Antarctic ice rise formation, evolution, and stability

Favier, Lionel; Pattyn, Frank

doi:10.1002/2015gl064195

Cited by 42 publications

(45 citation statements)

References 41 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Embedded into an ice shelf, an ice rise creates a zone of compression upstream of the ice rise that buttresses the ice shelf (Borstad et al, 2013). However, downstream of the ice rise the tensile forces leave a weak region subject to crevasses and thinner ice shelves (Favier and Pattyn, 2015). Also, ice rises strongly influence regional surface mass balance (SMB) (Lenaerts et al, 2014) and can significantly alter the timing of deglaciation of the ice sheet (Favier and Pattyn, 2015;Favier et al, 2016).…”

Section: Introductionmentioning

confidence: 99%

“…However, downstream of the ice rise the tensile forces leave a weak region subject to crevasses and thinner ice shelves (Favier and Pattyn, 2015). Also, ice rises strongly influence regional surface mass balance (SMB) (Lenaerts et al, 2014) and can significantly alter the timing of deglaciation of the ice sheet (Favier and Pattyn, 2015;Favier et al, 2016). Hence, although relatively small in areal footprint, ice rises can have far-reaching effects on Antarctic ice-sheet dynamics.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Glaciological settings and recent mass balance of Blåskimen Island in Dronning Maud Land, Antarctica

2017

View full text Add to dashboard Cite

Abstract. The ice-shelf-fringed coast of Dronning Maud Land in East Antarctica contains numerous ice rises that influence the dynamics and mass balance of the region. However, only a few of these ice rises have been investigated in detail. Here, we present field measurements of Blåskimen Island, an isle-type ice rise adjacent to Fimbul Ice Shelf. This ice rise is largely dome shaped, with a pronounced ridge extending to the south-west from its summit (410 m a.s.l.). Its bed is mostly flat and about 100 m below the current sea level. Shallow radar-detected isochrones dated with a firn core reveal that the surface mass balance is higher on the south-eastern (upwind) slope than on the north-western (downwind) slope by ∼ 37 %, and this pattern has persisted for at least the past decade. Moreover, arches in radar stratigraphy suggest that the summit of the ice rise has been stable for ∼ 600 years. Ensemble estimates of the mass balance using the input-output method show that this ice rise has thickened by 0.12-0.37 m ice equivalent per year over the past decade.

show abstract

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Glaciological settings and recent mass balance of Blåskimen Island in Dronning Maud Land, Antarctica

2017

View full text Add to dashboard Cite

show abstract

“…Because ice rises decelerate ice flowing from the continent towards the ocean, they play an important role in defining the dynamics of the sheet-shelf system. Favier and Pattyn (2015), for example, showed that ice rises significantly delay grounding-line retreat during deglaciation and hence impact the timing of sea level changes. In order to better understand the deglaciation history and inevitably also ice-sheet dynamics in the future, there is high interest in collecting observational data that testify to ice-rise evolution (Matsuoka and others, 2015).…”

Section: Introductionmentioning

confidence: 99%

Temporally stable surface mass balance asymmetry across an ice rise derived from radar internal reflection horizons through inverse modeling

et al. 2016

Self Cite

View full text Add to dashboard Cite

ABSTRACT. Ice rises are locally grounded parts of Antarctic ice shelves that play an important role in regulating ice flow from the continent towards the ocean. Because they protrude out of the otherwise horizontal ice shelves, ice rises induce an orographic uplift of the atmospheric flow, resulting in an asymmetric distribution of the surface mass balance (SMB). Here, we combine younger and older internal reflection horizons (IRHs) from radar to quantify this distribution in time and space across Derwael Ice Rise (DIR), Dronning Maud Land, Antarctica. We employ two methods depending on the age of the IRHs, i.e. the shallow layer approximation for the younger IRHs near the surface and an optimization technique based on an ice flow model for the older IRHs. We identify an SMB ratio of 2.5 between the flanks and the ice divide with the SMB ranging between 300 and 750 kg m −2 a −1. The SMB maximum is located on the upwind side, ∼4 km offset to today's topographic divide. The large-scale asymmetry is consistently observed in time until 1966. The SMB from older IRHs is less-well constrained, but the asymmetry has likely persisted for >ka, indicating that DIR has been a stable features over long time spans.

show abstract

“…Because ice rises (Goldberg and others, 2009;Favier and others, 2014;Favier and Pattyn, 2015) and ice rumples (Favier and others, 2012) affect the dynamics of the grounding line and that of the upstream catchment area, it is important to better understand what role these features play in defining the buttressing strength of ice shelves.…”

Section: Introductionmentioning

confidence: 99%

The control of an uncharted pinning point on the flow of an Antarctic ice shelf

et al. 2016

Self Cite

View full text Add to dashboard Cite

ABSTRACT. Antarctic ice shelves are buttressed by numerous pinning points attaching to the otherwise freely-floating ice from below. Some of these kilometric-scale grounded features are unresolved in Antarctic-wide datasets of ice thickness and bathymetry, hampering ice flow models to fully capture dynamics at the grounding line and upstream. We investigate the role of an 8.7 km 2 pinning point at the front of the Roi Baudouin Ice Shelf, East Antarctica. Using ERS interferometry and ALOS-PALSAR speckle tracking, we derive, on a 125 m grid spacing, surface velocities deviating by −5.2 ± 4.5 m a −1 from 37 on-site global navigation satellite systems-derived velocities. We find no evidence for ice flow changes on decadal time scales and we show that ice on the pinning point virtually stagnates, deviating the ice stream and causing enhanced horizontal shearing upstream. Using the BISICLES ice-flow model, we invert for basal friction and ice rigidity with three input scenarios of ice velocity and geometry. We show that inversion results are the most sensitive to the presence/absence of the pinning point in the bathymetry; surface velocities at the pinning point are of secondary importance. Undersampling of pinning points results in erroneous ice-shelf properties in models initialised by control methods. This may impact prognostic modelling for ice-sheet evolution in the case of unpinning.

show abstract

Antarctic ice rise formation, evolution, and stability

Cited by 42 publications

References 41 publications

Glaciological settings and recent mass balance of Blåskimen Island in Dronning Maud Land, Antarctica

Glaciological settings and recent mass balance of Blåskimen Island in Dronning Maud Land, Antarctica

Temporally stable surface mass balance asymmetry across an ice rise derived from radar internal reflection horizons through inverse modeling

The control of an uncharted pinning point on the flow of an Antarctic ice shelf

Contact Info

Product

Resources

About