Skip to content

CICE - Sea Ice

CICE5

In ACCESS-ESM1.6, the sea ice component is CICE5 (Hunke et al., 2015)1 updated from CICE4 used in ACCESS-ESM1.5.

Scientifically the sea ice model is configured the same as ESM1.5 (Ziehn et al., 2020)2. The scientific configuration is summarised as follows:

  • Zero-layer thermodynamics (Semtner, 1976)3
    • One layer of snow and one layer of ice
    • UM calculates ice surface temperature, and conductive heat flux into the sea-ice
  • Ice transport (Lipscomb, 2001)4 and ridging (Rothrock, 1975)5
  • Internal Ice Stress follow EVP (Hunke & Dukowicz, 2002)6

There are significant improvements to diagnostics to support CMIP style diagnostics (Notz et al., 2016)7(Fox-Kemper et al., 2025)8 natively and error handling.

Meltwater Runoff

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. As there is no ice sheet model, the volume of meltwater discharge from Antarctica and Greenland is equal to the instantaneous precipitation over each continent. In ESM1.6, this 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 with a prescribed pattern from the lice_discharge_iceberg.nc input file.

References

  1. Hunke, E., Lipscomb, W., Turner, A., Jeffery, N., & Elliott, S. (2015). CICE: The los alamos sea ice model documentation and software user's manual, version 5.1. doc. LA-CC-06-012. ↩

  2. Ziehn, T., Chamberlain, M. A., Law, R. M., Lenton, A., Bodman, R. W., Dix, M., Stevens, L., Wang, Y.-P., & Srbinovsky, J. (2020). The Australian Earth System Model: ACCESS-ESM1.5. Journal of Southern Hemisphere Earth Systems Science, 70(1), 193--214. https://doi.org/10.1071/ES19035 ↩

  3. Semtner, A. J. (1976). A model for the thermodynamic growth of sea ice in numerical investigations of climate. Journal of Physical Oceanography, 6(3), 379--389. https://doi.org/10.1175/1520-0485(1976)006\<0379:AMFTTG>2.0.CO;2 ↩

  4. Lipscomb, W. H. (2001). Remapping the thickness distribution in sea ice models. Journal of Geophysical Research: Oceans, 106(C7), 13989--14000. https://doi.org/https://doi.org/10.1029/2000JC000518 ↩

  5. Rothrock, D. A. (1975). The steady drift of an incompressible arctic ice cover. Journal of Geophysical Research (1896-1977), 80(3), 387--397. https://doi.org/https://doi.org/10.1029/JC080i003p00387 ↩

  6. Hunke, E., & Dukowicz, J. K. (2002). The elastic--viscous--plastic sea ice dynamics model in general orthogonal curvilinear coordinates on a sphere---incorporation of metric terms. Monthly Weather Review, 130(7), 1848--1865. https://doi.org/10.1175/1520-0493(2002)130\<1848:TEVPSI>2.0.CO;2 ↩

  7. Notz, D., Jahn, A., Holland, M., Hunke, E., Massonnet, F., Stroeve, J., Tremblay, B., & Vancoppenolle, M. (2016). The CMIP6 Sea-Ice Model Intercomparison Project (SIMIP): Understanding sea ice through climate-model simulations. Geoscientific Model Development, 9(9), 3427--3446. https://doi.org/10.5194/gmd-9-3427-2016 ↩

  8. Fox-Kemper, B., DeRepentigny, P., Treguier, A. M., Stepanek, C., O'Rourke, E., Mackallah, C., Meucci, A., Aksenov, Y., Durack, P. J., Feldl, N., Hernaman, V., Heuzé, C., Iovino, D., Madan, G., Marquez, A. L., Massonnet, F., Mecking, J., Samanta, D., Taylor, P. C., ... Vancoppenolle, M. (2025). CMIP7 data request: Ocean and sea ice priorities and opportunities. EGUsphere, 2025, 1--58. https://doi.org/10.5194/egusphere-2025-3083 ↩