气候变化领域集成服务门户(CCPortal): Crystallographic analysis of temperate ice on Rhonegletscher, Swiss Alps

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DOI	10.5194/tc-15-677-2021
	Crystallographic analysis of temperate ice on Rhonegletscher, Swiss Alps
	Hellmann S.; Kerch J.; Weikusat I.; Bauder A.; Grab M.; Jouvet G.; Schwikowski M.; Maurer H.
发表日期	2021
ISSN	19940416
起始页码	677
结束页码	694
卷号	15 期号:2
英文摘要	Crystal orientation fabric (COF) analysis provides information about the c-axis orientation of ice grains and the associated anisotropy and microstructural information about deformation and recrystallisation processes within the glacier. This information can be used to introduce modules that fully describe the microstructural anisotropy or at least direction-dependent enhancement factors for glacier modelling. The COF was studied at an ice core that was obtained from the temperate Rhonegletscher, located in the central Swiss Alps. Seven samples, extracted at depths between 2 and 79 m, were analysed with an automatic fabric analyser. The COF analysis revealed conspicuous four-maxima patterns of the c-axis orientations at all depths. Additional data, such as microstructural images, produced during the ice sample preparation process, were considered to interpret these patterns. Furthermore, repeated high-precision global navigation satellite system (GNSS) surveying allowed the local glacier flow direction to be determined. The relative movements of the individual surveying points indicated longitudinal compressive stresses parallel to the glacier flow. Finally, numerical modelling of the ice flow permitted estimation of the local stress distribution. An integrated analysis of all the data sets provided indications and suggestions for the development of the four-maxima patterns. The centroid of the four-maxima patterns of the individual core samples and the coinciding maximum eigenvector approximately align with the compressive stress directions obtained from numerical modelling with an exception for the deepest sample. The clustering of the c axes in four maxima surrounding the predominant compressive stress direction is most likely the result of a fast migration recrystallisation. This interpretation is supported by air bubble analysis of large-area scanning macroscope (LASM) images. Our results indicate that COF studies, which have so far predominantly been performed on cold ice samples from the polar regions, can also provide valuable insights into the stress and strain rate distribution within temperate glaciers. © 2021 Institute of Electrical and Electronics Engineers Inc.. All rights reserved.
英文关键词	alpine environment; crystallography; glacier flow; GNSS; ice core; microstructure; polar region; Rhone Glacier [Valais]; Switzerland; Switzerland; Valais
语种	英语
来源期刊	Cryosphere
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/202328
作者单位	Laboratory of Hydraulics, Hydrology and Glaciology (VAW), ETH Zurich, Zurich, Switzerland; Institute of Geophysics, ETH Zurich, Zurich, Switzerland; Alfred-Wegener-Institut Helmholtz-Zentrum für Polar- und Meeresforschung, Bremerhaven, Germany; Department of Geosciences, Eberhard Karls University of Tübingen, Tübingen, Germany; Department of Geography, University of Zurich, Zurich, Switzerland; Autonomous Systems Laboratory, ETH Zurich, Zurich, Switzerland; Paul Scherrer Institute, Villingen, Switzerland; GZG Computational Geoscience, Georg August University of Göttingen, Göttingen, Germany
推荐引用方式 GB/T 7714	Hellmann S.,Kerch J.,Weikusat I.,et al. Crystallographic analysis of temperate ice on Rhonegletscher, Swiss Alps[J],2021,15(2).
APA	Hellmann S..,Kerch J..,Weikusat I..,Bauder A..,Grab M..,...&Maurer H..(2021).Crystallographic analysis of temperate ice on Rhonegletscher, Swiss Alps.Cryosphere,15(2).
MLA	Hellmann S.,et al."Crystallographic analysis of temperate ice on Rhonegletscher, Swiss Alps".Cryosphere 15.2(2021).