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Some notes related to the CICE5 implementation in ESM1.6 . This is a very short summary of the CICE5 configuration for esm1.6, the main reference will be the not-yet-written paper
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Co-authored-by: Claire Carouge <ccarouge@users.noreply.github.com>
Co-authored-by: blimlim <blimlim@users.noreply.github.com>
In ACCESS-ESM1.6, the sea ice component is CICE5 [@hunke2015cice] updated from CICE4 used in ACCESS-ESM1.5.
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Scientifically the sea ice model is configured the same as ESM1.5 [@Ziehn2020]. The scientific configuration is summarised as follows:
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- Zero-layer thermodynamics [@Semtner1976]
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- One layer of snow and one layer of ice
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- UM calculates ice surface temperature, and conductive heat flux into the sea-ice
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- Ice transport [@Lipscomb2001] and ridging [@Rothrock1975]
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- Internal Ice Stress follow EVP [@Hunke2002]
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There are significant improvements to diagnostics to support CMIP style diagnostics [@notz_cmip6_2016][@egusphere-2025-3083] natively and error handling.
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## Meltwater Runoff
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Like ESM1.5, the OASIS3-MCT coupler is used and the sea ice model acts as the interface between the atmosphere and ocean models. The only significant change to this interface since ESM1.5 is changes to meltwater from Antarctica and Greenland. In all models in ACCESS 1-2 generations, there is no ice sheet model and the snow accumulates over each ice sheet. When the snow thickness is greater than 1100m, the snow volume is added to the river scheme and flows to the coast over a relatively short timescale (~7 days). The volume of meltwater discharge from Antarctica and Greenland is therefore equal to the recent snowfall over each continent. In ESM1.6, this meltwater is partially discharged at the coastline of each continent (to represent ice shelf basal melt) and partially spread in open ocean (to represent melt from icebergs). In ESM1.5 all meltwater is at the coastlines. In addition, the latent heat to melt this water is now taken from the ocean. Meltwater runoff is configured in the `input_ice.nml` [namelist](https://github.com/ACCESS-NRI/access-esm1.6-configs/blob/dev-preindustrial%2Bconcentrations/ice/input_ice.nml#L14-L25) with a prescribed pattern from the [`lice_discharge_iceberg.nc`](https://github.com/ACCESS-NRI/access-esm1.6-configs/blob/13cc7d229b0d4bda193879b8b30cde3441d61bec/config.yaml#L98) input file.
AUTHOR = {Fox-Kemper, B. and DeRepentigny, P. and Treguier, A. M. and Stepanek, C. and O'Rourke, E. and Mackallah, C. and Meucci, A. and Aksenov, Y. and Durack, P. J. and Feldl, N. and Hernaman, V. and Heuz\'e, C. and Iovino, D. and Madan, G. and Marquez, A. L. and Massonnet, F. and Mecking, J. and Samanta, D. and Taylor, P. C. and Tseng, W.-L. and Vancoppenolle, M.},
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TITLE = {CMIP7 Data Request: Ocean and Sea Ice Priorities and Opportunities},
abstract = {In sea ice models with multiple thickness categories the ice thickness distribution evolves in time. The evolution of the thickness distribution as ice grows and melts is analogous to one-dimensional fluid transport and can be treated by similar numerical methods. One such method, remapping, is applied here. Thickness categories are represented as Lagrangian grid cells whose boundaries are projected forward in time. The thickness distribution is approximated as a linear or quadratic polynomial in each displaced category, and ice area and volume are transferred between categories so as to restore the original boundaries. In simple test problems and in a single-column model with forcing typical of the central Arctic, remapping performs significantly better than methods previously used in sea ice models. It is less diffusive than a scheme that fixes the ice thickness in each category and behaves better numerically than a scheme that represents the thickness distribution as a set of delta functions. Also, remapping converges faster (i.e., with fewer thickness categories) than the alternative schemes. With five to seven categories the errors due to finite resolution of the thickness distribution are much smaller than the errors due to other sources. Linear remapping performs as well as the more complex quadratic version and is recommended for climate modeling. Its computational cost is minimal compared to other sea ice model components.},
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year = {2001}
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}
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@article{notz_cmip6_2016,
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title = {The {CMIP6} {Sea}-{Ice} {Model} {Intercomparison} {Project} ({SIMIP}): understanding sea ice through climate-model simulations},
