气候变化领域集成服务门户(CCPortal): Exploring mechanisms responsible for tidal modulation in flow of the Filchner-Ronne Ice Shelf

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DOI	10.5194/tc-14-17-2020
	Exploring mechanisms responsible for tidal modulation in flow of the Filchner-Ronne Ice Shelf
	Rosier S.H.R.; Gudmundsson G.H.
发表日期	2020
ISSN	19940416
EISSN	14
起始页码	17
结束页码	37
卷号	14 期号:1
英文摘要	An extensive network of GPS sites on the Filchner-Ronne Ice Shelf and adjoining ice streams shows strong tidal modulation of horizontal ice flow at a range of frequencies. A particularly strong (horizontal) response is found at the fortnightly (Msf) frequency. Since this tidal constituent is absent in the (vertical) tidal forcing, this observation implies the action of some non-linear mechanism. Another striking aspect is the strong amplitude of the flow perturbation, causing a periodic reversal in the direction of ice shelf flow in some areas and a 10 %-20% change in speed at grounding lines. No model has yet been able to reproduce the quantitative aspects of the observed tidal modulation across the entire Filchner-Ronne Ice Shelf. The cause of the tidal ice flow response has, therefore, remained an enigma, indicating a serious limitation in our current understanding of the mechanics of large-scale ice flow. A further limitation of previous studies is that they have all focused on isolated regions and interactions between different areas have, therefore, not been fully accounted for. Here, we conduct the first largescale ice flow modelling study to explore these processes using a viscoelastic rheology and realistic geometry of the entire Filchner-Ronne Ice Shelf, where the best observations of tidal response are available. We evaluate all relevant mechanisms that have hitherto been put forward to explain how tides might affect ice shelf flow and compare our results with observational data. We conclude that, while some are able to generate the correct general qualitative aspects of the tidally induced perturbations in ice flow, most of these mechanisms must be ruled out as being the primary cause of the observed long-period response. We find that only tidally induced lateral migration of grounding lines can generate a sufficiently strong long-period Msf response on the ice shelf to match observations. Furthermore, we show that the observed horizontal short-period semidiurnal tidal motion, causing twicedaily flow reversals at the ice front, can be generated through a purely elastic response to basin-wide tidal perturbations in the ice shelf slope. This model also allows us to quantify the effect of tides on mean ice flow and we find that the Filchner-Ronne Ice Shelf flows, on average, ∼21% faster than it would in the absence of large ocean tides. © Author(s) 2020.
学科领域	flow modeling; GPS; ice flow; ice shelf; rheology; slope dynamics; tidal constituent; tidewater glacier; viscoelasticity; Antarctica; Filchner-Ronne Ice Shelf; West Antarctica
语种	英语
scopus关键词	flow modeling; GPS; ice flow; ice shelf; rheology; slope dynamics; tidal constituent; tidewater glacier; viscoelasticity; Antarctica; Filchner-Ronne Ice Shelf; West Antarctica
来源期刊	The Cryosphere
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/118786
作者单位	Department of Geography and Environmental Sciences, Northumbria University, Newcastle upon Tyne, NE1 8ST, United Kingdom
推荐引用方式 GB/T 7714	Rosier S.H.R.,Gudmundsson G.H.. Exploring mechanisms responsible for tidal modulation in flow of the Filchner-Ronne Ice Shelf[J],2020,14(1).
APA	Rosier S.H.R.,&Gudmundsson G.H..(2020).Exploring mechanisms responsible for tidal modulation in flow of the Filchner-Ronne Ice Shelf.The Cryosphere,14(1).
MLA	Rosier S.H.R.,et al."Exploring mechanisms responsible for tidal modulation in flow of the Filchner-Ronne Ice Shelf".The Cryosphere 14.1(2020).