noresmhub/cice

Development repository for the CICE sea-ice model

The CICE Consortium sea-ice model

CICE is a computationally efficient model for simulating the growth, melting, and movement of polar sea ice. Designed as one component of coupled atmosphere-ocean-land-ice global climate models, today’s CICE model is the outcome of more than two decades of community collaboration in building a sea ice model suitable for multiple uses including process studies, operational forecasting, and climate simulation.

This repository contains the files and code needed to run the CICE sea ice numerical model starting with version 6. CICE is maintained by the CICE Consortium. Versions prior to v6 are found in the CICE-svn-trunk repository.

CICE consists of a top level driver and dynamical core plus the Icepack column physics code], which is included in CICE as a Git submodule. Because Icepack is a submodule of CICE, Icepack and CICE development are handled independently with respect to the GitHub repositories even though development and testing may be done together.

The first point of contact with the CICE Consortium is the Consortium Community Forum. This forum is monitored by Consortium members and also opened to the whole community. Please do not use our issue tracker for general support questions.

If you expect to make any changes to the code, we recommend that you first fork both the CICE and Icepack repositories. In order to incorporate your developments into the Consortium code it is imperative you follow the guidance for Pull Requests and requisite testing. Head over to our Contributing guide to learn more about how you can help improve CICE.

Useful links

• CICE wiki: https://github.com/CICE-Consortium/CICE/wiki

  Information about the CICE model

• CICE Release Table: https://github.com/CICE-Consortium/CICE/wiki/CICE-Release-Table

  Numbered CICE releases since version 6 with associated documentation and DOIs.

• Consortium Community Forum: https://xenforo.cgd.ucar.edu/cesm/forums/cice-consortium.146/

  First point of contact for discussing model development including bugs, diagnostics, and future directions.

• Resource Index: https://github.com/CICE-Consortium/About-Us/wiki/Resource-Index

  List of resources for information about the Consortium and its repositories as well as model documentation, testing, and development.

License

See our License and Distribution Policy.

cice's Issues

CICE does not restart correctly in wave/ice coupling

The following field from CICE is not bfb on restart:

 iceImp_Si_floediam   (iceImp_nx,iceImp_ny,time)  t_index =      1     1
        311   138240  (   325,   359,     1) (     1,     1,     1) (    31,    66,     1) (    31,    66,     1)
              138240   1.674731125838850E+03   0.000000000000000E+00 4.3E+01  3.103339245842001E+01 1.5E-05  3.103339245842001E+01
              138240   1.674731125838850E+03   0.000000000000000E+00          7.371746970397571E+01          7.371746970397571E+01
              138240  (   325,   359,     1) (     1,     1,     1)
          avg abs field values:    3.306170191991240E+01    rms diff: 1.2E-01   avg rel diff(npos):  1.5E-05
                                   3.306208736543892E+01                        avg decimal digits(ndif):  6.9 worst:  0.2
 RMS iceImp_Si_floediam               1.1756E-01            NORMALIZED  3.5558E-03

The above was obtained as follows:

Create a case with the following command (modify for your own username and srcroot):

> ./create_newcase --case /cluster/home/mvertens/noresm/test_blom_ww3_debug2 --res T62_tn14_wtn14 --compset 2000_DATM%NYF_SLND_CICE_BLOM_DROF%NYF_SGLC_WW3DEV --project nn9560k --user-mods-dir /cluster/home/mvertens/src/noresm_develop_v6_base/cime_config/usermods_dir
s/wav_ice_coupling --run-unsupported --mach betzy

1. Run 1 - do a 30 step initial run - writing coupler and ww3 history files every time step and restart files only at the end of the first day

> ./xmlchange STOP_N=30
> ./xmlchange STOP_OPTION=nsteps
> ./xmlchange HIST_N=1
> ./xmlchange HIST_OPTION=nsteps
> ./xmlchange REST_N=1
> ./xmlchange REST_OPTION=ndays

Move the hi history files to a temporary directory

2. Run 2 - do a 6 time step restart run from the restart files produced in 1.
   > ./xmlchange CONTINUE_RUN=TRUE

Now compare the first history file after restart with the history file from the initial run. In my case this was:
cprnc test_blom_ww3_debug2.cpl.hi.0001-01-02-03600.nc debug_rest2/test_blom_ww3_debug2.cpl.hi.0001-01-02-03600.nc

Note that cprnc is in /cluster/shared/noresm/tools/cprnc/cprnc
You will load to do the following first
> module load netCDF/4.8.1-iompi-2021b

NOTE: You will need the code for the ww3 PR NorESMhub/WW3#8 in order to be able to duplicate these results.