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  - Levermann, Anders
A1  - Winkelmann, Ricarda
A1  - Nowicki, S.
A1  - Fastook, J. L.
A1  - Frieler, Katja
A1  - Greve, R.
A1  - Hellmer, H. H.
A1  - Martin, M. A.
A1  - Meinshausen, Malte
A1  - Mengel, Matthias
A1  - Payne, A. J.
A1  - Pollard, D.
A1  - Sato, T.
A1  - Timmermann, R.
A1  - Wang, Wei Li
A1  - Bindschadler, Robert A.
T1  - Projecting antarctic ice discharge using response functions from SeaRISE ice-sheet models
JF  - Earth system dynamics
N2  - The largest uncertainty in projections of future sea-level change results from the potentially changing dynamical ice discharge from Antarctica. Basal ice-shelf melting induced by a warming ocean has been identified as a major cause for additional ice flow across the grounding line. Here we attempt to estimate the uncertainty range of future ice discharge from Antarctica by combining uncertainty in the climatic forcing, the oceanic response and the ice-sheet model response. The uncertainty in the global mean temperature increase is obtained from historically constrained emulations with the MAGICC-6.0 (Model for the Assessment of Greenhouse gas Induced Climate Change) model. The oceanic forcing is derived from scaling of the subsurface with the atmospheric warming from 19 comprehensive climate models of the Coupled Model Intercomparison Project (CMIP-5) and two ocean models from the EU-project Ice2Sea. The dynamic ice-sheet response is derived from linear response functions for basal ice-shelf melting for four different Antarctic drainage regions using experiments from the Sea-level Response to Ice Sheet Evolution (SeaRISE) intercomparison project with five different Antarctic ice-sheet models. The resulting uncertainty range for the historic Antarctic contribution to global sea-level rise from 1992 to 2011 agrees with the observed contribution for this period if we use the three ice-sheet models with an explicit representation of ice-shelf dynamics and account for the time-delayed warming of the oceanic subsurface compared to the surface air temperature. The median of the additional ice loss for the 21st century is computed to 0.07 m (66% range: 0.02-0.14 m; 90% range: 0.0-0.23 m) of global sea-level equivalent for the low-emission RCP-2.6 (Representative Concentration Pathway) scenario and 0.09 m (66% range: 0.04-0.21 m; 90% range: 0.01-0.37 m) for the strongest RCP-8.5. Assuming no time delay between the atmospheric warming and the oceanic subsurface, these values increase to 0.09 m (66% range: 0.04-0.17 m; 90% range: 0.02-0.25 m) for RCP-2.6 and 0.15 m (66% range: 0.07-0.28 m; 90% range: 0.04-0.43 m) for RCP-8.5. All probability distributions are highly skewed towards high values. The applied ice-sheet models are coarse resolution with limitations in the representation of grounding-line motion. Within the constraints of the applied methods, the uncertainty induced from different ice-sheet models is smaller than that induced by the external forcing to the ice sheets.
Y1  - 2014
U6  - https://doi.org/10.5194/esd-5-271-2014
SN  - 2190-4979
SN  - 2190-4987
VL  - 5
IS  - 2
SP  - 271
EP  - 293
PB  - Copernicus
CY  - Göttingen
ER  -