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  • 1
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    Depth-averaged pure ice attenuation rates (two-way) from PISM model ensemble for Antarctica - link to NetCDF file (2018)
    PANGAEA
    Details
    Publication Date: 2023-03-16
    Keywords: Antarctica; AWI_Glac; Glaciology @ AWI
    Type: Dataset
    Format: application/x-netcdf, 12.8 MBytes
    Location Call Number Limitation Availability
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  • 2
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    Ice thickness for Recovery Glacier, Antarctica (2018)
    PANGAEA
    Details
    Publication Date: 2023-03-16
    Keywords: Antarctica; AWI_Glac; DATE/TIME; Glaciology @ AWI; Ice thickness, glacier; LATITUDE; LONGITUDE
    Type: Dataset
    Format: text/tab-separated-values, 104080 data points
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  • 3
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    Ice thickness from radio-echo sounding (RES) and radar attenuation from numerical modelling for Recovery Glacier, Antarctica (2018)
    PANGAEA
    In:  Supplement to: Humbert, Angelika; Steinhage, Daniel; Helm, Veit; Beyer, Sebastian; Kleiner, Thomas (2018): Missing Evidence of Widespread Subglacial Lakes at Recovery Glacier, Antarctica. Journal of Geophysical Research-Earth Surface, 123(11), 2802-2826, https://doi.org/10.1029/2017JF004591
    Details
    Publication Date: 2023-03-16
    Description: Recovery Glacier reaches far into the East Antarctic Ice Sheet. Recent projections point out that its dynamic behaviour has a considerable impact on future Antarctic ice loss (Golledge et al. 2017). Subglacial lakes are thought to play a major role in the initiation of the rapid ice flow (Bell et al. 2007). Satellite altimetry observations have even suggested several actively filling and draining subglacial lakes beneath the main trunk (Smith et al. 2009). We present new data of the geometry of this glacier and investigate its basal properties employing radio-echo sounding. Using ice-sheet modelling, we were able to constrain estimates of radar absorption in the ice, but uncertainties remain large. The magnitude of the basal reflection coefficient is thus still poorly known. However, its spatial variability, in conjunction with additional indicators, can be used to infer the presence of subglacial water. We find no clear evidence of water at most of the previously proposed lake sites. Especially locations where altimetry detected active lakes, do not exhibit lake characteristics in RES. We argue that lakes far upstream the main trunk are not triggering enhanced ice flow, which is also supported by modeled subglacial hydrology.
    Keywords: Antarctica; AWI_Glac; Glaciology @ AWI
    Type: Dataset
    Format: application/zip, 2 datasets
    Location Call Number Limitation Availability
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  • 4
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    Modelling calving front dynamics using a level-set method: application to Jakobshavn Isbræ, West Greenland, links model results in MATLAB format (2016)
    PANGAEA
    In:  Supplement to: Bondzio, Johannes H; Seroussi, Hélène; Morlighem, Mathieu; Kleiner, Thomas; Rückamp, Martin; Humbert, Angelika; Larour, Eric Y (2016): Modelling calving front dynamics using a level-set method: application to Jakobshavn Isbræ, West Greenland. The Cryosphere, 10(2), 497-510, https://doi.org/10.5194/tc-10-497-2016
    Details
    Publication Date: 2023-01-13
    Description: Calving is a major mechanism of ice discharge of the Antarctic and Greenland ice sheets, and a change in calving front position affects the entire stress regime of marine terminating glaciers. The representation of calving front dynamics in a 2-D or 3-D ice sheet model remains non-trivial. Here, we present the theoretical and technical framework for a level-set method, an implicit boundary tracking scheme, which we implement into the Ice Sheet System Model (ISSM). This scheme allows us to study the dynamic response of a drainage basin to user-defined calving rates. We apply the method to Jakobshavn Isbræ, a major marine terminating outlet glacier of the West Greenland Ice Sheet. The model robustly reproduces the high sensitivity of the glacier to calving, and we find that enhanced calving triggers significant acceleration of the ice stream. Upstream acceleration is sustained through a combination of mechanisms. However, both lateral stress and ice influx stabilize the ice stream. This study provides new insights into the ongoing changes occurring at Jakobshavn Isbræ and emphasizes that the incorporation of moving boundaries and dynamic lateral effects, not captured in flow-line models, is key for realistic model projections of sea level rise on centennial timescales.
    Keywords: Jakobshavn_Isbræ_drainage_basin; West Greenland
    Type: Dataset
    Format: application/zip, 469.2 MBytes
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  • 5
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    Band-pass-filtered ice-sheet surface elevation, thickness, velocity and derived data maps for the northern Greenland Ice Sheet (2018)
    PANGAEA
    In:  Supplement to: Bons, Paul D; Kleiner, Thomas; Llorens, Maria-Gema; Prior, David J; Sachau, Till; Weikusat, Ilka; Jansen, Daniela (2018): Greenland Ice Sheet: Higher Nonlinearity of Ice Flow Significantly Reduces Estimated Basal Motion. Geophysical Research Letters, 45(13), 6542-6548, https://doi.org/10.1029/2018GL078356
    Details
    Publication Date: 2023-02-06
    Description: In times of warming in polar regions, the prediction of ice sheet discharge is of utmost importance to society, because of its impact on sea level rise. In simulations the flow rate of ice is usually implemented as proportional to the differential stress to the power of the exponent n=3. This exponent influences the softness of the modeled ice, as higher values would produce faster flow under equal stress. We show that the stress exponent, which best fits the observed state of the Greenland Ice Sheet, equals n=4, Our results, which are not dependent on a possible basal sliding component of flow, indicate that most of the interior northern ice sheet is currently frozen to bedrock, except for the large ice streams and marginal ice.
    Keywords: File content; File format; File name; File size; MULT; Multiple investigations; Northern_Greenland_Ice_Sheet; Uniform resource locator/link to file
    Type: Dataset
    Format: text/tab-separated-values, 75 data points
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  • 6
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    Basal roughness in East Antarctica (2021)
    PANGAEA
    Details
    Publication Date: 2024-04-20
    Description: We provide a data set to investigate the subglacial properties of the East Antarctic Ice Sheet by statistically analysing the roughness of the bed topography, inferred from radio-echo sounding measurements. We analyse two sets of roughness parameters, one derived in the spatial and the other in the spectral domain, with two roughness parameters each. This enables us to compare the suitability of the four roughness parameters to classify the subglacial landscapes below the ice sheet.
    Keywords: Antarctica; bedrock; Binary Object; Binary Object (File Size); East_Antarctica; MULT; Multiple investigations; Radar Data; radio-echo sounding
    Type: Dataset
    Format: text/tab-separated-values, 14 data points
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