Break‐up of the largest Arctic ice shelf and associated loss of an epishelf lake

Abstract. The Wilkins Ice Shelf is situated on the Antarctic Peninsula, a region where seven ice shelves disintegrated or retreated between 1995 and 2002. This study combines various remote sensing datasets from Wilkins Ice Shelf, with the aim of detecting its present and recent dynamics as well as recent changes. The survey includes structural mapping, ERS-1/2 SAR interferometry and analysis of ICESat GLAS ice surface elevation data. Ice front retreat rates from 1986 to 2008 showed several distinct break-up events, including one in February 2008, when 40% of a part of the ice shelf that connected two islands broke off. Surface elevations have been used to study tidal effects, crack formation and to estimate the ice thickness over the floating area. The derived interferometric velocities cover the south-eastern part of the ice shelf as well as major tributaries and reveal maximum inflow speeds of up to 330 m a−1. We show that drainage of melt ponds into crevasses were of no relevance for the break-up at Wilkins Ice Shelf. Buoyancy forces caused rift formation before the break-up in February 2008. Additionally, the evolution of failure zones of the order of tenths of kilometres in length in pre-conditioned locations at ice rises is shown. Investigation of the current (February 2009) situation shows that about 3100 km2 at the Northern Wilkins Ice Shelf are endangered, however, there is no visible signature that the remaining 8000 km2 are at risk.

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The role of an Arctic ice shelf in the climate of the MIS 6 glacial maximum (140 ka)

Quaternary Science Reviews ◽

10.1016/j.quascirev.2010.06.023 ◽

2010 ◽

Vol 29 (25-26) ◽

pp. 3590-3597 ◽

Cited By ~ 5

Author(s):

F. Colleoni ◽

G. Krinner ◽

M. Jakobsson

Keyword(s):

Glacial Maximum ◽

Ice Shelf ◽

Arctic Ice

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Arctic Ice Island and Ice Shelf Studies: Part II

ARCTIC ◽

10.14430/arctic3687 ◽

1960 ◽

Vol 13 (1) ◽

Cited By ~ 53

Author(s):

A.P. Crary

Keyword(s):

Ice Shelf ◽

Arctic Ice

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The Decay of an Annual Cover of Sea Ice

Journal of Glaciology ◽

10.3189/s0022143000022310 ◽

1972 ◽

Vol 11 (63) ◽

pp. 337-344 ◽

Cited By ~ 1

Author(s):

M. P. Langleben

Keyword(s):

Sea Ice ◽

Open Water ◽

Ice Cover ◽

Shortwave Radiation ◽

The Arctic ◽

Surrounding Water ◽

Complete Disintegration ◽

Break Up ◽

Arctic Ice ◽

Time Required

AbstractIn his now classic book L’dy Arktiki [Arctic ice], Zubov discussed the melting of sea ice during the Arctic summer by thermal interaction with the surrounding water and derived an expression which indicates that the proportion of open water increases exponentially with time until total ice-free conditions result. His equation predicts that the time required for complete decay of the ice cover after initial break-up is greater than one month and more likely as long as two months for representative values of incident shortwave radiation and initial ice thickness upon break-up. It is unlikely that above-freezing temperatures persist for this length of time.To explain the observed complete disintegration of the annual ice cover in many sheltered areas of the Arctic, a modified model of the thermal decay process has been introduced. This model takes into account the influence of radiation absorbed by the ice which was not included in the Zubov formulation. Considerable reduction in the time required for complete decay, generally by about a factor of 2 if an albedo of 0.4 is assumed for the ice surface, is obtained.

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Remote Sensing of Sea-Ice Growth and Melt-Pool Evolution, Milne Ice Shelf, Ellesmere Island, Canada

Annals of Glaciology ◽

10.1017/s0260305500000525 ◽

1987 ◽

Vol 9 ◽

pp. 145-150 ◽

Cited By ~ 2

Author(s):

Martin O. Jeffries ◽

William M. Sackinger ◽

Harold V. Serson

Keyword(s):

Sea Ice ◽

Drainage System ◽

Outer Part ◽

The Arctic ◽

Ice Shelf ◽

Ice Shelves ◽

Ice Growth ◽

Radar Images ◽

Melt Pool ◽

Arctic Ice

Periodically since 1950, air photographs and SLAR images have been taken of the Arctic ice shelves. The study of air photographs and SLAR images of the outer part of Milne Ice Shelf had three aims: (1) to map losses and ice re-growth at the shelf front, (2) to map the evolution of melt pools on shelf ice and multi-year land-fast sea ice, and (3) to assess the usefulness of air photographs and SLAR for these purposes. For mapping of ice calvings and subsequent sea-ice growth, both air photographs and radar images have been used sucessfully. However, air photographs are better than radar for mapping ice-surface features. The ridge-and-trough systems that characterize the surface of the ice shelf and old sea ice are clearly visible on each type of imagery but, because of their larger scale, air photographs proved to be most useful for a study of melt-pool evolution. The orientation of the melt pools is parallel to the prevailing winds which drive water along the troughs. The drainage system evolves by a process of elongation and coalesence.

