ice
作者: Craw L. ; Treverrow A. ; Fan S. ; Peternell M. ; Cook S. ; McCormack F. ; Roberts J.
刊名: Cryosphere
ISSN: 19940416
出版年: 2021
卷: 15, 期: 5 语种: 英语
英文关键词: cryosphere
; ice core
; ice cover
; temperature effect
; temperature gradient
英文摘要: It is vital to understand the mechanical properties of flowing ice to model the dynamics of ice sheets and ice shelves and to predict their behaviour in the future. We can increase our understanding of ice physical properties by performing deformation experiments on ice in laboratories and examining its mechanical and microstructural responses. However, natural conditions in ice sheets and ice shelves extend to low temperatures (10 C), and high octahedral strains (>0.08), and emulating these conditions in laboratory experiments can take an impractically long time. It is possible to accelerate an experiment by running it at a higher temperature in the early stages and then lowering the temperature to meet the target conditions once the tertiary creep stage is reached. This can reduce total experiment run-Time by >1000 h; however it is not known whether this could affect the final strain rate or microstructure of the ice and potentially introduce a bias into the data. We deformed polycrystalline ice samples in uniaxial compression at 2 C before lowering the temperature to either 7 or 10 C, and we compared the results to constant-Temperature experiments. Tertiary strain rates adjusted to the change in temperature very quickly (within 3% of the total experiment runtime), with no significant deviation from strain rates measured in constant-Temperature experiments. In experiments with a smaller temperature step (2 to 7 C) there is no observable difference in the final microstructure between changing-Temperature and constant-Temperature experiments which could introduce a bias into experimental results. For experiments with a larger temperature step (2 to 10 C), there are quantifiable differences in the microstructure. These differences are related to different recrystallisation mechanisms active at 10 C, which are not as active when the first stages of the experiment are performed at 2 C. For studies in which the main aim is obtaining tertiary strain rate data, we propose that a mid-experiment temperature change is a viable method for reducing the time taken to run low-stress and low-Temperature experiments in the laboratory. © Copyright: Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/164672
Appears in Collections: 气候变化与战略
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作者单位: Institute for Marine and Antarctic Studies, University of Tasmania, Hobart, TAS, Australia; Department of Geology, University of Otago, Dunedin, New Zealand; Department of Earth Sciences, University of Gothenburg, Gothenburg, Sweden; Australian Antarctic Program Partnership, Institute for Marine and Antarctic Studies, University of Tasmania, Hobart, TAS, Australia; School of Earth, Atmosphere and Environment, Monash University, Melbourne, VIC, Australia; Australian Antarctic Division, Hobart, TAS, Australia
Recommended Citation:
Craw L.,Treverrow A.,Fan S.,et al. The temperature change shortcut: Effects of mid-experiment temperature changes on the deformation of polycrystalline ice[J]. Cryosphere,2021-01-01,15(5)