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  - 
TY  - JOUR
A1  - Seroussi, Helene
A1  - Nowicki, Sophie
A1  - Payne, Antony J.
A1  - Goelzer, Heiko
A1  - Lipscomb, William H.
A1  - Abe-Ouchi, Ayako
A1  - Agosta, Cecile
A1  - Albrecht, Torsten
A1  - Asay-Davis, Xylar
A1  - Barthel, Alice
A1  - Calov, Reinhard
A1  - Cullather, Richard
A1  - Dumas, Christophe
A1  - Galton-Fenzi, Benjamin K.
A1  - Gladstone, Rupert
A1  - Golledge, Nicholas R.
A1  - Gregory, Jonathan M.
A1  - Greve, Ralf
A1  - Hattermann, Tore
A1  - Hoffman, Matthew J.
A1  - Humbert, Angelika
A1  - Huybrechts, Philippe
A1  - Jourdain, Nicolas C.
A1  - Kleiner, Thomas
A1  - Larour, Eric
A1  - Leguy, Gunter R.
A1  - Lowry, Daniel P.
A1  - Little, Chistopher M.
A1  - Morlighem, Mathieu
A1  - Pattyn, Frank
A1  - Pelle, Tyler
A1  - Price, Stephen F.
A1  - Quiquet, Aurelien
A1  - Reese, Ronja
A1  - Schlegel, Nicole-Jeanne
A1  - Shepherd, Andrew
A1  - Simon, Erika
A1  - Smith, Robin S.
A1  - Straneo, Fiammetta
A1  - Sun, Sainan
A1  - Trusel, Luke D.
A1  - Van Breedam, Jonas
A1  - van de Wal, Roderik S. W.
A1  - Winkelmann, Ricarda
A1  - Zhao, Chen
A1  - Zhang, Tong
A1  - Zwinger, Thomas
T1  - ISMIP6 Antarctica
BT  - a multi-model ensemble of the Antarctic ice sheet evolution over the 21st century
JF  - The Cryosphere : TC ; an interactive open access journal of the European Geosciences Union
N2  - Ice flow models of the Antarctic ice sheet are commonly used to simulate its future evolution in response to different climate scenarios and assess the mass loss that would contribute to future sea level rise. However, there is currently no consensus on estimates of the future mass balance of the ice sheet, primarily because of differences in the representation of physical processes, forcings employed and initial states of ice sheet models. This study presents results from ice flow model simulations from 13 international groups focusing on the evolution of the Antarctic ice sheet during the period 2015-2100 as part of the Ice Sheet Model Intercomparison for CMIP6 (ISMIP6). They are forced with outputs from a subset of models from the Coupled Model Intercomparison Project Phase 5 (CMIP5), representative of the spread in climate model results. Simulations of the Antarctic ice sheet contribution to sea level rise in response to increased warming during this period varies between 7:8 and 30.0 cm of sea level equivalent (SLE) under Representative Concentration Pathway (RCP) 8.5 scenario forcing. These numbers are relative to a control experiment with constant climate conditions and should therefore be added to the mass loss contribution under climate conditions similar to present-day conditions over the same period. The simulated evolution of the West Antarctic ice sheet varies widely among models, with an overall mass loss, up to 18.0 cm SLE, in response to changes in oceanic conditions. East Antarctica mass change varies between 6 :1 and 8.3 cm SLE in the simulations, with a significant increase in surface mass balance outweighing the increased ice discharge under most RCP 8.5 scenario forcings. The inclusion of ice shelf collapse, here assumed to be caused by large amounts of liquid water ponding at the surface of ice shelves, yields an additional simulated mass loss of 28mm compared to simulations without ice shelf collapse. The largest sources of uncertainty come from the climate forcing, the ocean-induced melt rates, the calibration of these melt rates based on oceanic conditions taken outside of ice shelf cavities and the ice sheet dynamic response to these oceanic changes. Results under RCP 2.6 scenario based on two CMIP5 climate models show an additional mass loss of 0 and 3 cm of SLE on average compared to simulations done under present-day conditions for the two CMIP5 forcings used and display limited mass gain in East Antarctica.
Y1  - 2020
U6  - https://doi.org/10.5194/tc-14-3033-2020
SN  - 1994-0416
SN  - 1994-0424
VL  - 14
IS  - 9
SP  - 3033
EP  - 3070
PB  - Copernicus
CY  - Göttingen
ER  - 
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  - Bindschadler, Robert A.
A1  - Nowicki, Sophie
A1  - Abe-Ouchi, Ayako
A1  - Aschwanden, Andy
A1  - Choi, Hyeungu
A1  - Fastook, Jim
A1  - Granzow, Glen
A1  - Greve, Ralf
A1  - Gutowski, Gail
A1  - Herzfeld, Ute
A1  - Jackson, Charles
A1  - Johnson, Jesse
A1  - Khroulev, Constantine
A1  - Levermann, Anders
A1  - Lipscomb, William H.
