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CICE version 4.1
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@duvivier duvivier released this 30 Jan 18:28
· 378 commits to main since this release
cice-4.1
138f087

Changes through revision r277

Added an alternative parameterization for ice conductivity suggested by Pringle et al. (JGR 2007) and tuned the gx1 configuration to improve the ice thickness simulation. These changes involved several parameters now in namelist, including the ice thickness above which bare ice albedo is constant, a flag for the conductivity parameterization, a parameter that determines the ridged ice thickness distribution, and the minimum friction velocity for oceanic heat flux to the underside of the ice. A manuscript submitted to Ocean Modelling entitled "Sea Ice Thickness Sensitivities" documents these changes (contact E. Hunke).

Implemented two tracers for tracking the ridged ice area and volume. The actual tracers are for level (undeformed) ice area and volume, which are much easier to implement. Ice that is not level is recognized as ridged. Both level ice and ridged ice are offered as history output.

Added a column configuration. Because of the boundary conditions and other spatial assumptions in the model, this is not a single column, but a small array of columns (minimum grid size is 5x5). However, only the single, central column is used (all other columns are designated as land).

The history module has been generalized to allow output at different frequencies. Five output frequencies ('1', 'h', 'd', 'm', 'y') are available simultaneously during a run. The same variable can be output at different frequencies (say daily and monthly) via its f_ string in namelist.
Variables with a third and/or fourth dimension (i.e., vertical; categories) are also available for output in the history files.

Reduced work and memory needed for multiple tracers. Originally the number of tracers was fixed, but in CICE version 4 some tracers may be turned off at runtime. Arrays and loops have been reduced to the size needed only for active tracers.

Added an alternative "T-fold" tripole grid option. The tripole option in CICE 4.0 is for "U-fold" grids.

Corrected bugs, particularly for nonstandard configurations (for example, nghost=2).

Except for the albedo diagnostic output, results are bit-for-bit identical to those from the previous release when using the same parameter set (conduct='MU71', ahmax=0.5, mu_rdg=4, ustar_min=0.05). Some of these parameters have changed in the new, default ice_in files (for gx1 and col configurations, not for gx3). In particular, ustar_min was much too large and has been reduced to 0.0005 m/s. Now, ahmax=0.3 m corresponds with the World Meteorological Organization's definition of white ice.

physics

  • Added tracers for tracking the ridged ice area and volume
  • Tuned the gx1 configuration to improve the ice thickness simulation (namelist parameters: conduct, ahmax, mu_rdg, ustar_min)
  • Added option for Pringle et al (2007) conductivity

infrastructure

  • Simplified and corrected some index calculations for neighbor blocks
  • Generalized indices for mapping data to ghost cells when nghost>1
  • Increment and count tracers during initialization instead of hardwiring them
  • Arrays and loops have been reduced to the size needed only for active tracers
  • Added new, alternative "T-fold" tripole grid option
  • Implemented an alternative method for averaging points along the tripole grid cut
  • Added column configuration
  • Moved several hardwired parameters into namelist

diagnostics

  • The history module has been generalized to allow output at different frequencies and for additional dimensions
  • Use 'ppt' to denote salinity units instead of 'psu'
  • Call ice_write_hist initially only if write_ic is true
  • Corrected albedo weights used in diagnostics
  • Corrected indices in diagnostic routine quasilocal_max_min

bug fixes

  • Match order of operations for derived grid quantities to prevent round-off differences along the tripole grid cut.
  • Use 0 instead of puny for conditional to load tracer array, for conservation
  • Limit call to atmospheric boundary layer calculation by icells
  • Correct calendar for 360-day years.
  • Correct field_loc and field_type in some subroutine calls
  • Declare subroutine argument ns outside of netcdf ifdef in routine icecdf
  • Remove ustar_scale
  • Remove continuation from declaration statement in ice_flux.F90
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