Flow speed and calving rate of Kongsbreen glacier, Svalbard, using SPOT images

Lefauconnier, Bernard; Hagen, Jon Ove; Rudant, Jean Paul

doi:10.3402/polar.v13i1.6681

Cited by 69 publications

(74 citation statements)

References 3 publications

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“…The spatial velocity pattern and the characteristics of summer speed-up appear to be controlled by the distinct topography with the lower part of the glacier flowing over an escarpment and being channelled into a deep and narrow fjord. Likewise, Basin-3 has accelerated by about a factor of four compared to the 1990s and also showed an acceleration Lefauconnier et al, 1994) and recent summer maxima of 900 m a −1 (2.5 m d −1 ) measured at the calving front (Rolstad et al, 2009).…”

Section: Discussionmentioning

confidence: 93%

Seasonal speed-up of two outlet glaciers of Austfonna, Svalbard, inferred from continuous GPS measurements

et al. 2012

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Abstract.A large part of the ice discharge from ice caps and ice sheets occurs through spatially limited flow units that may operate in a mode of steady flow or cyclic surge behaviour. Changes in the dynamics of distinct flow units play a key role in the mass balance of Austfonna, the largest ice cap on Svalbard. The recent net mass loss of Austfonna was dominated by calving from marine terminating outlet glaciers. Previous ice-surface velocity maps of the ice cap were derived by satellite radar interferometry (InSAR) and rely on data acquired in the mid-1990s with limited information concerning the temporal variability. Here, we present continuous Global Positioning System (GPS) observations along the central flowlines of two fast flowing outlet glaciers over [2008][2009][2010]. The data show prominent summer speedups with ice-surface velocities as high as 240 % of the presummer mean. Acceleration follows the onset of the summer melt period, indicating enhanced basal motion due to input of surface meltwater into the subglacial drainage system. In 2008, multiple velocity peaks coincide with successive melt periods. In 2009, the major melt was of higher amplitude than in 2008. Flow velocities appear unaffected by subsequent melt periods, suggesting a transition towards a hydraulically more efficient drainage system. The observed annual mean velocities of Duvebreen and Basin-3 exceed those from the mid-1990s by factors two and four, respectively, implying increased ice discharge at the calving front. Measured summer velocities up to 2 m d −1 for Basin-3 are close to those of Kronebreen, often referred to as the fastest glacier on Svalbard.

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Section: Discussionmentioning

confidence: 93%

Seasonal speed-up of two outlet glaciers of Austfonna, Svalbard, inferred from continuous GPS measurements

et al. 2012

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“…We used all data as supplied, with the exception of Kongsbreen Glacier, where the reported ice thickness, inferred using the values from Pelto & Warren (1991), exceeded ice thicknesses reported elsewhere (Dowdeswell & Drewry 1989;Lefauconnier et al 1994) and resulted in an ice cliff towering more than 200 m above the water line. Owing to this discrepancy and the fact that we could not track down the original data, we removed these data points from the analysis.…”

Section: Comparison Of Theoretical Strength Envelopes With Observatiomentioning

confidence: 99%

Upper and lower limits on the stability of calving glaciers from the yield strength envelope of ice

2011

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Observations indicate that substantial changes in the dynamics of marine-terminating ice sheets and glaciers are tightly coupled to calving-induced changes in the terminus position. However, the calving process itself remains poorly understood and is not well parametrized in current numerical ice sheet models. In this study, we address this uncertainty by deriving plausible upper and lower limits for the maximum stable ice thickness at the calving face of marine-terminating glaciers, using two complementary models. The first model assumes that a combination of tensile and shear failure can render the ice cliff near the terminus unstable and/or enable pre-existing crevasses to intersect. A direct consequence of this model is that thick glaciers must terminate in deep water to stabilize the calving front, yielding a predicted maximum ice cliff height that increases with increasing water depth, consistent with observations culled from glaciers in West Greenland, Antarctica, Svalbard and Alaska. The second model considers an analogous lower limit derived by assuming that the ice is already fractured and fractures are lubricated by pore pressure. In this model, a floating ice tongue can only form when the ice entering the terminus region is relatively intact with few pre-existing, deeply penetrating crevasses.

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“…This coincided with intensive outXow coming from Kongsbreen glacier, where concentrations of suspended mineral solids reached 400 mg/l (Zajaczkowski 2008). Kongsbreen is described as the most active Spitsbergen glacier (Lefauconnier et al 1994). The highest deposition of mineral sediments occurs in the summer, when samples were collected.…”

Section: Comparison Of Meiofauna Between Hornsund and Kongsfjordenmentioning

confidence: 99%

Meiofaunal distribution in Hornsund fjord, Spitsbergen

Grzelak

Kotwicki

2011

Polar Biol

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The meiofaunal community structure at 32 stations in Hornsund fjord (77°N) was investigated, and results were compared with data from another Spitsbergen fjord, Kongsfjorden (79°N). Steep environmental gradients of sedimentation, organic matter content, and salinity from the inner to the outer basin of the fjord are present due to intensive glacial discharges of meltwater and ice. As the natural environmental disturbances were described for macrofauna benthic communities before, we aimed to check whether the same pattern occurs among meiofauna. A total of 12 higher meiofaunal taxa were recorded, with nematodes predominating at all stations. Non-parametric multivariate analyses demonstrated clear diVerences in meiofaunal abundance and composition between stations in the glacial bay and in the outer part of the fjord. Meiofaunal abundance increased with increasing distance from the source of disturbance, which in our study is tidal glaciers. Therefore, the current study demonstrates that the spatial structure of meiofauna is aVected by the natural environmental disturbance, and analysis of meiofaunal assemblages can be used to assess the eVect of such disturbances.

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Flow speed and calving rate of Kongsbreen glacier, Svalbard, using SPOT images

Cited by 69 publications

References 3 publications

Seasonal speed-up of two outlet glaciers of Austfonna, Svalbard, inferred from continuous GPS measurements

Seasonal speed-up of two outlet glaciers of Austfonna, Svalbard, inferred from continuous GPS measurements

Upper and lower limits on the stability of calving glaciers from the yield strength envelope of ice

Meiofaunal distribution in Hornsund fjord, Spitsbergen

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