@article {Goelzer2018, title = {{Design and results of the ice sheet model initialisation experiments initMIP-Greenland: an ISMIP6 intercomparison}}, journal = {The Cryosphere}, volume = {12}, number = {4}, year = {2018}, month = {apr}, pages = {1433{\textendash}1460}, abstract = {Abstract. Earlier large-scale Greenland ice sheet sea-level projections (e.g. those run during the ice2sea and SeaRISE initiatives) have shown that ice sheet initial conditions have a large effect on the projections and give rise to important uncertainties. The goal of this initMIP-Greenland intercomparison exercise is to compare, evaluate, and improve the initialisation techniques used in the ice sheet modelling community and to estimate the associated uncertainties in modelled mass changes. initMIP-Greenland is the first in a series of ice sheet model intercomparison activities within ISMIP6 (the Ice Sheet Model Intercomparison Project for CMIP6), which is the primary activity within the Coupled Model Intercomparison Project Phase 6 (CMIP6) focusing on the ice sheets. Two experiments for the large-scale Greenland ice sheet have been designed to allow intercomparison between participating models of (1) the initial present-day state of the ice sheet and (2) the response in two idealised forward experiments. The forward experiments serve to evaluate the initialisation in terms of model drift (forward run without additional forcing) and in response to a large perturbation (prescribed surface mass balance anomaly); they should not be interpreted as sea-level projections. We present and discuss results that highlight the diversity of data sets, boundary conditions, and initialisation techniques used in the community to generate initial states of the Greenland ice sheet. We find good agreement across the ensemble for the dynamic response to surface mass balance changes in areas where the simulated ice sheets overlap but differences arising from the initial size of the ice sheet. The model drift in the control experiment is reduced for models that participated in earlier intercomparison exercises.}, issn = {1994-0424}, doi = {10.5194/tc-12-1433-2018}, url = {https://www.the-cryosphere.net/12/1433/2018/}, author = {Goelzer, Heiko and Nowicki, Sophie and Edwards, Tamsin and Beckley, Matthew and Abe-Ouchi, Ayako and Aschwanden, Andy and Calov, Reinhard and Gagliardini, Olivier and Gillet-Chaulet, Fabien and Golledge, Nicholas R. and Gregory, Jonathan and Greve, Ralf and Humbert, Angelika and Huybrechts, Philippe and Kennedy, Joseph H. and Larour, Eric and Lipscomb, William H. and Le clec\'h, S{\'e}bastien and Lee, Victoria and Morlighem, Mathieu and Pattyn, Frank and Payne, Antony J. and Rodehacke, Christian and R{\"u}ckamp, Martin and Saito, Fuyuki and Schlegel, Nicole and Seroussi, Helene and Shepherd, Andrew and Sun, Sainan and van de Wal, Roderik and Ziemen, Florian A.} } @article {Kiaer2018, title = {{A large impact crater beneath Hiawatha Glacier in northwest Greenland}}, journal = {Science Advances}, volume = {4}, number = {11}, year = {2018}, month = {nov}, pages = {eaar8173}, abstract = {We report the discovery of a large impact crater beneath Hiawatha Glacier in northwest Greenland. From airborne radar surveys, we identify a 31-kilometer-wide, circular bedrock depression beneath up to a kilometer of ice. This depression has an elevated rim that cross-cuts tributary subglacial channels and a subdued central uplift that appears to be actively eroding. From ground investigations of the deglaciated foreland, we identify overprinted structures within Precambrian bedrock along the ice margin that strike tangent to the subglacial rim. Glaciofluvial sediment from the largest river draining the crater contains shocked quartz and other impact-related grains. Geochemical analysis of this sediment indicates that the impactor was a fractionated iron asteroid, which must have been more than a kilometer wide to produce the identified crater. Radiostratigraphy of the ice in the crater shows that the Holocene ice is continuous and conformable, but all deeper and older ice appears to be debris rich or heavily disturbed. The age of this impact crater is presently unknown, but from our geological and geophysical evidence, we conclude that it is unlikely to predate the Pleistocene inception of the Greenland Ice Sheet.