Force ktherm=1 to disable CICE mushy layers scheme in CESM 2.3 a17b

[mike_scchen@gmail_com]

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[mike_scchen@gmail_com]

Sorry the edit took too long and expired :p

We're attempting to run GIAF_JRA compset with CESM 2.3 alpha 17b, and use its pop / cice restart to mix with our own TaiESM model (from CESM 1.2.2, but with modifled atm component) run.
Turns out that the TaiESM can read pop restart from JRA, but failed on cice for the variable names and ice layer schemes change.
Also, CICE4 has 4 ice / 1 snow layers while CICE5 has 8 ice / 3 snow layers.
The variables in question are esnon and eicen (internal energy per category and layer of snow and ice), which was saved in JRA restart as qsno001~003 and qice001~008.
Although the layering scheme is different, I tried to merge them by adding them up with NCO (qice001 + 002, 003+004, etc.) and write them into respective eicen / esnon variables.
The TaiESM reads them but cannot initialize with error:

(shr_sys_abort) ERROR: ice: Vertical thermo error

Another try is to rerun JRA with older layering scheme (ktherm=1).
I tried a cold start of GIAF_JRA with modified user_nl_ice, but it failed with:

(abort_ice)ABORTED:
(abort_ice) called from ice_step_mod.F90
(abort_ice) line number 602
(abort_ice) error = (step_therm1)
ERROR: (abort_ice)(step_therm1)

(init_vertical_profile)Starting zSin < min_salin, layer 1
(init_vertical_profile)zSin = 2.619941406447798E-002
(init_vertical_profile)min_salin = 0.100000000000000
(icepack_warnings_setabort) T :file icepack_therm_vertical.F90 :line
872
(init_vertical_profile) init_vertical_profile: Starting zSin < min_salin, layer
(icepack_warnings_aborted) ... (thermo_vertical)
(icepack_warnings_aborted) ... (icepack_step_therm1)
(icepack_step_therm1) ice: Vertical thermo error, cat 3

Any suggestions? or this attempt is doomed from the start?

 

[mike_scchen@gmail_com]

Okay with help from colleagues, it seems that I need to multiply the qice* with vicen to produce eicen. testing...

 

[dbailey]

Moving this to the CESM_CICE forum. So, if I understand correctly you are trying to use a CICE4 style initial file for a CICE6 based run? This is very tricky and as you have found out this requires distributing the 4 layers over 8 layers and converting energy to enthalpy.

I actually have an FAQ on this.

FAQ: CICE4 to CICE5 initial files

In order to use CICE4 initial files with the new CICE5 code base in CESM2 requires some processing in order to avoid problems. Note that CICE5 is the only code base available in CESM2, so if you want to use older CICE4 files to initialize a run they will need to be converted. We have an NCL tool...

bb.cgd.ucar.edu

Now, if you are simply trying to run CESM2.3 with ktherm=1, I would recommend resetting ice_ic to 'default'. You can add the following to user_nl_cice;

ice_ic = 'default'
ktherm = 1
nslyr = 1
nilyr = 4

I just did a run with this myself. :)