Getting around Antarctica: new high-resolution mappings of the grounded and freely-floating boundaries of the Antarctic ice sheet created for the International Polar Year

Bindschadler, Robert; Choi, Hyeungu; Wichlacz, Amy; Bingham, Robert G.; Bohlander, J. A.; Brunt, Kelly M.; Corr, Hugh; Drews, Reinhard; Fricker, H. A.; Hall, Monica; Hindmarsh, Richard C. A.; Kohler, Jack; Padman, Laurie; Rack, Wolfgang; Rotschky, G.; Urbini, Stefano; Vornberger, Patricia; Young, Neal W.

doi:10.5194/tc-5-569-2011

Cited by 221 publications

(262 citation statements)

References 31 publications

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“…Our approach of delineating grounded ice with a steady grounding line over the entire 1992-2015 period does not take this into account. If the actual grounding-line position in the early 1990s was more seaward than inferred from data covering several years in the 2000s [Bindschadler et al, 2011], our approach would be biased toward later initiation times. However, the spreading rates would not be affected by this.…”

Section: Methodsmentioning

confidence: 99%

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Uneven onset and pace of ice‐dynamical imbalance in the Amundsen Sea Embayment, West Antarctica

Konrad

Gilbert

Cornford

et al. 2017

Geophysical Research Letters

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We combine measurements acquired by five satellite altimeter missions to obtain an uninterrupted record of ice sheet elevation change over the Amundsen Sea Embayment, West Antarctica, since 1992. Using these data, we examine the onset of surface lowering arising through ice‐dynamical imbalance, and the pace at which it has propagated inland, by tracking elevation changes along glacier flow lines. Surface lowering has spread slowest (<6 km/yr) along the Pope, Smith, and Kohler (PSK) Glaciers, due to their small extent. Pine Island Glacier (PIG) is characterized by a continuous inland spreading of surface lowering, notably fast at rates of 13 to 15 km/yr along tributaries draining the southeastern lobe, possibly due to basal conditions or tributary geometry. Surface lowering on Thwaites Glacier (THG) has been episodic and has spread inland fastest (10 to 12 km/yr) along its central flow lines. The current episodes of surface lowering started approximately 10 years before the first measurements on PSK, around 1990 on PIG, and around 2000 on THG. Ice‐dynamical imbalance across the sector has therefore been uneven during the satellite record.

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Section: Methodsmentioning

confidence: 99%

“…Locally weighted scatterplot smoothing in time [Cleveland, 1979] of degree 1 with a 2.5 year window was applied, and the data were smoothed spatially using a Gaussian filter with = 3.5 km. Finally, since we were primarily concerned with grounded ice, we discarded all data seaward of the grounding line [Bindschadler et al, 2011].…”

Section: Methodsmentioning

confidence: 99%

Uneven onset and pace of ice‐dynamical imbalance in the Amundsen Sea Embayment, West Antarctica

Konrad

Gilbert

Cornford

et al. 2017

Geophysical Research Letters

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“…Approximately 74 % of the Antarctic ice sheet is surrounded by floating ice shelves (Bindschadler et al, 2011a) providing the interface for interactions between ice and ocean. Marine ice sheets -characterized by a bed elevation below sea level and sloping down towards the interior -can be destabilized leading to a marine ice sheet instability (Mercer, 1978;Schoof, 2007;Tsai et al, 2015).…”

Section: Introductionmentioning

confidence: 99%

Detecting high spatial variability of ice shelf basal mass balance, Roi Baudouin Ice Shelf, Antarctica

