Ocean forced variability of Totten Glacier mass loss

Roberts, Jason L.; Galton-Fenzi, B; Paolo, F. S.; Donnelly, Claire; Gwyther, David; Padman, Laurie; Young, D. A.; Warner, Roland; Greenbaum, J. S.; Fricker, H. A.; Payne, Antony J.; Cornford, Stephen; Brocq, A. M. Le; Ommen, T. D. van; Blankenship, D. D.; Siegert, Martín J.

doi:10.1144/sp461.6

Cited by 48 publications

(65 citation statements)

References 54 publications

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“…Here relatively warm MCDW reaches the Totten and Moscow University ice shelves to drive rapid basal melt (Rintoul et al, ; Silvano et al, ). As in the Amundsen and Bellingshausen seas, rapid basal melt of the Totten and Moscow University ice shelves is associated with mass loss and acceleration of the grounded portion of the Totten and Moscow University glaciers (Greenbaum et al, ; Li et al, ; Mohajerani et al, ; Roberts et al, ). These observations suggest that MCDW drives mass loss of this sector of the East Antarctic Ice Sheet (Silvano et al, ), which holds the equivalent of 5 m of global sea level rise (Mohajerani et al, ).…”

Section: Introductionmentioning

confidence: 99%

Seasonality of Warm Water Intrusions Onto the Continental Shelf Near the Totten Glacier

et al. 2019

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Warm Modified Circumpolar Deep Water (MCDW) from the Southern Ocean drives rapid basal melt of the Totten Ice Shelf on the Sabrina Coast (East Antarctica), affecting the mass balance of the grounded Totten Glacier. Recent observations show that MCDW intrudes onto the continental shelf through a depression at the shelf break. Here we investigate such intrusions by combining (1) new oceanographic and bathymetric observations collected for two consecutive years by profiling floats in the depression south of the shelf break, (2) oceanographic measurements collected by conductivity‐temperature‐depth‐instrumented seals on continental slope, and (3) an ocean model. The depression provides a pathway for persistent inflow of warm (0‐1°C) MCDW to the inner shelf. In austral autumn and early winter MCDW intrusions were up to 0.5°C warmer and were ~75 m thicker than in spring and summer. The seasonality of the flow on the continental slope explains the seasonality of the intrusions. The MCDW layer on the continental slope is warmer and thicker to the east of the depression than to the west. In autumn and early winter a strong, top‐to‐bottom westward current (Antarctic Slope Current) transports the warmer and thicker MCDW layer along the slope and is diverted poleward at the eastern entrance of the depression. A bottom‐intensified eastward current (Antarctic Slope Undercurrent) develops in other months, allowing cooler and thinner intrusions to enter the depression from the west. Our study illustrates how circulation on the Antarctic slope regulates the ocean heat delivery to the continental shelf and ultimately to the ice shelves.

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Section: Introductionmentioning

confidence: 99%

Seasonality of Warm Water Intrusions Onto the Continental Shelf Near the Totten Glacier

et al. 2019

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“…The surface elevation (Blankenship et al, 2015) and ice thickness (Blankenship et al, 2012) data are interpolated using TELVIS (Thickness Estimation by a Lagrangian Validated Interpolation Scheme) (Roberts et al, 2011), to produce a 10 geometry which is glaciologically self-consistent and has previously been used to infer basal melt rates on the glacier (Roberts et al, 2017). The bedrock elevation, which is used to distinguish zones of grounded/floating ice, is taken from gravity inversions (Greenbaum et al, 2015).…”

Section: Glaciological Datamentioning

confidence: 99%

“…The glacier flow rate accelerates downstream of the grounding area, meaning the ice will stretch and thin, causing the basal cracks to widen as they move downstream. The water in the ocean cavity underneath the Totten IS is also known to be warm enough to drive melt of the ice (Gwyther et al, 2014;Rintoul et al, 2016;Roberts et al, 2017). As basal crevasses 5 are exposed to sea water one might also expect that the cracks will become wider and deeper by melting.…”

Section: Fracture Advectionmentioning

confidence: 99%

“…The evolution of basal fractures predicted here by the KPZ equation neglects spatial variations in melt rate across the ice shelf (e. g. Gwyther et al, 2014;Roberts et al, 2017), as well as variations in melt rate which have been predicted to occur within 15 basal features (Jordan et al, 2014;Millgate et al, 2013). It also does not include the effects of internal ice deformation and strain thinning, which are particularly significant near the calving front where the ice shelf is unconfined and spreads laterally.…”

Section: Fracture Advectionmentioning

confidence: 99%

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Modelled fracture and calving on the Totten Ice Shelf

Cook¹,

Åström²,

Zwinger³

et al. 2018

Preprint

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Abstract. The Totten Ice Shelf (IS) has a large drainage basin, much of which is grounded below sea level, leaving the glacier vulnerable to retreat through the Marine Ice Shelf Instability mechanism. The ice shelf has also been shown to be sensitive to changes in calving rate, as a very small retreat of the calving front from its current position is predicted to cause a change in flow at the grounding line. Therefore understanding the processes behind calving on the Totten IS is key to predicting its future sea level rise contribution. Here we use the Helsinki Discrete Element Model (HiDEM) to show that calving on the Totten IS 15 is controlled not only by locally produced fractures at the calving front, but is also influenced by basal fractures which are likely produced at the grounding line. Our model results show that regrounding points may be key areas of basal crevasse production, and can produce basal crevasses in both an along and across flow orientation. As well as affecting calving, along flow basal crevasses at the grounding line may be a possible precursor to basal channels. We use two additional models to examine the evolution of basal fractures as they advect downstream, demonstrating that both strain and ocean melt have the 20 potential to deform narrow fractures into the broad basal features observed near the calving front. The wide range of factors which influence fracture patterns and calving on this glacier will be a challenge for predicting its future mass loss.

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“…Meanwhile, across the other side of the continent in East Antarctica, Roberts et al (2017) use airborne radar, satellite data and numerical modelling to explain how iceflow changes observed on Totten Glacier relate to ocean-driven melting in a manner similar to that proposed across vulnerable margins in the Amundsen Sea.…”

Section: Introduction To the Volumementioning

confidence: 99%

Exploration of subsurface Antarctica: uncovering past changes and modern processes

Siegert

Jamieson

White

2017

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The Antarctic continent, which contains enough ice to raise sea level globally by around 60 m, is the last major scientific frontier on our planet. We know far more about the surfaces of the Moon, Mars and around half of Pluto than we do about the underside of the Antarctic ice sheet. Geophysical exploration is the key route to measuring the ice sheet's internal structure and the land on which the ice rests. From such measurements, we are able to reveal how the ice sheet flows, and how it responds to atmospheric and ocean warming. By examining landscapes that have been moulded by former ice flow, we are able to identify how the ice sheet behaved in the past. Geophysics is therefore critical to understanding change in Antarctica

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Ocean forced variability of Totten Glacier mass loss

Cited by 48 publications

References 54 publications

Seasonality of Warm Water Intrusions Onto the Continental Shelf Near the Totten Glacier

Seasonality of Warm Water Intrusions Onto the Continental Shelf Near the Totten Glacier

Modelled fracture and calving on the Totten Ice Shelf

Exploration of subsurface Antarctica: uncovering past changes and modern processes

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