[MITgcm-support] on the control of sea ice growth

[Martin Losch]

Hi,

these parameters control the speed at which excess heat (for freezing) is turned into sea ice at the bottom of the sea ice (from SEAICE_PARAMS.h):

C     SEAICE_mcPheeTaper :: tapering down of turbulent flux term with ice
C                           concentration. The 100% cover turb. flux is
C                           multiplied by 1.-SEAICE_mcPheeTaper
C     SEAICE_frazilFrac  :: Fraction of surface level negative heat content
C                           anomalies (relative to the local freezing point)
C                           may contribute as frazil over one time step.

with SEAICE_frazilFrac = 1 (default), all heat is turned into ice within one time step (which is probably what you have). So try SEAICE_frazilFrac = SEAICE_deltaTtherm/(3 days), for example. (you can also specify the 3 days as SEAICE_gamma_t_frz, see seaice_readparm.F for details).

Martin



> On 15 Nov 2016, at 04:31, whale <250107302 at qq.com> wrote:
> 
> Dear friends
> 
> Recently, when I set up an experiment to simulate the Antarctic region, I suffered from a tricky question. As we known, when the sea surface layer become super-cooled (cooler than the in situ freezing point temperature) around the Antarctica continental shelf, the sea ice will grow. Then, the temperature of the surface layer will be warmed up to the freezing point by extracting the latent heat released from the growth of sea ice. Now, the question is that I have got a source of super-cooled water mass which comes from the ocean cavity beneath the ice shelf. When this super-cooled water mass ascend to the surface layer, huge latent flux are continuously extracted to warm this super-cooled ice shelf water up to the freezing point by the sea ice growth. As a result, the Qnet seems to be incredible large (up to ~1e4 W/m2/s) at where the ice shelf water outcrop the sea surface in the astral summertime.
> 
> I want to know is if there is a parameter in the namelist to control the sea ice growth when the surface layer is super-cooled, and thereby I can slow down this process to prevent the incredible large heat flux at where the ice shelf water outcrop. Any suggestions and comments are appreciated.
> 
> Cheers
> 
> 
> Chengyan Liu
> 
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