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

Goel, Vikram; Brown, Jacqueline A.; Matsuoka, Kenichi

doi:10.5194/tc-11-2883-2017

Cited by 14 publications

(40 citation statements)

References 50 publications

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“…Further east in the Fimbul Ice Shelf, three ice rises have Raymond arches, with no double lineations. Radargrams from these three ice rises, Blåskimen Island (Goel and others, 2017), Kupol Moskovskij (#2, Fig 6a), and Kupol Ciolkovskogo (#6, Fig 6b), show Raymond arches with amplitudes >0.1 H and so we classify all three as case II. Although, arches in all three ice rises are tilted and show an offset from the ice divide with the largest offset visible in Kupol Moskovskij (~0.7 km).…”

Section: Past Stability Of Dml Ice Risesmentioning

confidence: 80%

“…The dome-shaped Blåskimen Island Ice Rise (#695) lies at the calving front west of Jutulstraumen Glacier, elevated ~350 m above the surrounding ice shelf and grounded on a nearly flat bed 100 m below sea level (Goel and others, 2017). Vega and others (2016) analyzed a 20-m-long firn core drilled at the summit, finding an SMB average of 0.70 m weq a −1 between 1996 and 2013.…”

Section: The Dml and Enderby Land Coastsmentioning

confidence: 99%

“…Ice rises in DML are thin (~300–500 m) and have large SMB (0.3–1 m a −1 ), so their bases should be well below the pressure-melting point (Pattyn, 2010; Liefferinge and Pattyn, 2013). For example, at Blåskimen Island, the basal temperature is −9.2°C according to a steady-state model with a geothermal flux of 60 mW m −2 (Goel and others, 2017). This geothermal flux value is within the expected range of 45–65 mW m −2 for the coastal DML region (An and others, 2015).…”

Section: Past Stability Of Dml Ice Risesmentioning

confidence: 99%

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Characteristics of ice rises and ice rumples in Dronning Maud Land and Enderby Land, Antarctica

et al. 2020

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Ice rises and rumples, locally grounded features adjacent to ice shelves, are relatively small yet play significant roles in Antarctic ice dynamics. Their roles generally depend upon their location within the ice shelf and the stage of the ice-sheet retreat or advance. Large, long-stable ice rises can be excellent sites for deep ice coring and paleoclimate study of the Antarctic coast and the Southern Ocean, while small ice rises tend to respond more promptly and can be used to reveal recent changes in regional mass balance. The coasts of Dronning Maud Land (DML) and Enderby Land in East Antarctica are abundant with these features. Here we review existing knowledge, presenting an up-to-date status of research in these regions with focus on ice rises and rumples. We use regional datasets (satellite imagery, surface mass balance and ice thickness) to analyze the extent and surface morphology of ice shelves and characteristic timescales of ice rises. We find that large parts of DML have been changing over the past several millennia. Based on our findings, we highlight ice rises suitable for drilling ice cores for paleoclimate studies as well as ice rises suitable for deciphering ice dynamics and evolution in the region.

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Section: Past Stability Of Dml Ice Risesmentioning

confidence: 80%

Section: The Dml and Enderby Land Coastsmentioning

confidence: 99%

Section: Past Stability Of Dml Ice Risesmentioning

confidence: 99%

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Characteristics of ice rises and ice rumples in Dronning Maud Land and Enderby Land, Antarctica

et al. 2020

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“…Conway et al, 1999;Martín et al, 2006Martín et al, , 2014, and ice-rise residence time (e.g. Drews et al, 2013Drews et al, , 2015Goel et al, 2017). Common to all these studies is the comparison of the observed isochrones derived from radar data, with the predicted age fields from models with varying input scenarios.…”

Section: Introductionmentioning

confidence: 99%

Kinematic response of ice-rise divides to changes in ocean and atmosphere forcing

et al. 2019

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Abstract. The majority of Antarctic ice shelves are bounded by grounded ice rises. These ice rises exhibit local flow fields that partially oppose the flow of the surrounding ice shelves. Formation of ice rises is accompanied by a characteristic upward-arching internal stratigraphy (“Raymond arches”), whose geometry can be analysed to infer information about past ice-sheet changes in areas where other archives such as rock outcrops are missing. Here we present an improved modelling framework to study ice-rise evolution using a satellite-velocity calibrated, isothermal, and isotropic 3-D full-Stokes model including grounding-line dynamics at the required mesh resolution (<500 m). This overcomes limitations of previous studies where ice-rise modelling has been restricted to 2-D and excluded the coupling between the ice shelf and ice rise. We apply the model to the Ekström Ice Shelf, Antarctica, containing two ice rises. Our simulations investigate the effect of surface mass balance and ocean perturbations onto ice-rise divide position and interpret possible resulting unique Raymond arch geometries. Our results show that changes in the surface mass balance result in immediate and sustained divide migration (>2.0 m yr−1) of up to 3.5 km. In contrast, instantaneous ice-shelf disintegration causes a short-lived and delayed (by 60–100 years) response of smaller magnitude (<0.75 m yr−1). The model tracks migration of a triple junction and synchronous ice-divide migration in both ice rises with similar magnitude but differing rates. The model is suitable for glacial/interglacial simulations on the catchment scale, providing the next step forward to unravel the ice-dynamic history stored in ice rises all around Antarctica.

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“…1). Goel and others (2017) found that this ice rise is currently thickening, and also that the present summit has been stable for at least the past ~600 years. We test several hypotheses to elucidate the onset of recent thickening and past changes in surface mass balance (SMB).…”

Section: Introductionmentioning

confidence: 91%

Ice-rise stratigraphy reveals changes in surface mass balance over the last millennia in Dronning Maud Land

2018

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We use ice flow modelling to simulate the englacial stratigraphy of Blåskimen Island, an ice rise in Dronning Maud Land and elucidate the evolution of this data-sparse region. We apply a thermo-mechanically coupled Elmer/Ice model to a profile along flowlines and through the ice-rise summit, where surface mass balance (SMB), flow velocity and ice stratigraphy were recently measured. We conclude that: (i) the ice rise is presently thickening at a rate of 0.5~0.6 m ice equivalent per year (mieq a−1), which is twice an earlier estimate using the field data and the input–output method; (ii) present thickening started 20–40 years in the past, before which the ice rise was in a steady state; (iii) SMB contrast between the upwind and downwind slopes was stronger than the present value by ~23% (or 0.15 mieq a−1) prior to ~1100 years ago. Since then, this contrast has been decreasing overall. We surmise that these SMB changes are likely a result of synoptic-scale atmospheric changes, rather than local atmospheric changes controlled by local ice topography. Our technique effectively assimilates geophysical data, avoiding the complexity of ice flow beneath the ice divide. Thus, it could be applied to other ice rises to elucidate the recent glacial retreat.

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

Cited by 14 publications

References 50 publications

Characteristics of ice rises and ice rumples in Dronning Maud Land and Enderby Land, Antarctica

Characteristics of ice rises and ice rumples in Dronning Maud Land and Enderby Land, Antarctica

Kinematic response of ice-rise divides to changes in ocean and atmosphere forcing

Ice-rise stratigraphy reveals changes in surface mass balance over the last millennia in Dronning Maud Land

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