TY  - JOUR
A1  - Seroussi, Helene
A1  - Nowicki, Sophie
A1  - Simon, Erika
A1  - Abe-Ouchi, Ayako
A1  - Albrecht, Torsten
A1  - Brondex, Julien
A1  - Cornford, Stephen
A1  - Dumas, Christophe
A1  - Gillet-Chaulet, Fabien
A1  - Goelzer, Heiko
A1  - Golledge, Nicholas R.
A1  - Gregory, Jonathan M.
A1  - Greve, Ralf
A1  - Hoffman, Matthew J.
A1  - Humbert, Angelika
A1  - Huybrechts, Philippe
A1  - Kleiner, Thomas
A1  - Larourl, Eric
A1  - Leguy, Gunter
A1  - Lipscomb, William H.
A1  - Lowry, Daniel
A1  - Mengel, Matthias
A1  - Morlighem, Mathieu
A1  - Pattyn, Frank
A1  - Payne, Anthony J.
A1  - Pollard, David
A1  - Price, Stephen F.
A1  - Quiquet, Aurelien
A1  - Reerink, Thomas J.
A1  - Reese, Ronja
A1  - Rodehacke, Christian B.
A1  - Schlegel, Nicole-Jeanne
A1  - Shepherd, Andrew
A1  - Sun, Sainan
A1  - Sutter, Johannes
A1  - Van Breedam, Jonas
A1  - van de Wal, Roderik S. W.
A1  - Winkelmann, Ricarda
A1  - Zhang, Tong
T1  - initMIP-Antarctica
BT  - an ice sheet model initialization experiment of ISMIP6
JF  - The Cryosphere : TC ; an interactive open access journal of the European Geosciences Union
N2  - Ice sheet numerical modeling is an important tool to estimate the dynamic contribution of the Antarctic ice sheet to sea level rise over the coming centuries. The influence of initial conditions on ice sheet model simulations, however, is still unclear. To better understand this influence, an initial state intercomparison exercise (initMIP) has been developed to compare, evaluate, and improve initialization procedures and estimate their impact on century-scale simulations. initMlP is the first set of experiments of the Ice Sheet Model Intercomparison Project for CMIP6 (ISMIP6), which is the primary Coupled Model Intercomparison Project Phase 6 (CMIP6) activity focusing on the Greenland and Antarctic ice sheets. Following initMlP-Greenland, initMlP-Antarctica has been designed to explore uncertainties associated with model initialization and spin-up and to evaluate the impact of changes in external forcings. Starting from the state of the Antarctic ice sheet at the end of the initialization procedure, three forward experiments are each run for 100 years: a control run, a run with a surface mass balance anomaly, and a run with a basal melting anomaly beneath floating ice. This study presents the results of initMlP-Antarctica from 25 simulations performed by 16 international modeling groups. The submitted results use different initial conditions and initialization methods, as well as ice flow model parameters and reference external forcings. We find a good agreement among model responses to the surface mass balance anomaly but large variations in responses to the basal melting anomaly. These variations can be attributed to differences in the extent of ice shelves and their upstream tributaries, the numerical treatment of grounding line, and the initial ocean conditions applied, suggesting that ongoing efforts to better represent ice shelves in continental-scale models should continue.
Y1  - 2019
U6  - https://doi.org/10.5194/tc-13-1441-2019
SN  - 1994-0416
SN  - 1994-0424
VL  - 13
IS  - 5
SP  - 1441
EP  - 1471
PB  - Copernicus
CY  - Göttingen
ER  - 
TY  - JOUR
A1  - Pattyn, Frank
A1  - Perichon, Laura
A1  - Durand, Gael
A1  - Favier, Lionel
A1  - Gagliardini, Olivier
A1  - Hindmarsh, Richard C. A.
A1  - Zwinger, Thomas
A1  - Albrecht, Torsten
A1  - Cornford, Stephen
A1  - Docquier, David
A1  - Furst, Johannes J.
A1  - Goldberg, Daniel
A1  - Gudmundsson, Gudmundur Hilmar
A1  - Humbert, Angelika
A1  - Huetten, Moritz
A1  - Huybrechts, Philippe
A1  - Jouvet, Guillaume
A1  - Kleiner, Thomas
A1  - Larour, Eric
A1  - Martin, Daniel
A1  - Morlighem, Mathieu
A1  - Payne, Anthony J.
A1  - Pollard, David
A1  - Rueckamp, Martin
A1  - Rybak, Oleg
A1  - Seroussi, Helene
A1  - Thoma, Malte
A1  - Wilkens, Nina
T1  - Grounding-line migration in plan-view marine ice-sheet models: results of the ice2sea MISMIP3d intercomparison
JF  - Journal of glaciology
N2  - Predictions of marine ice-sheet behaviour require models able to simulate grounding-line migration. We present results of an intercomparison experiment for plan-view marine ice-sheet models. Verification is effected by comparison with approximate analytical solutions for flux across the grounding line using simplified geometrical configurations (no lateral variations, no buttressing effects from lateral drag). Perturbation experiments specifying spatial variation in basal sliding parameters permitted the evolution of curved grounding lines, generating buttressing effects. The experiments showed regions of compression and extensional flow across the grounding line, thereby invalidating the boundary layer theory. Steady-state grounding-line positions were found to be dependent on the level of physical model approximation. Resolving grounding lines requires inclusion of membrane stresses, a sufficiently small grid size (<500 m), or subgrid interpolation of the grounding line. The latter still requires nominal grid sizes of <5 km. For larger grid spacings, appropriate parameterizations for ice flux may be imposed at the grounding line, but the short-time transient behaviour is then incorrect and different from models that do not incorporate grounding-line parameterizations. The numerical error associated with predicting grounding-line motion can be reduced significantly below the errors associated with parameter ignorance and uncertainties in future scenarios.
Y1  - 2013
U6  - https://doi.org/10.3189/2013JoG12J129
SN  - 0022-1430
VL  - 59
IS  - 215
SP  - 410
EP  - 422
PB  - International Glaciological Society
CY  - Cambridge
ER  -