[MITgcm-devel] non-legacy seaice

[Fenty, Ian G (3248-Affiliate)]

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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