A1  - Martin, Maria A.
A1  - Morlighem, Mathieu
A1  - Parizek, Byron R.
A1  - Pollard, David
A1  - Price, Stephen F.
A1  - Ren, Diandong
A1  - Saito, Fuyuki
A1  - Sato, Tatsuru
A1  - Seddik, Hakime
A1  - Seroussi, Helene
A1  - Takahashi, Kunio
A1  - Walker, Ryan
A1  - Wang, Wei Li
T1  - Ice-sheet model sensitivities to environmental forcing and their use in projecting future sea level (the SeaRISE project)
JF  - Journal of glaciology
N2  - Ten ice-sheet models are used to study sensitivity of the Greenland and Antarctic ice sheets to prescribed changes of surface mass balance, sub-ice-shelf melting and basal sliding. Results exhibit a large range in projected contributions to sea-level change. In most cases, the ice volume above flotation lost is linearly dependent on the strength of the forcing. Combinations of forcings can be closely approximated by linearly summing the contributions from single forcing experiments, suggesting that nonlinear feedbacks are modest. Our models indicate that Greenland is more sensitive than Antarctica to likely atmospheric changes in temperature and precipitation, while Antarctica is more sensitive to increased ice-shelf basal melting. An experiment approximating the Intergovernmental Panel on Climate Change's RCP8.5 scenario produces additional first-century contributions to sea level of 22.3 and 8.1 cm from Greenland and Antarctica, respectively, with a range among models of 62 and 14 cm, respectively. By 200 years, projections increase to 53.2 and 26.7 cm, respectively, with ranges of 79 and 43 cm. Linear interpolation of the sensitivity results closely approximates these projections, revealing the relative contributions of the individual forcings on the combined volume change and suggesting that total ice-sheet response to complicated forcings over 200 years can be linearized.
Y1  - 2013
U6  - https://doi.org/10.3189/2013JoG12J125
SN  - 0022-1430
VL  - 59
IS  - 214
SP  - 195
EP  - 224
PB  - International Glaciological Society
CY  - Cambridge
ER  - 
TY  - JOUR
A1  - Nowicki, Sophie
A1  - Bindschadler, Robert A.
A1  - Abe-Ouchi, Ayako
A1  - Aschwanden, Andy
A1  - Bueler, Ed
A1  - Choi, Hyeungu
A1  - Fastook, Jim
A1  - Granzow, Glen
A1  - Greve, Ralf
A1  - Gutowski, Gail
A1  - Herzfeld, Ute
A1  - Jackson, Charles
A1  - Johnson, Jesse
A1  - Khroulev, Constantine
A1  - Larour, Eric
A1  - Levermann, Anders
A1  - Lipscomb, William H.
A1  - Martin, Maria A.
A1  - Morlighem, Mathieu
A1  - Parizek, Byron R.
A1  - Pollard, David
A1  - Price, Stephen F.
A1  - Ren, Diandong
A1  - Rignot, Eric
A1  - Saito, Fuyuki
A1  - Sato, Tatsuru
A1  - Seddik, Hakime
A1  - Seroussi, Helene
A1  - Takahashi, Kunio
A1  - Walker, Ryan
A1  - Wang, Wei Li
T1  - Insights into spatial sensitivities of ice mass response to environmental change from the SeaRISE ice sheet modeling project II  Greenland
JF  - Journal of geophysical research : Earth surface
N2  - The Sea-level Response to Ice Sheet Evolution (SeaRISE) effort explores the sensitivity of the current generation of ice sheet models to external forcing to gain insight into the potential future contribution to sea level from the Greenland and Antarctic ice sheets. All participating models simulated the ice sheet response to three types of external forcings: a change in oceanic condition, a warmer atmospheric environment, and enhanced basal lubrication. Here an analysis of the spatial response of the Greenland ice sheet is presented, and the impact of model physics and spin-up on the projections is explored. Although the modeled responses are not always homogeneous, consistent spatial trends emerge from the ensemble analysis, indicating distinct vulnerabilities of the Greenland ice sheet. There are clear response patterns associated with each forcing, and a similar mass loss at the full ice sheet scale will result in different mass losses at the regional scale, as well as distinct thickness changes over the ice sheet. All forcings lead to an increased mass loss for the coming centuries, with increased basal lubrication and warmer ocean conditions affecting mainly outlet glaciers, while the impacts of atmospheric forcings affect the whole ice sheet.
KW  - Greenland
KW  - ice-sheet
KW  - sea-level
KW  - model
KW  - ensemble
Y1  - 2013
U6  - https://doi.org/10.1002/jgrf.20076
SN  - 2169-9003
VL  - 118
IS  - 2
SP  - 1025
EP  - 1044
PB  - American Geophysical Union
CY  - Washington
ER  -