abstract = {Abstract. A better understanding of the role of sea ice for the changing climate of our planet is the central aim of the diagnostic Coupled Model Intercomparison Project 6 (CMIP6)-endorsed Sea-Ice Model Intercomparison Project (SIMIP). To reach this aim, SIMIP requests sea-ice-related variables from climate-model simulations that allow for a better understanding and, ultimately, improvement of biases and errors in sea-ice simulations with large-scale climate models. This then allows us to better understand to what degree CMIP6 model simulations relate to reality, thus improving our confidence in answering sea-ice-related questions based on these simulations. Furthermore, the SIMIP protocol provides a standard for sea-ice model output that will streamline and hence simplify the analysis of the simulated sea-ice evolution in research projects independent of CMIP. To reach its aims, SIMIP provides a structured list of model output that allows for an examination of the three main budgets that govern the evolution of sea ice, namely the heat budget, the momentum budget, and the mass budget. In this contribution, we explain the aims of SIMIP in more detail and outline how its design allows us to answer some of the most pressing questions that sea ice still poses to the international climate-research community.},
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language = {en},
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number = {9},
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urldate = {2024-04-30},
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journal = {Geoscientific Model Development},
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author = {Notz, Dirk and Jahn, Alexandra and Holland, Marika and Hunke, Elizabeth and Massonnet, François and Stroeve, Julienne and Tremblay, Bruno and Vancoppenolle, Martin},
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month = sep,
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year = {2016},
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pages = {3427--3446},
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file = {Notz et al. - 2016 - The CMIP6 Sea-Ice Model Intercomparison Project (S.pdf:/Users/ajs/Zotero/storage/8RIWRH4M/Notz et al. - 2016 - The CMIP6 Sea-Ice Model Intercomparison Project (S.pdf:application/pdf},
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}
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@article{Rothrock1975,
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author = {Rothrock, D. A.},
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title = {The steady drift of an incompressible Arctic ice cover},
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journal = {Journal of Geophysical Research (1896-1977)},
abstract = {The steady drift of pack ice in an idealized arctic basin has been calculated by assuming that the ice is incompressible and inviscid. The momentum and continuity equations for the ice are solved for the velocity and the ice pressure. The divergence of velocity is assumed to be 0.33×10−8 s−1. The boundary conditions require that no ice flows across coastal boundaries but that ice flows out of the basin into the Greenland Sea and into the basin from the Kara Sea. The patterns of calculated velocities and vorticities are realistic, but their magnitudes are too high. The maximum calculated ice pressure of about 108 dyn cm−1 (pressure integrated through the ice thickness) is marginally able to ridge thick ice, according to the ridging model of Parmerter and Coon (1973). These maximum values occur near Greenland, where Wittmann and Schule (1966) report intense ridging. When the wind stress is reduced to one third of the strength first assumed, realistic speeds and vorticities are obtained, and the maximum pressures are reduced to one third of the above value. Coastal shear zones of the order of 100 km wide can be represented by the added assumption of a shear viscosity of about 6×1012 g s−1 and a no-slip condition on coastal boundaries.},
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year = {1975}
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}
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@article {Semtner1976,
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author = "Albert J. Semtner ",
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title = "A Model for the Thermodynamic Growth of Sea Ice in Numerical Investigations of Climate",
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journal = "Journal of Physical Oceanography",
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year = "1976",
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publisher = "American Meteorological Society",
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address = "Boston MA, USA",
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volume = "6",
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number = "3",
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doi = "10.1175/1520-0485(1976)006<0379:AMFTTG>2.0.CO;2",
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