An inter-comparison of the mass budget of the Arctic sea ice in CMIP6 models

• Published in: The Cryosphere
• Main Authors: Keen, Ann, Blockley, Ed, Bailey, David, Boldingh Debernard, Jens, Bushuk, Mitchell, Delhaye, Steve, Docquier, David, Feltham, Daniel, Massonnet, François, O'Farrell, Siobhan, Ponsoni, Leandro, Rodriguez, José M., Schroeder, David, Swart, Neil, Toyoda, Takahiro, Tsujino, Hiroyuki, Vancoppenolle, M., Wyser, Klaus
• Other Authors: Met Office Hadley Centre (MOHC), United Kingdom Met Office Exeter, National Center for Atmospheric Research Boulder (NCAR), Norwegian Meteorological Institute Oslo (MET), NOAA Geophysical Fluid Dynamics Laboratory (GFDL), National Oceanic and Atmospheric Administration (NOAA), Centre Georges Lemaître for Earth and Climate Research Louvain (TECLIM), Earth and Life Institute Louvain-La-Neuve (ELI), Université Catholique de Louvain = Catholic University of Louvain (UCL)-Université Catholique de Louvain = Catholic University of Louvain (UCL), Rossby Centre, SMHI, Norrköping, 601 76, Sweden, Swedish Meteorological and Hydrological Institute (SMHI), Centre for Polar Observation and Modelling (CPOM), Natural Environment Research Council (NERC), CISRO Oceans and Atmosphere, Agencia Estatal de Meteorología (AEMet), Environment and Climate Change Canada (ECCC), Meteorological Research Institute Tsukuba (MRI), Japan Meteorological Agency (JMA), Nucleus for European Modeling of the Ocean (NEMO R&D ), Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques (LOCEAN), Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS-PSL), Université Paris Sciences et Lettres (PSL)-Université Paris Sciences et Lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales Toulouse (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-École normale supérieure - Paris (ENS-PSL), Université Paris Sciences et Lettres (PSL)-Université Paris Sciences et Lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National d'Études Spatiales Toulouse (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), Université Paris Sciences et Lettres (PSL)-Université Paris Sciences et Lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National d'Études Spatiales Toulouse (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), European Project: 641727,H2020,H2020-SC5-2014-two-stage,PRIMAVERA(2015), European Project: 0834493(2008)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2021
• Subjects: [PHYS.PHYS.PHYS-GEO-PH]Physics [physics]/Physics [physics]/Geophysics [physics.geo-ph]; Arctic; Sea ice; The Cryosphere
• Online Access: https://hal.science/hal-03244580; https://hal.science/hal-03244580/document; https://hal.science/hal-03244580/file/tc-15-951-2021.pdf; https://doi.org/10.5194/tc-15-951-2021

International audience We compare the mass budget of the Arctic sea ice for 15 models submitted to the latest Coupled Model Intercomparison Project (CMIP6), using new diagnostics that have not been available for previous model inter-comparisons. These diagnostics allow us to look beyond the standard metrics of ice cover and thickness to compare the processes of sea ice growth and loss in climate models in a more detailed way than has previously been possible. For the 1960–1989 multi-model mean, the dominant processes causing annual ice growth are basal growth and frazil ice formation, which both occur during the winter. The main processes by which ice is lost are basal melting, top melting and advection of ice out of the Arctic. The first two processes occur in summer, while the latter process is present all year. The sea ice budgets for individual models are strikingly similar overall in terms of the major processes causing ice growth and loss and in terms of the time of year during which each process is important. However, there are also some key differences between the models, and we have found a number of relationships between model formulation and components of the ice budget that hold for all or most of the CMIP6 models considered here. The relative amounts of frazil and basal ice formation vary between the models, and the amount of frazil ice formation is strongly dependent on the value chosen for the minimum frazil ice thickness. There are also differences in the relative amounts of top and basal melting, potentially dependent on how much shortwave radiation can penetrate through the sea ice into the ocean. For models with prognostic melt ponds, the choice of scheme may affect the amount of basal growth, basal melt and top melt, and the choice of thermodynamic scheme is important in determining the amount of basal growth and top melt. As the ice cover and mass decline during the 21st century, we see a shift in the timing of the top and basal melting in the multi-model mean, with more melt occurring ...