Calving Induced Speedup of Petermann Glacier

Abstract

This study assesses the response on ice dynamics of Petermann Glacier, a major outlet glacier in northern Greenland, to the 2012 and a possible future calving event. So far Petermann Glacier has been believed to be dynamically stable as another large calving event in 2010 had no significant impact on flow velocity or grounding line retreat. By analyzing a time series of remotely sensed surface velocities, we find an average acceleration of 10% between winter 2011/2012 and winter 2016/2017. This increase in surface velocity is not linear but can be separated into two parts, starting in 2012 and 2016 respectively. By conducting modeling experiments, we show that the first speedup can be directly connected to the 2012 calving event, while the second speedup is not captured. However, on recent remote sensing imagery newly developing fractures are clearly visible ∼12 km upstream from the terminus, propagating from the eastern fjord wall to the center of the ice tongue, indicating a possible future calving event. By including these fracture zones as a new terminus position in the modeling domain, we are able to reproduce the second speedup, suggesting that surface velocities remain on the 2016/2017 level after the anticipated calving event. This indicates that, from a dynamical point of view, the terminus region has already detached from the main ice tongue.

Sensitivity of Greenland ice sheet projections to spatial resolution in higher-order simulations: the Alfred Wegener Institute (AWI) contribution to ISMIP6 Greenland using the Ice-sheet and Sea-level System Model (ISSM)

“…Code and data availability. Simulation results on the native grids described in this paper will be made publicly available with a digital object identifier: https://doi.org/10.5281/zenodo.3992605 (Rückamp et al, 2020). The forcing data sets are available through (ISMIP6, 2015, http://www.climate-cryosphere.org/wiki/ index.php?title=ISMIP6_wiki_page, last access: 21 August 2020).…”

Sensitivity of Greenland ice sheet projections to spatial resolution in higher-order simulations: the AWI contribution to ISMIP6-Greenland using ISSM

“…It has been applied successfully to the GrIS in the past (Seroussi et al, 2013;Goelzer et al, 2018;Rückamp et al, 2018Rückamp et al, , 2019a and is also used for studies of individual drainage basins of Greenland, e.g. the North East Greenland Ice Stream (Choi et al, 2017), Jakobshavn Isbrae (Bondzio et al, 2017) and Petermann Glacier (Rückamp et al, 2019b).…”

“…The melt factor is roughly adjusted such that melting rates correspond to literature values (e.g. Wilson et al, 2017;Rückamp et al, 2019b). In this parameterization ocean temperature and salinity are set to −1.7 • C and 35 Psu, respectively.…”

Empirical Removal of Tides and Inverse Barometer Effect on DInSAR From Double DInSAR and a Regional Climate Model

“…Precise orbits are generated by the Copernicus Precise Orbit Determination Service. For topography, we use the Dronning Maud Land TanDEM-X DEM created by the Alfred-Wegener Institute [31]. If the atmospheric and noise phase components can be neglected or corrected [32], the differential phase obtained after removing the geometric component is retrieved, leading to direct estimation of the LOS displacement component.…”