[MITgcm-devel] non-legacy seaice

[Martin Losch]

Hi Ian,

I tried with your option combination, and the problem does not go away (THETA=-37degC). What do you suggest?

Martin

On Jan 30, 2012, at 6:27 PM, Fenty, Ian G (3248-Affiliate) wrote:

> 
> On Jan 30, 2012, at 8:04 AM, Martin Losch wrote:
> 
>> Dear sea-ice modelers,
>> 
>> just out of curiosity I turned on the non-legacy seaice code (SEAICE_GROWTH_LEGACY undefine and SEAICE_SOLVE4TEMP_LEGACY undefined and set some other flags that go along with it, see below). To further my boldness, I also turned on:
>> #define MCPHEE_OCEAN_ICE_HEAT_FLUX
>> #define GRADIENT_MIXED_LAYER_TURBULENCE_FACTOR
> 
> Martin,
> The non-legacy compile time sea ice flags are not independent.  The set of flags for which I have confidence is:
> 
> #undef SEAICE_GROWTH_LEGACY
> #undef SEAICE_SOLVE4TEMP_LEGACY
> 
> #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
> 
> As for the recent SEAICE_HEAT_CONSERV_FIX, I can say nothing because there was no documentation about it in devel (as far as I noticed) and minimal documentation in the code.  Perhaps it is unnecessary when not coupling with an active atmosphere?    
> 
> Anyhow, with that above set of flags I can help diagnose any problems (e.g., with unexpectedly cold surface temperatures) and nonzero HEFF over land.  Please rerun the simulation if you can!
> 
> -Ian
> 
> 
>> The solutions that I get for an Arctic domain are comparable but different. The non-legacy code gives generally thicker ice in the interior, which I think is generally good, as the legacy code tends to produce ice that's on the "thin side" compared to other solutions.
>> 
>> However (appart from the fact that there was HEFF~=0 over land), I get very cold surface temperatures (down to -21degC) in some areas (Lena Delta), interesting this starts in June/July when ice should be melting. That's clearly not very physical and I am wondering if others have observed this behavior. Is there a solution to this? Before I try it myself, is it connected to the 
>> #define MCPHEE_OCEAN_ICE_HEAT_FLUX
>> #define GRADIENT_MIXED_LAYER_TURBULENCE_FACTOR
>> flags? (Likely, isn't it?) Or  SEAICE_OCN_MELT_ACT_ON_AREA?
>> 
>> Your experience with this is appreciated ...
>> 
>> Martin
>> 
>> PS. Here are the relevant flags:
>> C--   make conservation of freshwater complete
>> #undef SEAICE_ADD_SUBLIMATION_TO_FWBUDGET
>> 
>> C--   Use the Old version of seaice_growth (close to cvs version 1.70)
>> C     otherwise, use the merged version (with some of Ian Fenty s code)
>> #undef SEAICE_GROWTH_LEGACY
>> 
>> C--   options only available in the merged version (from Ian Fenty s code)
>> #ifndef SEAICE_GROWTH_LEGACY
>> C-    to ensure heat conservation in the coupled ocean-seaice system
>> #define SEAICE_HEAT_CONSERV_FIX
>> C-    to switch on/off open-water freezing contribution to thickness tendency:
>> # define SEAICE_DO_OPEN_WATER_GROWTH
>> C-    ifdef SEAICE_DO_OPEN_WATER_GROWTH then define SEAICE_DO_OPEN_WATER_MELT
>> C     to also allow open-water air-sea heat fluxes melt ice
>> # undef SEAICE_DO_OPEN_WATER_MELT
>> C-    to switch on/off ocean heat contribution to seaice cover reduction:
>> # define SEAICE_OCN_MELT_ACT_ON_AREA
>> C-    to preclude infinitesimal ice concentrations:
>> # undef ALLOW_PRECLUDE_INFINITESIMAL_AREA
>> #endif
>> 
>> C-    to use the MCPhee formula in computing ocean/ice fluxes
>> #define MCPHEE_OCEAN_ICE_HEAT_FLUX
>> #define GRADIENT_MIXED_LAYER_TURBULENCE_FACTOR
>> 
>> C--   Use the Old version of seaice_solve4temp (formerly seaice_budget_ice)
>> C     otherwise, use Ian Fenty s version
>> #undef SEAICE_SOLVE4TEMP_LEGACY
>> 
>> 
>> 
>> 
>> 
>> 
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> 
> 
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