et al. 2017

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Abstract. Ice shelves control the dynamic mass loss of ice sheets through buttressing and their integrity depends on the spatial variability of their basal mass balance (BMB), i.e. the difference between refreezing and melting. Here, we present an improved technique -based on satellite observations -to capture the small-scale variability in the BMB of ice shelves. As a case study, we apply the methodology to the Roi Baudouin Ice Shelf, Dronning Maud Land, East Antarctica, and derive its yearly averaged BMB at 10 m horizontal gridding. We use mass conservation in a Lagrangian framework based on high-resolution surface velocities, atmosphericmodel surface mass balance and hydrostatic ice-thickness fields (derived from TanDEM-X surface elevation). Spatial derivatives are implemented using the total-variation differentiation, which preserves abrupt changes in flow velocities and their spatial gradients. Such changes may reflect a dynamic response to localized basal melting and should be included in the mass budget. Our BMB field exhibits much spatial detail and ranges from −14.7 to 8.6 m a −1 ice equivalent. Highest melt rates are found close to the grounding line where the pressure melting point is high, and the ice shelf slope is steep. The BMB field agrees well with on-site measurements from phase-sensitive radar, although independent radar profiling indicates unresolved spatial variations in firn density. We show that an elliptical surface depression (10 m deep and with an extent of 0.7 km × 1.3 km) lowers by 0.5 to 1.4 m a −1 , which we tentatively attribute to a transient adaptation to hydrostatic equilibrium. We find evidence for elevated melting beneath ice shelf channels (with melting being concentrated on the channel's flanks). However, farther downstream from the grounding line, the majority of ice shelf channels advect passively (i.e. no melting nor refreezing) toward the ice shelf front. Although the absolute, satellite-based BMB values remain uncertain, we have high confidence in the spatial variability on sub-kilometre scales. This study highlights expected challenges for a full coupling between ice and ocean models.

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“…We warmly thank World Radiation Monitoring Center for providing the Baseline Surface Network Radiation dataset at Neumayer station and Gert König-Langlo for the CL-51 ceilometer data and information about the visual observations. We further thank the Norwegian Polar Institute for the use of the free Quantarctica package, as well as Bindschadler et al (2011) and Bamber et al (2009) for the datasets.…”

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confidence: 99%

Blowing snow detection from ground-based ceilometers: application to East Antarctica

et al. 2017

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Abstract. Blowing snow impacts Antarctic ice sheet surface mass balance by snow redistribution and sublimation. However, numerical models poorly represent blowing snow processes, while direct observations are limited in space and time. Satellite retrieval of blowing snow is hindered by clouds and only the strongest events are considered. Here, we develop a blowing snow detection (BSD) algorithm for ground-based remote-sensing ceilometers in polar regions and apply it to ceilometers at Neumayer III and Princess Elisabeth (PE) stations, East Antarctica. The algorithm is able to detect (heavy) blowing snow layers reaching 30 m height. Results show that 78 % of the detected events are in agreement with visual observations at Neumayer III station. The BSD algorithm detects heavy blowing snow 36 % of the time at Neumayer (2011Neumayer ( -2015 and 13 % at PE station (2010)(2011)(2012)(2013)(2014)(2015)(2016). Blowing snow occurrence peaks during the austral winter and shows around 5 % interannual variability. The BSD algorithm is capable of detecting blowing snow both lifted from the ground and occurring during precipitation, which is an added value since results indicate that 92 % of the blowing snow is during synoptic events, often combined with precipitation. Analysis of atmospheric meteorological variables shows that blowing snow occurrence strongly depends on fresh snow availability in addition to wind speed. This finding challenges the commonly used parametrizations, where the threshold for snow particles to be lifted is a function of wind speed only. Blowing snow occurs predominantly during storms and overcast conditions, shortly after precipitation events, and can reach up to 1300 m a.g.l. in the case of heavy mixed events (precipitation and blowing snow together). These results suggest that synoptic conditions play an important role in generating blowing snow events and that fresh snow availability should be considered in determining the blowing snow onset.

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Getting around Antarctica: new high-resolution mappings of the grounded and freely-floating boundaries of the Antarctic ice sheet created for the International Polar Year

Cited by 221 publications

References 31 publications

Uneven onset and pace of ice‐dynamical imbalance in the Amundsen Sea Embayment, West Antarctica

Uneven onset and pace of ice‐dynamical imbalance in the Amundsen Sea Embayment, West Antarctica

Detecting high spatial variability of ice shelf basal mass balance, Roi Baudouin Ice Shelf, Antarctica

Blowing snow detection from ground-based ceilometers: application to East Antarctica

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