Design and results of the ice sheet model initialisation experiments initMIP-Greenland: an ISMIP6 intercomparison

• Published in: The Cryosphere
• Main Authors: Goelzer, Heiko, Nowicki, Sophie, Edwards, Tamsin, Beckley, Matthew, Abe-Ouchi, Ayako, Aschwanden, Andy, Calov, Reinhard, Gagliardini, Olivier, Gillet-Chaulet, Fabien, Golledge, Nicholas, Gregory, Jonathan, Greve, Ralf, Humbert, Angelika, Huybrechts, Philippe, Kennedy, Joseph, Larour, Eric, Lipscomb, William, Le Clech, Sébastien, Lee, Victoria, Morlighem, Mathieu, Pattyn, Frank, Payne, Antony, Rodehacke, Christian, Rückamp, Martin, Saito, Fuyuki, Schlegel, Nicole, Seroussi, Hélène, Shepherd, Andrew, Sun, Sainan, van de Wal, Roderik, S W, Ziemen, Florian
• Other Authors: Center for Climate System Research Kashiwa (CCSR), The University of Tokyo (UTokyo), Institut des Géosciences de l’Environnement (IGE), Institut de Recherche pour le Développement (IRD)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes 2016-2019 (UGA 2016-2019 ), Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), Laboratoire des Sciences du Climat et de l'Environnement Gif-sur-Yvette (LSCE), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), University of California Irvine (UC Irvine), University of California (UC), Université libre de Bruxelles (ULB), Laboratoire de mécanique des sols, structures et matériaux (MSSMat), CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), School of Earth and Environment Leeds (SEE), University of Leeds, Institute for Marine and Atmospheric Research Utrecht (IMAU), Universiteit Utrecht / Utrecht University Utrecht
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2018
• Subjects: [SDU.OCEAN]Sciences of the Universe [physics]/Ocean; Atmosphere; [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces; environment; Greenland; Ice Sheet; The Cryosphere
• Online Access: https://hal.science/hal-01806753; https://hal.science/hal-01806753/document; https://hal.science/hal-01806753/file/tc-12-1433-2018.pdf; https://doi.org/10.5194/tc-12-1433-2018

International audience 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 intercom-parison exercise is to compare, evaluate, and improve the ini-tialisation 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 Intercom-parison 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.