[MITgcm-devel] ICE workshop - recap and homework!

[Martin Losch]

Hi Hong,

this is something I introduced. It really should be the default, because without this flag, you will not be able to get a consistent long wave radiation budget. See this thread:
<http://mitgcm.org/pipermail/mitgcm-devel/2011-December/005079.html>
especially:
<http://mitgcm.org/pipermail/mitgcm-devel/2011-December/005080.html>
I am not surprised that it leads to different ice thicknesses, because the flag changes the radiation budget. You might be able to recover somethings similar as before with setting the ice_emissivity=0.97 in data.exf. Now you use the default, which is 0.95


Martin



On Apr 2, 2012, at 11:00 PM, Hong Zhang wrote:

> Menemenlis, Dimitris (3248) wrote:
>> Martin, Gael, Ian, and Patrick, we also find that the new ice code (checkpoint63j) creates more ice than our previous integrations (also with non-legacy code but circa checkpoint63c).  We are trying to understand what is principal cause of this additional sea ice, so that we don't have to readjust everything from scratch.  Any advice on where to look would be appreciated.
>> 
>> Hong has summarized his results here:
>> http://ecco2.jpl.nasa.gov/data1/meeting/2012/03_28/hzhang_SO_seaice.ppt
>> http://ecco2.jpl.nasa.gov/data1/meeting/2012/03_28/SO_seaice.tar
>> Compare only JSO24 and JSO30 - ignore JSO29, which attempted to use SItracer instead of HSALT for salinity.
>> 
>> The differences between JSO24 and JSO30 are as follows:
>> 
>> JSO24:
>> SEAICE_OPTIONS.h
>> #define MCPHEE_OCEAN_ICE_HEAT_FLUX
>> #define GRADIENT_MIXED_LAYER_TURBULENCE_FACTOR
>> #define SEAICE_DO_OPEN_WATER_GROWTH
>> #define SEAICE_DO_OPEN_WATER_MELT
>> #define FENTY_AREA_EXPANSION_CONTRACTION
>> #define SEAICE_ADD_SUBLIMATION_TO_FWBUDGET
>> #define ALLOW_SEAICE_FLOODING
>> #define SEAICE_CAP_HEFF
>> 
>> JSO30:
>> EXF_OPTIONS.h
>> # define EXF_LWDOWN_WITH_EMISSIVITY
>> data.sea	ice
>>  SEAICE_no_slip     = .TRUE.,
>>  SEAICE_wetAlbTemp  = 0.0,
>>  SIsal0             = 4.0,
>>  SEAICE_mcPheePiston= 0.0008333,
>>  SEAICE_frazilFrac  = 0.1,
>>  SEAICE_mcPheeTaper=0.92,
>>  
> Hi all,
> We tried some more experiments to find the cause for the more seaice problem.
> By switching off EXF_LWDOWN_WITH_EMISSIVITY  (in EXF_OPTIONS.h )
> we can basically recover the result of old run,
> while other combination of run parameters make minor change.
> Will look into this flag of EXF_LWDOWN_WITH_EMISSIVITY.
> In the meanwhile, anybody has experience with EXF_LWDOWN_WITH_EMISSIVITY?
> thanks
> hong
> 
> 
> _______________________________________________
> MITgcm-devel mailing list
> MITgcm-devel at mitgcm.org
> http://mitgcm.org/mailman/listinfo/mitgcm-devel