[MITgcm-devel] non-legacy seaice

[Martin Losch]

Hi Jean-Michel and others,

thanks for your comments. I did not plan on using the non-legacy code "by default", I just thought that it is interesting that just turning it one is far from safe.

I'll try with Ian's options. Why isn't this combination the default in pkg/seaice/SEAICE_OPTIONS.h?

M.

On Jan 31, 2012, at 6:56 AM, Jean-Michel Campin wrote:

> Hi Martin,
> 
> Just a short comment: if Gael does not want to answer, you can
> always return to SEAICE_GROWTH_LEGACY version, or, as an other
> alternative, switch to pkg/thsice thermodynamics as Jeff did.
> 
> Cheers,
> Jean-Michel
> 
> On Mon, Jan 30, 2012 at 12:52:13PM -0500, Jean-Michel Campin wrote:
>> Hi Martin,
>> 
>> I heard form 2 other users (Jeff Scott and Gael, but both with
>> similar options & params) a similar issue regarding unrealistic 
>> surface temp.
>> So, I think it's a more general problem that just our set-up.
>> 
>> Cheers,
>> Jean-Michel
>> 
>> On Mon, Jan 30, 2012 at 05:04:48PM +0100, 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
>>> 
>>> 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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