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The Wilkins Ice Shelf, Antarctica: break-up along failure zones

Journal of Glaciology ◽

10.3189/002214308787780012 ◽

2008 ◽

Vol 54 (188) ◽

pp. 943-944 ◽

Cited By ~ 22

Author(s):

Angelika Humbert ◽

Matthias Braun

Keyword(s):

Ice Shelf ◽

Break Up

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Prokaryotic diversity of arctic ice shelf microbial mats

Environmental Microbiology ◽

10.1111/j.1462-2920.2007.01516.x ◽

2008 ◽

Vol 10 (4) ◽

pp. 950-966 ◽

Cited By ~ 50

Author(s):

Eric M. Bottos ◽

Warwick F. Vincent ◽

Charles W. Greer ◽

Lyle G. Whyte

Keyword(s):

Microbial Mats ◽

Ice Shelf ◽

Prokaryotic Diversity ◽

Arctic Ice

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The role of ocean circulation in the propagation of rifts on ice shelves.

10.5194/egusphere-egu2020-10919 ◽

2020 ◽

Author(s):

Mattia Poinelli ◽

Eric Larour ◽

Riccardo Riva

Keyword(s):

Ocean Circulation ◽

Regional Climate ◽

Ice Sheets ◽

Ice Sheet ◽

Ice Shelf ◽

Ice Shelves ◽

Rift Propagation ◽

Break Up ◽

The Stability

The break-up of large ice shelves and the associated loss of ice are thought to play a destabilizing role in the ice sheet dynamics.&#160;Although ice shelves are a substantial buttressing source in the stability of continental ice sheets, the propagation of large rifts eventually leads to the break-up of icebergs into the ocean.&#160;As consequence, this loss of ice would trigger further glacier acceleration and ice sheets retreat, destabilizing the ice cap.&#160;Retreat and collapse of ice sheets are also thought to be related to regional climate warming.&#160;Indeed, satellite observations suggest that a warming surrounding would induce the ice sheet to progressive thinning and weakening.The prolongation of un-grounded ice into the ocean is often interrupted by the propagation of fractures that eventually separates large icebergs from the ice shelf.&#160;These fractures are called rifts and range from dimensions of 10 to 100 km.&#160;A recent example of such phenomena is the massive break-up of the Larsen C in July, 2017 which followed the disintegration of Larsen A in 1995 and the partial break-up of Larsen B in 2002.&#160;The tabular iceberg formed by Larsen C was limited by the propagation of a large rift that began in summer 2016, although the ice shelf had already been thinning since 1992.Rift initiation and propagation are thought to be the result of glaciological and oceanographic sources that trigger ice to break.&#160;Nonetheless, exact mechanisms remain elusive.&#160;The on-going project focuses on ice-ocean interactions in ice shelves that accommodate rifts by using oceanographic models.&#160;The goal is to couple rift propagation and ocean circulation underneath ice cavities in order to infer how basal melting affects the development of rifts.&#160;The numerical framework is developed within the capabilities of the MITgcm.&#160;We aim to identify the sensitivity of propagation rate and opening rate of rifts to variations in the ocean circulation that have occurred during the separation of part of the ice shelf.On a larger scale, we are interested in the role of rifting in the stability of Antarctic shelves.&#160;Therefore, we work toward a better understanding of which processes are involved in the triggering of rift propagation.

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Calving and rifting on the McMurdo Ice Shelf, Antarctica

Annals of Glaciology ◽

10.1017/aog.2017.12 ◽

2017 ◽

Vol 58 (75pt1) ◽

pp. 78-87 ◽

Cited By ~ 10

Author(s):

Alison F. Banwell ◽

Ian C. Willis ◽

Grant J. Macdonald ◽

Becky Goodsell ◽

David P. Mayer ◽

...

Keyword(s):

Time Lapse ◽

High Energy ◽

Global Dimension ◽

Far Field ◽

Ice Shelf ◽

Long Period ◽

Short Period ◽

Seismic Records ◽

Fast Ice ◽

Break Up

ABSTRACTOn 2 March 2016, several small en échelon tabular icebergs calved from the seaward front of the McMurdo Ice Shelf, and a previously inactive rift widened and propagated by ~3 km, ~25% of its previous length, setting the stage for the future calving of a ~14 km2 iceberg. Within 24 h of these events, all remaining land-fast sea ice that had been stabilizing the ice shelf broke-up. The events were witnessed by time-lapse cameras at nearby Scott Base, and put into context using nearby seismic and automatic weather station data, satellite imagery and subsequent ground observation. Although the exact trigger of calving and rifting cannot be identified definitively, seismic records reveal superimposed sets of both long-period (>10 s) sea swell propagating into McMurdo Sound from storm sources beyond Antarctica, and high-energy, locally-sourced, short-period (<10 s) sea swell, in the 4 days before the fast ice break-up and associated ice-shelf calving and rifting. This suggests that sea swell should be studied further as a proximal cause of ice-shelf calving and rifting; if proven, it suggests that ice-shelf stability is tele-connected with far-field storm conditions at lower latitudes, adding a global dimension to the physics of ice-shelf break-up.

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