}, issn = {23752548}, doi = {10.1126/sciadv.aar8173}, url = {http://advances.sciencemag.org/ http://advances.sciencemag.org/lookup/doi/10.1126/sciadv.aar8173}, author = {Kj{\ae}r, Kurt H. and Larsen, Nicolaj K and Binder, Tobias and Bj{\o}rk, Anders A and Eisen, Olaf and Fahnestock, Mark A and Funder, Svend and Garde, Adam A and Haack, Henning and Helm, Veit and Houmark-Nielsen, Michael and Kjeldsen, Kristian K and Khan, Shfaqat A and Machguth, Horst and McDonald, Iain and Morlighem, Mathieu and Mouginot, J{\'e}r{\'e}mie and Paden, John D and Waight, Tod E and Weikusat, Christian and Willerslev, Eske and MacGregor, Joseph A.} } @article {MacGregor2016a, title = {{A synthesis of the basal thermal state of the Greenland Ice Sheet}}, journal = {Journal of Geophysical Research: Earth Surface}, year = {2016}, month = {jul}, issn = {21699003}, url = {http://doi.wiley.com/10.1002/2015JF003803}, author = {MacGregor, Joseph A. and Fahnestock, Mark A. and Catania, Ginny A. and Aschwanden, Andy and Clow, Gary D. and Colgan, William T. and Gogineni, S. Prasad and Morlighem, Mathieu and Nowicki, Sophie M. J. and Paden, John D. and Price, Stephen F. and Seroussi, Helene} } @article {MacGregor2015b, title = {{Radar attenuation and temperature within the Greenland Ice Sheet}}, journal = {Journal of Geophysical Research: Earth Surface}, volume = {120}, number = {6}, year = {2015}, month = {jun}, pages = {983{\textendash}1008}, issn = {21699003}, doi = {10.1002/2014JF003418}, url = {http://doi.wiley.com/10.1002/2014JF003418}, author = {MacGregor, Joseph A. and Li, Jilu and Paden, John D and Catania, Ginny a and Clow, Gary D and Fahnestock, Mark A and Gogineni, S Prasad and Grimm, Robert E and Morlighem, Mathieu and Nandi, Soumyaroop and Seroussi, Helene and Stillman, David E} } @article {MacGregor2015, title = {{Radiostratigraphy and age structure of the Greenland Ice Sheet}}, journal = {Journal of Geophysical Research: Earth Surface}, volume = {120}, year = {2015}, pages = {212{\textendash}241}, keywords = {10.1002/2014JF003215 and Greenland Ice Sheet, ice core, ice-penetrating dynamics, ice-sheet dynamics}, issn = {21699003}, doi = {10.1002/2014JF003215}, url = {http://doi.wiley.com/10.1002/2014JF003215}, author = {MacGregor, Joseph A. and Fahnestock, Mark A. and Catania, Ginny A. and Paden, John D and Prasad Gogineni, S. and Young, S Keith and Rybarski, Susan C and Mabrey, Alexandria N and Wagman, Benjamin M and Morlighem, Mathieu} } @article {SeariseAntarctica2013, title = {{Insights into spatial sensitivities of ice mass response to environmental change from the SeaRISE ice sheet modeling project I: Antarctica}}, journal = {J. Geophys. Res.}, volume = {118}, number = {2}, year = {2013}, pages = {1002{\textendash}1024}, issn = {21699003}, doi = {10.1002/jgrf.20081}, url = {http://doi.wiley.com/10.1002/jgrf.20081}, author = {Nowicki, Sophie and Robert A. Bindschadler and Abe-Ouchi, Ayako and Andy Aschwanden and E. Bueler and Choi, Hyeungu and Fastook, Jim and Granzow, Glen and Greve, Ralf and Gutowski, Gail and Herzfeld, Ute and Jackson, Charles and Jesse V Johnson and Constantine Khroulev and Larour, Eric and Anders Levermann and Lipscomb, William H. and Maria A. Martin and Morlighem, Mathieu and Parizek, Byron R. and David Pollard and Stephen F. Price and Ren, Diandong and Eric Rignot and Fuyuki Saito and Tatsuru Sato and Seddik, Hakime and Seroussi, Helene and Takahashi, Kunio and Walker, Ryan and Wang, Wei Li} } @article {SeariseGreenland2013, title = {{Insights into spatial sensitivities of ice mass response to environmental change from the SeaRISE ice sheet modeling project II: Greenland}}, journal = {J. Geophys. Res.}, volume = {118}, number = {2}, year = {2013}, month = {jun}, pages = {1025{\textendash}1044}, issn = {21699003}, doi = {10.1002/jgrf.20076}, url = {http://doi.wiley.com/10.1002/jgrf.20076}, author = {Nowicki, Sophie and Robert A. Bindschadler and Abe-Ouchi, Ayako and Andy Aschwanden and E. Bueler and Choi, Hyeungu and Fastook, Jim and Granzow, Glen and Greve, Ralf and Gutowski, Gail and Herzfeld, Ute and Jackson, Charles and Jesse V Johnson and Constantine Khroulev and Larour, Eric and Anders Levermann and Lipscomb, William H. and Maria A. Martin and Morlighem, Mathieu and Parizek, Byron R. and David Pollard and Stephen F. Price and Ren, Diandong and Eric Rignot and Fuyuki Saito and Tatsuru Sato and Seddik, Hakime and Seroussi, Helene and Takahashi, Kunio and Walker, Ryan and Wang, Wei Li} }